We live in an age where the cosmetics industry is evolving at lightening speed. Almost no longer is a person using only face cream. Most of us use at least 3 products or more at a time. This is called cosmetic layering. The layering method has many advocates, but more and more opponents are also found.

Layering is a skin care technique that comes from Asia. This technique consists of applying various cosmetic products to the face in a certain order. We often think that this technique is popular only among Asians. Layering is a technique that is used by more and more people who dedicate more to their skin than just face cream.

How bad is layering cosmetic products really?

So, the opponents of layering accuse this method of applying amount of preservatives that exceeds the maximum concentration on the skin. Manufacturers rarely use the maximum amount of preservatives allowed. Maximum allowable concentrations are set so that even the most sensitive skin does not develop a reaction. Another thing to know here is that concentrations do NOT add up! Just as SPF does not add up, so do concentrations.

If you have 100 ml of tonic containing 0.1% phenoxyethanol and 250 ml serum containing 0.15% phenoxyethanol this is not 0.35% phenoxyethanol. Unfortunately, the calculation is not so easy. While you need to know that you cannot calculate the concentration of two different preservatives. The calculation is only possible for the same ingredient.

The calculation shows that the total concentration is 0.13%, which means that the concentration increase is minimal. Such deviations would only cause problems for people with really sensitive skin. So if you want, you still use face tonic as these preservatives will not “eat away” your face because of one coat anymore.

About the layering of several different preservatives, have you ever wondered that even in many cosmetics, many different preservatives are used to maximize product protection? If there is no scare on that product, then we don’t need to scold it here either.

How to layer Cosmetic Products Properly?

In the case of layering, there is one simple rule: always apply the least viscous product first. Then we continue with more viscous products. The skin care process is always started with water-based products, ie tonic, moisturizing serum, serum with active ingredients based on water. Water-based products make it easier to cross the skin and therefore need to be applied first.

Why would water-based products cross your skin?

We should think of the skin as a structure containing large molecules such as squalene, fatty acids, waxes, esters and triglycerides. These molecules are huge compared to water, but they are not clustered together like bricks, but there is some space between them. Because of this space between the larger molecules, water can flow from the skin (transepidermal water loss) and into the skin!

The most viscous products such as creams, oils or butter should be applied at the end. For the most part, these ingredients act emolliently and occlusively. Occlusive action means that these products form a water-tight film on the surface of the skin. So it is a good idea to apply a water-based serum before the cream or oil, as moisture will lock into the skin. Namely, the problems with applying oil first and then water-based serum are more problematic.

• The active ingredient in the serum would not reach the skin – water and oil were repelled, so the water-based serum would remain on the surface of the oil

• A drop of serum that would be on the surface of the oil would evaporate over time

So it’s a shame to throw serum away. However, we should be aware that no product forms an occlusive layer on the skin for a very long time. Also, occlusive creams that are designed to prevent moisture loss and other substances from penetrating the skin are not exactly flowering in the performance of their function.

Particular attention should be paid to the active ingredients

Some cosmetically active ingredients are very effective, but they are known to have poor skin penetration. An example of such an active ingredient is vitamin C (ascorbic acid), which crosses the skin barrier very poorly. Therefore, such ingredients should be used in the first stages of care so that they are as close as possible to the skin and thus have a greater chance of reaching the desired site.

What is the correct order of product layering?

We first start with a tonic to restore the skin’s natural pH. We continue with a water-based serum designed to moisturize the skin (hyaluronic acid, glycerol, ..) or a serum containing active ingredients (acids, vitamin C, vitamin B, peptides). The last step, as mentioned above, is to apply a cream or oil that locks all previously applied ingredients into the skin. During the day, make sure to apply sun cream!

Excessive use of the active ingredients can irritate the skin!

There is nothing wrong with layering cosmetics. As long as you layer products that mostly provide moisture, there are few things that could go wrong. However, the same does not apply to active ingredients. Using too many active ingredients increases the potential for them to “fight” with each other. This can cause skin irritation or incomplete passage into the skin. Incomplete passage causes the ingredient to remain on the skin, which can clog pores and subsequently cause pimples.

Because ingredients are more active and effective than ever before, they can also irritate the skin if you overdo them or use them in combinations that are not suitable for your skin type. One of the common mistakes with which we overload the skin is to combine products containing glycolic or salicylic acid with retinoids at the same time – so that we use both in the evening.

The stronger the product, the more conservative we are about the amount of application and the frequency of use.

What is your opinion on the layering of cosmetics?

We regularly protect our body with sunscreen, as today’s society is becoming more aware of the harmful effects of UV radiation. The only area on the body that we do not protect is hair. However, UV radiation can also affect the properties and appearance of hair. What happens to hair when the unprotected are exposed to the sun and what products can protect them?

Like other tissues, hair is made up mostly of proteins. Hair consists of 85% keratin, 1-3% lipids, trace metal ions (aluminum, chromium, calcium, magnesium), water and pigments. UV rays have a high protein breakdown ability, so it’s no surprise that summer can be a difficult period for the hair.

UV hair protection is important

Many people are unaware that their hair is also affected by UV radiation. In the scientific literature, hair damage from UV radiation is associated with dryness, increased breakage and split tips, lower shine, and increased roughness of the hair surface. Not all of these changes occur immediately or all in the same place.

UVB radiation affects the hair approximately 5 μm below the surface. For healthy hair, it is primarily the outer layer. In the case of hair that has already been severely damaged by intensive bleaching and heat treatments, the outer layer may be absent. In this case, UVB radiation is exposed to the cortex of the hair. UVA radiation is less intense, but it can penetrate deeper and may affect the entire cortex.

All The Ordinary and NIOD products can be purchased at Beautyology.eu.

To some extent, hair can protect itself

Melanin is a pigment that is responsible for skin and hair color and protection against the harmful effects of sunlight. An interesting fact is that blacks are rarely burned by the sun, as their melanin is significantly more active than ours and therefore protects them from burns. The same goes for hair. Eumelanin, which is present in individuals with darker shades of hair, is more photostable than pheomelanin, which is predominant in redheads and those with lighter hair. Therefore, darker hair is more protected than lighter hair.

Melanin works by disabling the free radicals that form when exposed to UV radiation. This prevents free radicals from affecting keratin, the main protein in the hair. In the process, damage to the melanin molecule occurs, which turns light. This is the reason we have lighter hair at sea than we usually do.

Why does hair get grey and why isn’t it protected?

Hair turns gray when pigmentation stops. Pigments are secreted by stem cells that begin to die off. The stem cells in the upper layer of the skin develop into melanin-producing cells. Melanin-producing cells are called melanocytes. Melanocytes transfer the pigment to growing hair, making the hair a distinctive color. As we age, the stem cells start to die off and no longer develop into melanocytes, so the hair becomes gray.

When the hair ages, there are no more melanin-forming cells. So when melanin is gone, we no longer have a molecule to protect our hair from the harmful effects of UV radiation. Exposure to the sun can do more damage to such hair, as they are less resilient. A group of people with such hair needs the highest UV protection.

