We’ve already gone through basics about UV rays, protection against UV rays and everyday use of sunscreen. Now it’s time to take a look in the world of compounds that protect us from UV rays – UV filters.

There are two types of UV filters

Organic or chemical and inorganic or physical UV filters. Physical filters scatter and reflect UV rays, while chemical filters absorb them. Physical filters leave a white residue (unless they are nano size), while chemical filters spread quite smoothly.

Sunscreens are usually a mixture of different chemical and physical filters, because with combining them we achieve a broad spectrum protection.

There are even more UV filters then we mentioned in a previous post, so we asked members of a Slovenian Facebook group Ljubim kozmetike to mark the most common filters in their sunscreens. We are going to describe 4 most common ones.

Organic UV filters

Data from studies shows, that organic filters are present in most sunscreens on the market. The most common organic filter is Ethylhexyl methoxycinnamate, since it is present in 80% of all sunscreens. Chemical filters easily absorb in the skin and reach blood circulation. Consequently they can load in different tissues, liver and brain.

Ethylhexyl methoxycinnamate

Oktyl metoxycinnamate (OMC) is a UVB filter known as 2-ethylhexyl-4-metoxycinnamate. As a compound it is allowed for usage in cosmetic products in United States and Europe in concentrations between 7.5-10%. Lots of studies suggest that OMC in an endocrine disruptor, because it can affect excretion of hormones.

After applying of cream with 10% concentration of OMC on the whole body (40g), the filter was absorbed in the skin and was later found in urine and blood. But if we take the highest measured concentration, the complete concentration in 4.7L of blood was only 0.002%.

The positive side of this filter is that it does not irritate the skin and does not cause sensibilisation.

Ethylhexyl salicylate or oktyl salicylate

It’s a organic UVB filter, that absorbs the UV rays. It is allowed for usage in cosmetic products in concentrations up to 5%. This is a filter with relatively good safety profile. Ethylhexyl salicylate possesses an ability to stabilize other photolabile (sensitive to light) UV filters and make them longer lasting. Quite a guy, ha?

This filter has a really low toxic profile. It does not cause irritation or sensibilization, it is not phototoxic and does not cause foto-allergies.

Inorganic UV filters

Inorganic filters used in sunscreens usually contain metal oxide particles, for example titanium dioxide and zinc oxide. These two can be used in concentrations up do 25%, but are usually contained in lower concentration – between 5-10%.

Chemical filters are still dominant in sun-protection products, but the number of products containing only physical filters is rising. One of the reasons why is the fact that they offer a broad spectrum protection – TiO₂ is more successful protection from UVB range, while ZnO is more successful at protection from UVA and UVB1 rays (the protection for UVB range is lower). Using these both filters together provides a broad spectrum protection. Another positive side of using physical filters is absence of irritation and limited skin penetration.

Zinc oxide

Dermal absorption is the main route of entrance for ZnO nanoparticles in our system. Most studies showed that ZnO particles don’t penetrate in deeper layers of the skin. Penetration is significantly higher when the skin barrier is damaged.

Titanium dioxide

Titanium dioxide is commonly used as a white pigment in colors, plastic and paper and as an additive in food. Nanoparticles of TiO₂ are used because of the capability to absorb the UV light in sunscreen products. TiO₂ particles have very low toxicity.

Nanoparticles of TiO₂ can be used in sunscreen products in concentrations up to 25%. Studies show that particles of this filter don’t penetrate healthy or damaged skin. In human keratinocytes it exhibited almost no cytotoxicity, which suggest a very small toxic potential on the skin level.

Exposure to UV filters

We are most exposed to UV filters in a dermal way. Suggested application of sunscreen is 2mg/cm² skin, so that we would reach the protection factor listed on the product. This means we would have to use the whole 40g cream to protect the whole body. At this amount of product, the maximum penetration would be 5% for some organic UV filters. Studies show that amount of product applied is much lower than suggested (less than half). So if we apply a product with SPF 50, the real protection will be probably 25 or less.

UV filters offer a protection from erythema, actinic keratosis and carcinoma. There is also data that sunscreens block normal synthesis of vitamin D and that they act as endocrine disruptors. But in normal usage this is not the case.

What can we conclude?

Usage of UV filters is questionable from aspect of safety. More and more studies show the link between bigger usage of sunscreen products and phenomenon of hormonal and growth disorders. At this point you need to realize that in studies they work with much higher concentrations than allowed. With cosmetic products it is impossible to come in touch with such high concentrations. But we can’t just ignore what the studies say, because side effects can occur within sensitive population. Effects of being exposed to low doses of UV filters for a long period of time are pretty much unknown. Scientists should investigate further and try to find safer compounds to protect us from UV rays.


Sunscreen is essential for preventing skin diseases and premature aging. In conclusion: sunscreen should be used in every season. However, experts started to warn about the importance of protection against UV, but that happened only a few years ago.

There are several types of electromagnetic radiation and one of them is UV radiation. Ultraviolet radiation consists of 3 wavelengths: UVA rays (emitting a wavelength from 320 to 400nm and aren’t absorbed by the ozone), UVB rays (the wavelength from 290 to 320nm, partially absorbed by ozone) and UVC rays (are stopped by ozone) -> well, what’s still left from ozone.

UV radiation has some beneficial effects, such as vitamin D synthesis. It also has a positive effects on the treatment of dermatological problems (acne, psoriasis), bone and joint disorders and childhood diseases. However, there are more negative effects (role in pathogenesis of skin cancer, photo-aging and photo-immunosuppression) than positive.

 UVAUVB
Acute effectsImmediate pigmentation, photosensibilisationErythema, edema, pigment darkening, thicker epidermis, synthesis of vitamin D
Chronic effectsPhoto-aging, immunotoxicityPhotocarcinogenesis, immunotoxicity

UVA rays

UVA rays represent the largest part of solar radiation. They stimulate the formation of reactive oxygen species or ROS