In what ways can the sun affect the properties of your hair?

  • Formation of free radical substances (ROS)
  • Discoloration
  • Disruption of disulfide bridges
  • Changes to the cuticle
  • Some amino acids absorb UV light and form free radicals that break the disulfide bonds.
  • In darker hair, melanin can be photooxidized, while in lighter hair, some amino acids are destroyed, causing discoloration.
  • Keratins in the hair are interconnected by disulfide bonds – bridges. Light breaks them down to form cysteic acid, which in turn makes hair less resilient and less elastic.
  • Melanin is found in the inner layer of the hair, but not in the outer layer, so it is not protected. After that, it is most exposed to UV radiation. The “roofers” that make up the cuticle are more open and lose weight.

Are UV protection products the hair solution?

For the protection of hair we use various products to which manufacturers add UVA and UVB filters as classic sunscreens that we use to protect the skin. The main problem with these products is that they cannot be applied evenly over the entire surface of the hair, which means that some parts of the hair are not protected. Another challenge is to create a sun protection formulation that will adhere to the hair shaft. In addition, it is almost impossible to apply a uniform thickness of sunscreen to all your hair without looking greasy.

How do UV hair protection products work?

Some shampoos for colored hair contain UV filters, as this should prolong the color lifespan (prevent fading). However, the problem again arises with shampoos as these products need to be completely rinsed off the surface of the hair and thus some UV filters can also be flushed. As a result, the ability to protect hair is limited.

A better approach to UV hair protection is to use balms that form a film on the surface of the hair that is not rinsed between 15-30 minutes. As a result, UV filters can adhere better to hair and offer more effective protection.

Hair styling products are probably the most effective in providing photoprotection. These products include non-rinse balms, gels and hair sprays.

If you massage balms that do not need to be rinsed, they will act as a heat protection agent and UV protection just before drying, as they remain on the hair.

The most effective products that protect against UV radiation are hair dyes

Non-pigmented hair (white, gray) is more prone to UV damage than pigmented hair. This means that molecules of hair dye trapped inside the hair provide some protection against UV damage. Although hair dyes damage the hair tissue, this way the hair is protected from the harmful effects of UV radiation. Hair coloring causes damage to the hair fibers, but when the hair is exposed to prolonged periods of UV radiation, the antioxidant effect of the dye that binds inside the hair outweighs the initial detrimental effect of dyeing. Hair dyes act as antioxidants that prevent the disulfide bonds in keratin from breaking.

What do UV hair protection products contain?

First of all, it should be emphasized that the regulations in the field of hair protection are not as strict as in the field of skin protection. We cannot determine the exact SPF protection factor for hair products. However, there is a Hair Protection Factor (HPF) based on the change in mechanical properties between protected and unprotected hair. There is also a Radical Hair Protection Factor (RHF) that differentiates products based on their ability to prevent ROS from UV radiation.

The products contain UV filters, silicones that form a hair film and antioxidants. In addition, hair protection products also contain moisturizers, emollients, antistatic agents as well as thermal hair protection substances. Natural extracts that protect the hair include walnut, beech, aloe vera, green tea, chamomile, lotus and oils such as monoi.

All The Ordinary products have been donated to create this post by Beautyology.eu.

Since the use of sunscreens has been on the rise, they have gained many advocates as well as many opponents. Opponents of sunscreens claim that they block the synthesis of vitamin D, which is essential for our health. There are also extreme opponents who claim that using sunscreens is more harmful than unprotected sun exposure. However, is it true that sunscreens block vitamin D synthesis?

Basic information on vitamin D

Vitamin D acts as a hormone in the body and is synthetized by UV light. Vitamin D comes in two forms (D₂, D₃). Vitamin D₂ is obtained from plant nutrition and oral supplements. Vitamin D₃ is mainly obtained by exposing the skin to ultraviolet B (UVB) radiation in sunlight and consuming foods such as oily fish. Vitamin D₂ and D₃ are metabolised in the liver and kidney to 1,25-dihydroxyvitamin D or calcitriol, which is a biologically active form. Calcitriol plays an important role in regulating the metabolism of calcium, phosphate for maintaining metabolic functions and for skeletal health.

How can one get vitamin D?

Vitamin D is also found in mushrooms, wheat germ oil, egg yolk, liver and fish oil. Vitamin D content in most foods ranges from 50 to 200 units per serving. Therefore, food cannot provide enough vitamin D, which is why most people synthetize it after sun exposure. Sun-induced vitamin D synthesis is strongly influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, use of sunscreens, passage through glass and plastic, and age.

Interesting fact: Even when older people are regularly exposed to sunlight, they produce 75% less vitamin D3 than young people.

Inadequate vitamin D intake can lead to postmenopausal osteoporosis and reduced bone density. Low vitamin D intake is also associated with heart and vascular diseases, depression, dementia and other conditions.

How is vitamin D synthesized after sun exposure?

Vitamin D3 can be produced in the skin when exposed to ultraviolet radiation B (UVB), so it is possible to increase vitamin D3 levels by exposure to UVB rays. During exposure to sunlight, radiation with a wavelength of 290–315 nm penetrates the skin. Most of this UVB radiation is absorbed in the epidermis, so when exposed to sunlight, most of the vitamin D3 is produced in the skin, in the living cells of the epidermis.

A quick recap on UV radiation

As we already know, exposure to UV radiation is not safe. Namely, we divide the UV spectrum into ozone-retained UVC rays, UVB rays that cause sunburns, UVA rays that cause photoaging. Unnecessarily prolonged exposure to UV light without protection can lead to skin cancer. For a reason, sunscreens have been developed to protect us from the harmful effects of UV radiation. Sun creams are designed to absorb and partially repel UVB radiation.

All The Ordinary and NIOD products can be purchased at Beautyology.eu, where you can use code COSMEDOC10.

If sunscreen blocks UVB rays does it block vitamin D synthesis as well?

Well, here we are. Where scientists from different disciplines are arguing with each other. Last time, I heard from a colleague that one dermatologist claimed that reduced vitamin D synthesis from sunscreens is more harmful than unprotected sun exposure. To put it mildly, I was almost hit by a stroke, but let’s go down the line. Sunscreen with sun protection factor (SPF) 30 absorbs approximately 96% of UVB radiation. So, by adding 2 + 2, topical application of sunscreen with SPF 30 reduces the skin’s ability to produce vitamin D3 by the same amount, ie 96%.

In principle, we calculated that only 4% of UVB radiation can access our skin with SPF 30, which is a very low chance for vitamin D synthesis, right? But this is where  you need to ask yourself how much sunscreen you really apply to your skin. In order to achieve the protection stated on the packaging – so in our case SPF 30 we need to apply 2mg / cm2 of skin. For the whole face, this means two full fingers of the cream.

A short calculation to back up my claims

The average surface area of ​​all skin in an adult is 1.5-2.0 m². So if we need to apply 2mg / cm² the calculation is as follows.

The result is 32 g per coat. Therefore, 1/3 of the entire 100 ml tube of sunscreen should be used to properly protect the entire body. Of course, we did not take into account that the sunscreen should be reapplied every 2 hours.

Let’s be real, we apply such a small amount of sunscreen to the body that the question is if we have an SPF protection factor of 5. So with SPF 5, we are about 70% protected against UVB radiation. This may sound like a lot, but this time it can pass as much as 30% of UVB radiation to the skin! Not to mention some body parts that are not usually protected at all. Or maybe we are in the shade and don’t put sunscreen on because the UVB rays can’t reach us. All of these unprotected parts allow 100% passage of UVB radiation and thus synthesis of Vitamin D, but also increased chances of skin cancer.

UVA protection is beneficial for Vitamin D

A number of studies investigating the influence of sunscreen on vitamin D synthesis have found that the use of sunscreen is likely to have minimal impact on vitamin D. UVA rays have no effect on vitamin D synthesis, although one in vitro study showed that UVA2 (315–340 nm) can cause vitamin D to break down, in which case protection against UVA may be beneficial for vitamin D production.

Controlled field studies with true sun exposure are the best way to determine the effect of sunscreen on vitamin D synthesis. The results of such studies report that no change in serum 25 (OH) D3 vitamin concentration occurs despite the use of sunscreen.

In fact, most studies published to date have shown no association between the use of sunscreens and vitamin D deficiency, nor with regular use of SPF> 15. In general, other protective methods (eg, shading, wearing protective clothing and long sleeves) ) affect vitamin D status more than using sunscreens.

UV radiation is more dangerous than sunscreens

Daily skin protection is recommended for all skin phototypes. This includes staying in the shade, wearing headgear and clothing, wearing sunglasses, and applying broad-spectrum sunscreen. These strategies will help prevent sunburn and skin cancer. The use of sunscreen for daily sun protection does not compromise the synthesis of skin vitamin D synthesis, even when the sunscreen is used in the predicted amounts (2mg / cm2). Increasing UVA-PF in sunscreens, however, even improves vitamin D3 production.

In case of reduced vitamin D level, this should be replaced. Oral supplementation is easy and does not pose significant risks. The risk-benefit calculation shows that, instead of sunbathing, it is better to take nutritional supplements with this vitamin to increase vitamin D3 levels.

The only light spectrum we talk about is UV light spectrum. However, the light spectrum also contains visible light and IR radiation. What are the effects of visible light on the skin and should we be protected from visible light as well?

Firstly, let’s get it clear. What is visible light?

Visible or blue light is an electromagnetic wavelength between 400 and 700 nm. This spectrum is able to be seen by a naked eye, well to most of the population. Some people aren’t able to see the full spectrum and somebody can see beyond the spectrum.

When a beam of visible light reaches to a body, the photons can be reflected or absorbed on the surface of this body. They can penetrate the body or be absorbed or dispersed into components. The last option for photons is to continue their path undisturbed.

Why is the sky more blue on days with no clouds and at sunset yellow or red?

The sky is blue because the blue photons are better scattered by the air molecules and are directed to our eyes. At sunset, we can see the sky red, because blue photons are scattered away so we can’t see them and on the , there are only red or yellow photons, which can be detected by a naked eye. At sunset, the journey of the light through the atmosphere to our eyes is longer than it is at midday.

Why do we see blood red?

Blood is red because it absorbs blue and green wavelength and red is being reflected. The grass is green because it absorbs red and blue wavelengths and the green is being reflected.

Energy dynamics

Why are we explaining all this? Molecules are able to form new chemical structures with other molecules being particular states. They can also transfer an electron to other molecules to create reactive oxygen species (ROS), which are able to destroy our DNA. Studies have shown that visible light doesn’t only affect the ROS but also matrix metalloproteases.

Visible light and skin

Melanin is responsible for skin color and can be found in the epidermis. Melanin partially absorbs visible light, which can cause hyperpigmentation and uneven skin tone. The dermis contains blood vessels that are capable of absorbing blue and green light. Other photons, which are scattered around can penetrate into adipocytes in subcutis. Fat cells are capable of partial absorption of red photons.

A candlelight dinner is therefore good for people with mature skin. The blood vessels in mature skin are closer to the surface and can absorb more blue and green light and the wrinkles are more visible on daylight. When we are next to candles this doesn’t happen, because candles absorb only red and yellow photons, which aren’t absorbed by blood and vessels are less visible (consequently are also wrinkles less visible).

Per unit of energy, visible light is 20 to 30 times less effect than UV, but there is 10 to 15 times more visible light in the solar spectrum than UV, so visible light cannot be neglected.

Good and bad qualities of visible light

Visible light helps to promote photoageing. It’s able to promote inflammation and consequently, inflammation phenomenon accelerates ageing. All that affects our DNA.

Those were bad news, but there are also good ones.

The use of foundation (powders) and other decorative cosmetics prevents visible light from harming us. Decorative cosmetics in fact protect us from the negative effects of visible light. Moreover, visible light even shows therapeutic effects (treatment of psoriasis, eczema, acne).

Acne

Porphyrins in Cutibacterium acnes (before Propionibacterium acnes) are particularly sensitive to visible light. When the skin is exposed to visible light, endogenous toxins are formed. They kill the microorganisms which are responsible for acne formation. Visible light alleviates inflammation, redness and aesthetic discomfort.

Bilirubin

Another positive effect is seen in premature babies. Their system isn’t capable of removing bilirubin. The accumulation of bilirubin increases the risk of jaundice which can harm brains and liver. Premature babies are irradiated with visible light because it’s able to reduce bilirubin to normal levels.

So how safe is the visible light?

If the blue light is used only for a short time, it doesn’t show negative effects and should be safe (skin testing in vivo). However, we don’t know what it would be like to be exposed to the visible light for a long time.

What seems curious is that while studying visible light, the radiation in the spectrum between 410 and 420 nm showed cytotoxicity to human fibroblasts. But wavelengths between 453 and 480 nm didn’t. This is pretty logical since the first two wavelengths are closer to UV radiation and exhibit similar effects as UV light, while the other two are longer wavelengths and they don’t show these effects. Therefore, it is believed that sunscreens should have UV protection above 400 nm as well.

Where can a blue light be found?

The most common source of blue light is electronic devices such as screens, tablets, smartphones, and LEDs. Studies suggest that blue light is also expected to have negative effects on our eyes.

What substances can protect us from the negative effects?

So far, has shown activity in the visible spectrum only: titanium dioxide, zinc oxide, bis-benzotriazolyl tetramethylbutylphenol (MBBT), but their protection is low. They tested 3 % titanium dioxide and 4 % MBBT, which were expected to block 50 % of blue light between 400 and 500 nm.

The microalgae extract Scenedesmus rubescens reduces the negative effects of blue light, also vitamins B3 and B6 have been tested on preventing blue light negative effects (table in “Into the blue”). Vitamin E also provides good protection against visible light.

Tested ingredients (vitamin B3, B6 and algae extract) inhibit the formation of ROS caused by blue light (source: Mendrok-Edinger C., Campiche R., Gadsinski K., Schuetz R. Into The Blue. Cosmetics and Toiletries 2018)

Also, carotenoids, which act as antioxidants, are able to protect the skin from the negative effects of blue light. In addition, their maximum activity is precisely in the visible light spectrum, so they may represent potential biological protection against blue light.

Mosquitoes are one of theworst ”pains in the neck” in the summer. The most disturbing noise is surely their “bzzzz” at night. In this blog, we’ll explain why the mosquito bites, why the bites itch and what we should use to get rid of the annoying and itchy mosquito bites.

Firstly something about mosquitoes!

There are nearly 3,500 different types of mosquitoes. When we say that we have been bitten by a mosquito, in most cases it’s by a female. Females are usually the ones that suck the blood of mammals. Women are drama queens, again :). Males are mostly fed with nectar only. The mosquitoes feed themselves from early dusk until the sunset.

Mosquitoes can be carriers of various diseases, most known to everyone is certainly malaria. The mosquitoes also carry dengue fever and yellow fever. Mosquitoes manage to transmit a disease to more than 700 million inhabitants per year. Only malaria kills 3 million people a year. It is true that tropical and subtropical areas are more exposed and the possibility of disease is greater, but this does not mean that Europeans are immune.

Tiger mosquitoes

They are a new species in Europe that originally came from Southeast Asia. It was first detected in Europe in 2006. It is mostly found near water and is really problematic.

Why are mosquito bites itchy?

We don’t notice the mosquito bite immediately, but only after a few minutes/hours. So, it’s not the mosquito bite that itches, but the immune reaction that follows the bite. Before the mosquito gets to the blood, it releases its saliva into the body. Substances in saliva prevent blood clotting during the sucking (anticoagulants), making their work much easier. Saliva also contains substances that are very immunogenic. Our body responds to these substances by making antibodies.

There are various types of immune responses. The reaction is carried out in a way that nothing happens at the first contact with the matter (first mosquito bite). At the first bite, the body is sensitized and memory cells are formed. But when have we ever gotten away with a single bite? When a mosquito bites us the next time, our body has already prepared memorial cells that then migrate to the point of the sting. At each subsequent sting, the immune response is faster.

Myth: ”Mosquitoes bite me because I have sweet blood”

The mosquitoes are said to more often sting younger people with hot skin and a strong body smell (not necessarily odor). They’ll love you even more due to the increased CO2 concentrations or in case you are wearing dark clothes or glitters.

How do get rid of mosquitoes with synthetic repellents?

DEET

N, N-diethyl-m-toluamide is a commercial ingredient used in repellents and it’s very effective. It is used for repellent activity against mosquitoes, ticks, fleas and other insects. According to studies, it irritates the skin.

How does it work?

There are 3 hypothesis, but in every case, it masks the scent and, consequently, the insects do not detect a person. DEET can only mask the smell that mosquitoes does not recognize or it changes to confuse the mosquito, and consequently, the mosquito does not recognize us as a host and will not sting.

Some repellents up for sale also contain up to 45 % DEET, which is an enormous amount and that can irritate the skin a lot.

A well-known synthetic repellent is also icardin, which also works against many types of insects. They are said to be less aggressive. Icardin is used in repellents up to 20 %.

Natural ingredients with repellent activity

Since the synthetic ingredients in repellents are unfriendly both for the ecosystem and for us, they have been looking for alternatives for repellent action in nature.

Essential oils of the camphor tree

The essential oil of camphor tree has proven to have a repellent effect. It also acts insecticidal, antifungal, antibacterial and as an antioxidant. Terpenoids and phenylpropanoids, found in leaves and bark, additionally contribute to the bioactivity of the camphor tree.

Curcumin

Is considered to be a cheap, non-toxic and easily accessible substance. You probably are much more familiar with the use of it in the kitchen. It is also a yellow dye that acts repellently and is used in cosmetics. It has positive effects on certain diseases, abnormalities, and syndromes.

Lemon eucalyptus

It produces citriodiol, which is an active ingredient in repellents. It irritates the skin minimally and works for 2-3 hours (maximum 6 hours). In repellents, it appears in concentrations up to 55 %.

Lavender

In a study, they tested 5 %, 10 % and 20 % concentration of essential oil. Essential lavender oil at a concentration of 5 % was sufficient for 40 minutes of protection against insects. While higher concentrations of essential oil were sufficient for 120 minutes of protection.

Peppermint

As a mosquito repellent a 1.5 % peppermint oil can be used, even in topical repellents. Peppermint essential oil also works against other insects. It works antifungal and antibacterial.

Other oils to repel insects within a natural way

Among them are citronella, eucalyptus, cinnamon, cloves, geranium, lavender, lemon, lemongrass, bergamot, red thyme, marjoram, spearmint and creeping (breckland) thyme.

Clove oil, creeping thyme oil and red thyme oil are the most effective repellents if used in the form of 3% essential oil. Polish thyme oil combined with citronella oil is an effective repellent combination that protects against insect bites up to 91 %.

Synergistic action

Oxford University tested basil and lantana extracts as repellents and found that they exhibit synergistic activity. In combination, they are longer effective against peak mosquitoes than individually. At the same time, the use of both together allows us to use lower concentrations of the extracts. They protect us from bites up to 120 or 150 minutes.

Safety warning for using synthetic repellents

In the study they used 20 % concentration of active ingredients, such as DEET and essential oils, in order to detect skin irritation and penetration. Pro-insect protection lasted up to a maximum of 8 hours. Repellents may contain substances that greatly irritate the eyes, so contact with eyes must be avoided. Some repellents can penetrate the skin. One of these is DEET, which can penetrate the skin up to 14 %. While essential oils can penetrate into the skin only up to 3 %. Essential oils also minimize skin irritation compared to DEET, which moderately irritates the skin.

Repellents should only be used on the exterior parts of the body.

  1. Don’t apply it to children under the age of 2 years.
  2. Never apply repellents on hands of children, because they are frequently in the contact with their mouth / eyes.
  3. Do not put in on your clothes.
  4. When we no longer need the repellent, we recommend showering with soap to remove the repellent from the skin as soon as possible, in order to avoid unwanted effects.
  5. If irritation occurs, the area must be rinsed with water and soap.
  6. The instructions must be followed closely.

If you can, avoid the hours when mosquitoes are active in order to prevent contact with them. If you want to go for a walk it is better to use repellents with essential oils, since they don’t irritate the skin so much and they also smell really nice.

You must have heard that hemp in cosmetics has positive effects on the skin. It is an increasingly popular ingredient for the treatment of skin diseases and the care of sensitive skin. Which parts of hemp are at all allowed for use in cosmetic products, what is CBD and what are cannabinoids, what effects does hemp in cosmetic products have on the skin?

Cannabidiol or CBD

First, we explain the basic terms. Cannabidiol is a phytocannabinoid that exhibits biological effects and acts against anxiety and nausea, and also has antitumour effects. Cannabidiol has no psychoactive effects. It has many positive effects on the skin, such as the ability to inhibit the formation of sebum and anti-inflammatory activity, as it inhibits immune responses to inflammation.

Cannabinoids

Cannabinoids were also proven to have anti-inflammatory and sebostatic (ability to inhibit the formation of sebum) properties. Cannabinoids are capable of inhibiting the maturation of keratinocytes, which is highly desirable in skin diseases, where the maturation of keratinocytes is abnormal, as in psoriasis and atopic dermatitis.

Endocannobinoids have psychotropic effects. THC is the only cannabinoid that is psychoactive, and there are still about 60 (according to some data, even 113) cannabinoids that do not show such effects.

Hemp seeds

In Chinese medicine and nutrition, hemp seeds have been used for more than 3000 years. Seeds are rich in vitamins A, C and E, and β-carotene, proteins (all essential amino acids), carbohydrates, fibers and minerals. The oil is obtained from seeds by cold pressing or by solvent extraction.

The seed also contain terpenoids and cannabidiol, which exhibit anti-inflammatory properties. The oil does not contain THC, unless it is present as an impurity. Concentration of THC in the oil depends on the cultivation itself and on the cleaning process. According to European legislation, the concentration of THC in oil must be less than 0,2%.

Fun Fact # 1: According to some data, Budha only ate cannabis seeds for 6 years. Seeds have an extremely nutritional value, thanks to proteins and unsaturated fatty acids.

Extract from cannabis seed

In the study on men,there was a cream containing 3% extract from hemp seed tested. After application of the cream with this extract, the secretion of sebum was significantly reduced. In men who had erythema, the redness decreased significantly.

What is hemp oil?

Marketing term for cannabis oil is the term “hempseed oil” so that it can be separated from cannabis used as a drug. Hemp oil is not obtained from leaves, but from cannabis seeds. This, of course, leads to the conclusion that hemp oil will not exhibit relaxation effects, as the seeds do not contain THC (tetrahydrocannabinol), except as mentioned above, as an impurity. THC is present only in cannabis leaves.

Fun Fact # 2: Cannabis with low THC value is estimated at $ 100-2000 million per year. What in the euro would mean about 90 – 1800 million euros. Crazy number, huh?

Composition of hemp oil

We have repeatedly mentioned the importance of oil composition. Hemp oil consists of all three of the most important fatty acids that act regenerative and / or antimicrobial. These fatty acids are very unstable because they contain double bonds that are highly reactive.

Linoleic acid – 57% (omega-6) is regenerative and anti-inflammatory

α-linolenic acid – 16% (omega-3) acts regeneratively

γ-linolenic acid – 3% (omega-6) acts anti-inflammatory

The ratio between linoleic and linolenic acid is 3: 1, which is the ideal ratio for dietary and cosmetic products. This oil can also serve as a natural source of antioxidants (vitamin E).

Atopic dermatitis and hemp?

Atopic skin has one disadvantage, namely, there is a defective action of δ-6-desaturase. It is responsible for the enzymatic conversion of linoleic acid into γ-linolenic. So, if desaturase does not work properly, we have an elevated level of linoleic acid, and the level of γ-linolenic acid is reduced. It is therefore desirable to use oils for the care of atopic skin, which also contain γ-linolenic acid, and thus add it itself because the skin itself does not produce it.

One of these oils is a hemp oil containing γ-linolenic acid. Due to the fatty acid composition, it helps to improve all skin diseases in which the skin barrier is weakened.

Studies also show the positive effects of cannabis on the skin

In Finland, a study was carried out in patients with atopic dermatitis, in which the test subjects orally used cold pressed hemp oil (30ml). They found that cold pressed hemp oil in an 8-week study, improved dryness of the skin and itching. The use of hemp oil reduced the use of topical medicines among test subjects. Olive oil was used as a control in which no such skin improvements were detected.

The endocannabinoid system in our skin

It is a biological system consisting of endocannabinoids. These are nonspecific lipid-binding carriers that bind to cannabinoid receptors and cannabinoid receptor proteins that are expressed in the central nervous system (including the brain) and peripheral nervous system. The endocannabinoid system is involved in the regulation of various physiological and other processes, including fertility, pregnancy, appetite, feeling of pain, mood and memory.

The effect on the endocannabinoid system would help to improve skin diseases such as psoriasis, atopic dermatitis, skin fibrosis, skin cancer, and itching.

What about hemp in cosmetic products?

In cosmetic products, oil from cannabis and hemp seed is allowed. Any extracts, tinctures and oils from flowers or fruits are prohibited. On the basis of the Regulation on cosmetic products no. 1223/2009 leaves and trunks are also prohibited. They belong to Annex II on cosmetic products where substances are prohibited in cosmetic products. On the list “Narcotics, natural and synthetic” we find cannabis resin, extracts and cannabis tinctures, which are also prohibited.

Sources:

Río, C. del, Millán, E., García, V., Appendino, G., DeMesa, J., & Muñoz, E. The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders. Biochemical Pharmacology 2018. 

Singh, D., Fisher, J., Shagalov, D., Varma, A., & Siegel, D. M. Dangerous plants in dermatology: Legal and controlled. Clinics in Dermatology 2018; 36(3): 399–419.

Dhadwal, G., & Kirchhof, M. G. The Risks and Benefits of Cannabis in the Dermatology Clinic. Journal of Cutaneous Medicine and Surgery 2017; 22(2): 194–199.

Pacher P, Bátkai S, Kunos G. The endocannabinoid system as an emerging target of pharmacotherapy. Pharmacol Rev. 2006; 58(3): 389–462.

Montserrat-de la Paz, S., Marín-Aguilar, F., García-Giménez, M. D., & Fernández-Arche, M. A. Hemp (Cannabis sativa L.) Seed Oil: Analytical and Phytochemical Characterization of the Unsaponifiable Fraction. Journal of Agricultural and Food Chemistry 2014; 62(5): 1105–1110.

Alcohols are on a bad voice, just like silicones and parabens. When we see an ingredient with an alcohol ending on the product, we automatically categorize it as bad. But can all products containing any kind of alcohol be declared as bad or are we just being too general?

What are alcohols and what is their function?

Alcohols are compounds having an -OH (hydroxyl) group attached to a carbon atom in the alkyl group. The group may be attached to a primary, secondary or tertiary C atom, so we separate primary, secondary and tertiary alcohols.

Primary alcohols include methanol, ethanol, isopropyl alcohol and others. Secondary alcohols include 1-propanol and 2-propanol and others. There are also alcohols with two, three or more -OH groups, which we call diols, triols, etc. Among the most famous poliols are glycerol, ethylene glycol, propylene glycol, erythriol, and others.

Alcohols have several functions in cosmetic products. They are mostly used as solvents or co-solvents, and in high concentrations they posess antimicrobial properties, and therefore products do not need a preservative.

“No alcohol” doesn’t mean no alcohol

For many years cosmetic manufacturers have marketed certain cosmetic products that do not contain ethyl alcohol (also known as ethanol, or grain alcohol) as “alcohol free”. However, “alcohols” are a large and diverse family of chemicals, with different names and a variety of effects on the skin. This can lead to some confusion among consumers when they check the ingredient listings on cosmetic labels to determine alcohol content.

In cosmetic labeling, the term “alcohol,” used by itself, refers to ethyl alcohol. Cosmetic products, including those labeled “alcohol free,” may contain other alcohols, such as cetyl, stearyl, cetearyl, or lanolin alcohol. These are known as fatty alcohols, and their effects on the skin are quite different from those of ethyl alcohol.

Should any alcohol be avoided?

When we think about “bad” alcohols, alcohol denat, ethanol, isopropyl alcohol and SD Alcohol (which means “specifically denatured alcohol”) are the first we think of. These alcohols are commonly used as solvents for cosmetically active ingredients that are insoluble in water. The use of these compounds in cosmetics leaves a cool feeling on the skin, as the alcohol evaporates faster than water, while giving the products a “light-weight” texture. They also help with the penetration of cosmetically active compounds into the skin. Everything okay until now, right? But these alcohols are reputable to irritate the skin and dry it.

Ethanol or ethyl alcohol

Ethanol is widely used in all types of products to which our skin is directly exposed. Scientific literature contains contradictory evidence of the safety of such topical alcohol applications.

Ethanol is known to improve the penetration of other substances and can be used in transdermal delivery systems. In his study, Bommannan found that ethanol enters the skin in vivo and removes measurable amounts of lipids from the surface of the skin. Removing the lipid layer can reduce the function of the skin barrier, which makes the skin more permeable. Because the skin is more permeable, a larger transepidermal loss of water and less hydration of the epidermis results in further skin dryness. Longer use can cause dry, leaking skin due to a reduced amount of lipids and moisture and also causes local inflammation.

Alcohol denat

Alcohol denat is an abbreviation for denatured alcohol, which is used in cosmetics and personal care products. Denatured alcohol is a denaturant containing ethanol. The usual denaturants in cosmetic products and personal care products are: denatonium benzoate, t-butyl alcohol, diethyl phthalate and methyl alcohol. The method of denaturing alcohol does not chemically change the ethanol molecule.

Denatured alcohol is generally noted as alcohol Denat or SD (especially denatured) alcohol.

It acts as anti-foaming agent, adstringent, antimicrobial agent and solvent. One of the main reasons for the use of denatured alcohol is its adstringent action. Adstringent is a substance that reduces the permeability of the mucous membrane or skin and capillaries, thereby reducing the inflammatory response and sensitivity to external influences. Adstringent interacts with certain functional groups, in particular sulfhydryl, on the surface of the proteins, and thus causes their precipitation. Adstringents cool the skin and cause temporary toning effect.

Use of denatured alcohol

Denatured alcohol is commonly used in acne treatment. The product containing denatured alcohol dries faster, which gives it a cooling effect and immediately degreases the skin. However alcohol-based products can actually encourage sebaceous glands to produce more oils, which causes the skin to become even oilier than before. Excessive sebum production combined with irritation that may be caused by denatured alcohol can lead to increased acne production.

In case of long-term use of skin care products containing high concentrations of denatured alcohol, dryness and irritation may occur. Denatured alcohol can also cause erosion of the surface layer of the skin, leading to a weakened skin barrier.

Denatured alcohol is common in post-shave products, where the skin needs an adstringent effect. Often it is also found in sunscreens because it is a good solvent for UV filters in plays a role in their distribution over the skin.

Isopropyl alcohol

Isopropyl alcohol or 2-propanol is a flammable liquid that is obtained from propylene. It is a solvent that acts as a anti-foaming agent, an adstrigent and a viscosity reduction agent.

A spray with an isopropyl alcohol concentration of 80.74% did not show any possibility of dermal sensitization in 9 human participants. In one of the studies, it has been shown that isopropyl alcohol strongly irritates the eyes of rabbits, at a concentration of 70% of the solution in water.

Isopropyl alcohol, which some consumers consider that dries skin, is rarely used in cosmetics.

Let’s not throw everyone in the same basket, not all alcohols are bad!

So, many products on the market are labeled ” free of alcohol ” and then a look at the INCI list reveals compounds that end with the name alcohol. Is this a trap? Should we throw a bad light on such products? No. Not all alcohols are bad. Many cosmetic alcohols, such as cetyl alcohol, stearyl alcohol, cetearyl alcohol, myristyl alcohol, behenyl alcohol and lanolinic alcohol, are also used in cosmetics.

These are long-chain aliphatic alcohols (usually between 12 and 18 carbon atoms), which are often used in lotions and creams. They serve as emollients, plasticisers, emulsion stabilizers, foam stabilizers and viscosity control agents.

Cetyl alcohol is used primarily as a softener to prevent drying and cracking of the skin due to its water binding ability.

What do you think about alcohols in cosmetics?

Sources: Lachenmeier DW. Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity. J Occup Med Toxicol., Final Report of the Safety Assessment of Alcohol Denat.,
Final Report on the Safety Assessment of Cetearyl Alcohol , Cetyl Alcohol , lsostearyl Alcohol , Myristyl Alcohol , and Behenyl Alcohol, FDA

Have you ever showered with a shower gel that gives such silky feeling that you don’t want to ever leave? Well, silicones are responsible for this feeling. Also silicones can be found in most primers. They are ˝guilty˝ for the smooth effect and we can’t blame them. #sorrynotsorry

What are silicones ?

Silicones are synthetic organic polymers of silicon. They can form silicones, silicates, silanes, or siloxanes. These can connect to larger molecules, which are normally flexible.

  Chemical structure State of matter
1. Silicone oils (dimethicones, cyclomethicone…) Liquids
2. Silicone waxes (alyildimethicones) Resins
3. Silicone emulsifiers (silicone polyether) Elastomers (dimethicones)

Approximately 85% of all silicones in cosmetic products are classified as silicone oils. That’s why we’ll give them a little more attention.

Silicone oils

Dimethicones

Dimethicones are waterproof ingredients, that distribute well over surfaces and are inert (they don’t react with other compounds). In one of the studies, more than 60 different dimethicones were observed to see which one is most common in cosmetic products. The most commonly found are dimethicone/vinyl dimethicone crospolymer (in 457 cosmetic products) and dimethicone crospolymer, which was present in 442 products.

Cyclomethycones

Cyclomethycones are volatile compounds, but they don’t leave a cold feeling while evaporating as ethanol does. They are odorless and non-toxic. Usually they are used as solvents or carrier systems for other silicones. With their incorporation into lipsticks, we can prolong their persistence.

Silicone waxes

Alkyldimethicones

Alkyldimethicones improve the compatibility of ingredients with oils and increase the stability of cosmetic products containing silicones. They work as moisturizers as well. They are used in many cosmetic products such as lipsticks, creams and lotions. They are very welcomed in suncreens since they are able to increase their effectivness.

When can we use silicones?

Silicones are safe and compatible (aren’t complicated and can get used to the new environment quickly). They are excellent ointments and lubricants, antifoams, emulsifiers, emollients and surfactants. Almost everything, right? But recently they are not that ˝in˝ anymore, since almost every package has a ˝without silicones˝ inscription.

Where can we use them?

Silicones are very common in decorative cosmetics and in skin care products. They are also found in products for children and products for sensitive skin, because they don’t irritate the skin. They are also suitable for application to deeper skin layers. Their origin isn’t animal so they are also suitable for vegans.

1. Hair: accelerated drying, increased shine, easier combing, regeneration

2. Give a good sensory feeling on the skin

3. Moisturizing (formation of a film that can beathe)

4. Skin protection (waterproof)

5. Cleaning ability (silicone powder – the ability to absorb lipophilic substances, including sebum)

6. Increase the effectiveness of active ingredients

7. Matting effect (for oily skin products, since silicones aren’t comedogenic)

8. Adhesion of pigments (used in primers under our make-up)

What are their advantages?

Silicones can get very well distributed and well smeared. They are surface-active (surfactants) substances that are colorless, tastless and odorless. Absence of color, taste and smell is very important in the formulation of cosmetics. They are inactive, temperaturely and chemically stable (they don’t interact with other substances).

Studies show that silicones are very safe for the consumer. They belong to the “Clean Beauty” substances. Clean Beauty is a platform where you can find safe products, they can be made of natural or synthetic materials. The point is, they are safe for the user.

Myths about silicones

“Silicones are toxic to nature because they rinse into rivers and seas.”

Health Canada has concluded that cyclomethicone (a type of silicone) has a low or no probability of environmental pollution and there is no necesity for any restrictions about the use of this substance. Very volatile silicones quickly evaporate and degrade in the air under the influence of the sun. Smaller quantities that remain in solid or liquid state are hydrolysed.

“We inhale silicones inhale and can be loaded in the lungs.”

Approximately 95-99% of the particles in sprays are bigger than 10 μm. According to the study, the particles inhabited by mistake are located and remain in the nasal cavity. They don’t go anywhere, regardless of the amount of silicones we inhale. So the chances of inhaling silicones, which can get and stay in the lungs is equal to almost 0.

“Silicones can clogg the pores.”

Silicones as substances aren’t occlusive (we still know what that means, right?), So they can’t clog the pores. They help to protect our epidermis and are also allowing our barrier to “breathe”. There are no reports proving that silicones irritate our skin, they actually do all the contrary, the feeling they leave is very ligh and soft.

However, due to the whole chaos, they are looking for alternative forms. Substances that are recently replacing silicones are olive oil derivatives, argan oil derivatives, coconut derivatives, alternatives to silicone elastomers, wheat sprouts.

In one study, however, it was confirmed that silicones pass the skin barrier and are loaded into epidermis. It’s expected to have negative effects on the epidermis, which we can see as a reduction of it. However, the whole study is imprecise, as they didn’t specify which parameters they took into consideration, so it’s difficult to be sure about the relevancy of this study.

Conclusion

If you are still afraid that the use of cosmetic products with silicone will clogg the pores, don’t worry, it won’t. Whether silicone compounds cross the skin barrier or not we know that such large compounds don’t cross neither healthy or damaged skin. Silicones have many advantages, even though they aren’t natural.

We already opened the shorts season, when travelling in Sicily and Morroco. And by this we opened the season of hairless legs. Hairs have their purpose to protect us from mechanical and thermal effects of the environment. But nowadays because of the impacts of the society and aesthetical reasons we remove the hair with several different depilation and epilation techniques.

Let’s get to know our hairs!

On our body there are two types of hair: fluffy and terminal. Terminal hairs are longer (more than 1mm), thicker, more pigmented, usually there is one hair for pilosebaceous unit and have longer life cycle. Fluffy hairs are shorter, thinner, there are more hairs growing in a pilosebaceous unit, are non pigmented and have a shorter life cycle.

Phases of hair growth

Hairs go through 3 different phases. First is anagen phase or phase of growth, that lasts approximately 6-8 years and depends on gender, age and health. Second is catagen phase or phase of transition – in this phase the growth in hair bulb starts shutting down and slowly stops. Last is the telogen phase is which the hair dies off, the hair bulb moves towards the surface and the hair falls out. When the last phase elapses, new cycle begins.

Photography: Neja Stojnič

Methods of hair removal

We know depilation and epilation techniques. And many people use this two terms wrong. With the term depilation we always think off removing hair with the wax, but this is wrong.

Depilation methods remove hairs without the effect on a hair bulb, the effect of depilation lasts around two weeks. Under the term depilation we count shaving and chemical depilation.

Epilation methods remove hair, including the bulb, the effect lasts around 6-8 weeks. Under term epilation we count waxing, pulling, laser methods and electrolysis.

Physical methods shaving, waxing, pulling hairs with tweezers, use of abrasives
Chemical methods chemical and enzymatic depilation

Shaving

We will not discuss this for long, like the effect of the shaving doesn’t last long (maybe 3 days). Shaving is the most popular method, because it’s fast, simple, cheap and the least painful. Hairs are removed only from the skin surface.

Shaving accelerates hair growth and makes them thicker.

Photography: Neja Stojnić

Waxing

Waxing counts as a epilation method. The effect last around 6-8 weeks.Waxing does not accelerate hair growth. For this methods hairs need to be at least 3mm long. It is unsuitable for diabetics and patients with vascular diseases. It can also cause some side effects like folliculitis, hyperpigmentation and scars.

Ingredients in waxing cosmetic products are usually: resin, bees wax, paraffinum, camphor, local anesthetics and ingredients with antibacterial effect.

Hot waxing is the process, where we heat up the wax and then apply it on the skin so it surrounds the hairs so they become a part of the wax. We remove the wax in the opposite direction of the hair growth. In cold waxing there is no need to heat up the wax.

Chemical methods of hair removal

Hair removing runs with chemical compounds and enzymes. The procedure happens without pain and it’s effects are visible for 2 weeks. Chemical compound penetrates in the hair cortex, where the reduction of disulphide bond in keratin happens. Simply, this means that the bonds that hold the hair together splits and this causes the hair to fall out. Hairs are removed on the skin surface or little underneath.

Active ingredients for hair removal
Active ingredientPropertiesSide effects
Sulfide (barium sulfide)– most effective
– strong unpleasant smell
Toxic for the skin, hair grows back into the skin
Sulfite– less irritation and absence of the strong smell
– ineffective
/
Mercaptans– methyl, butyl, benzyl-mercaptane have very strong smell
– less smell from polar mercaptans (tiolactic acid, tioglycolic acid) – slower but safer
Skin irritation, inflammation, chemical burns, scars
Photography: Neja Stojnić

Cosmetic products for depilation based on thioglycolates

First ever patented depilatory creams were based on thioglycolates and until today they still present a standard for chemical depilation. Most commonly used it calcium thioglycolate in combination with calcium hydroxide. A reversible reaction happens between hair keratin and alkaline thioglycolate. Depilation effect happens after 5-15min, pH rises above 10. These compounds are safe in concentrations up to 15%, show low systemic toxicity and are stable (in concentrations between 2,5-5%).

Side effects may be: skin irritation, inflammation, chemical burns and scars.

Laser hair removal

Discovery that lasers unspecifically destroy hair follicles was made more than 60 years ago. Laser enables selective photothermolysis – hair removal without damaging the surrounding tissue.

How does a laser work?

Exact certain wavelength of light and the duration of laser pulse leads to thermal damage of target tissue, that contains a chromophore. Melanin in hair follicle absorbs the laser light. Laser energy in the form of a light transforms into heat, that causes selective destruction of a hair follicle.

With this procedure the final destruction can be done to the hairs, that are in the moment of procedure in growth phase (5-15% of all body hairs), that’s why this procedure needs to be repeated (5-8 repetitions).

Nd:YAG laser

This laser can have a continuous source of light or pulse with wavelength of 1064nm. Melanin badly absorbs light with wavelength as high as this, that’s why this laser is ineffectual for permanent hair removal. Fast warming causes photomechanical damage to melanocytes in a hair bulb, wherein there is no damage done to the hair follicle. This is the safest and most efficient laser for dark skin (type IV). It only causes the delay of hair growth not the permanent removal.

Effectiveness of laser hair removal

One treatment only delays the hair growth for a short period of time. Before the treatment hairs need to be removed with shaving. While doing the treatments with the laser you should avoid exposure to the sun. Laser is the most effective on light skin with dark hairs, and not so effective with light or blonde hairs.

Fotografija: Neja Stojnić

IPL technology

IPL regulates the spectre of light with wavelength from 550nm to 1200nm with filters and so adjusts considering the skin phototype and hair color. More treatments lead to permanent hair removal. At IPL technology the light effects all the skin surface, not only hair follicles like the laser does. Because of this fact the risk of skin damage is higher with IPL. Effectiveness of IPL compared to laser is lower, because the energy is more scattered and is not concentrated just on the hair.

Nanoparticles are one of the latest threats to humankind. Almost. Certainly not in cosmetics. Nanoparticles don’t exist from yesterday, they have been here for quite some time. Only science, that studies them – nanotechnology is relatively new.

What are nanoparticles?

Nanoparticles are small units of material, that is smaller than 100nm. We know that nanometer is 10⁻⁹ right? Nanoparticles can come from a different origin: natural (desert dust), unintentionally produced (burning out biomass and fossil fuel), engineer (sunscreens and other cosmetics, textile).

Photography: Neja Stojnić

Why do we even use nanoparticles?

Nanoparticles exhibit new properties and functions of already known materials. This properties are very different than the properties from the same ingredients, but bigger order of size. Not only in cosmetics, but also in food technology and medicine they show a lot of advantages.

  • they stabilize and protect ingredients and extend the time of usage (fatty acids in oil, vitamins and antioxidants)
  • they affect  solubility and speed of solution of the ingredients
  • better activity on the skin
  • higher effectiveness and tolerance of UV filters
  • delivering cosmetic active ingredients in deeper layers of the skin

But everyone says, that nanoparticles are bad,..

Every good invention has a bad side, right? Nanoparticles can be toxic. Toxicity can be a consequence of damaging effects of decomposed products from nanoparticles. Physical properties of nano sized particles (big surface, charge), regardless the chemism of the products that compose nanoparticles, can be a reason for toxicity as well. Nanoparticles show unique physical-chemical properties because of their size. They can be more chemically reactive and can express higher biological activity.

Photography: Neja Stojnić
The connection between nanoparticles and unwanted effects

In the last few years the exposure to nanoparticles has risen because of development of different techonologies. Scientists have figured out, that this leads to a lot of unwanted effects on your health system. Connection was made between nanoparticles in the environment and unwanted effects of respiratory tract and cardiovascular system.

Special physical-chemical properties of nanomaterials lead to forming reactive oxygen species in cells. Reactive oxygen species (ROS) cause oxidative stress. Cells react to this kind of stress with inflammation. Research on rodents had shown that empty nanoparticles have a much higher inflammation effect on the unit of mass than bigger particles with the same chemism.

Inhalation of nanoparticles leads to loading in the lungs, they can also enter the bloodstream and brains. That’s why their use is forbidden in aerosols.

Now before you panic, close your computer and throw all of your sunscreens with nanoparticles away

Nanoparticles don’t work like that when applied to the skin. Our epidermis provides effective protection from effects of the environment. They can pass through the cells, hair follicles or sweat glands. But they don’t pass healthy skin. Damaged skin is another story, in this case the particles can pass the skin, but under what conditions remains unknown.

Why are mineral UV filters in sunscreens in nano size?

Mineral filters in their normal size (200-400nm for zinc oxide and 150-300nm for titanium dioxide) disperse really badly and because of that the application is difficult. They reflect and scatter the light and that causes an unwanted white layer on the skin surface. With the help of nanotechnology we are able to reduce the size of the parcticles under 100nm. With doing that we achieve easier application and transparency.

Photography: Neja Stojnić

Do nanoparticles cross the skin – main subject of scientists

There are a lot of arguments between scientists whether nano sized particles pass the skin barrier and what are the effects of penetrating into the deeper layers. Some studies prove them passing the skin and their toxic effects on the cells, while others disprove this theory.

There are many differences depending on the sort of the vehicle in which we include nanoparticles. Researches had shown that nanoparticles in mineral oil did not pass the skin, while the ones included in O/W emulsion (oil in water – usual for all the creams) did penetrate. Penetration was much higher in the area with a lot of hairs, which shows the penetration through the pores and hair glands.

The smaller the particles, the bigger the chance that they will penetrate the skin. There is a big difference between a particle that is 2nm big and particle that is 50nm big. As we mentioned before, the smaller the particles, the bigger the chance that their properties will change.

Does a regulative on cosmetic field protect us?

We’ll be honest, not really. Cosmetic producers are not obligated to tell what size of  nanoparticles are included in their products. They are obligated to write ‘’NANO’’ next to the filter that is in nano size, but whether this means particles 2nm or 100nm large no one knows, except them.

They represent a big progress in cosmetic industry

Usage of nanometer delivery vehicles is the future. Until now all the cosmetic products contained highly effective ingredients, that manufacturers bragged about. But whether this ingredient will achieve the wanted target in the skin was another thing. Only molecules smaller than 500Da can penetrate in the skin. And if we include a peptide with a molecular mass of 4000Da in our products, it will most certainly not penetrate in the skin. Nano delivery vehicles enable reducing these big molecules into smaller ones, so they can be included to the systems that will reach the target area. This delivery systems are liposomes, dendrimers, solid lipid nanoparticles,..

What is your opinion on nanoparticles in cosmetics?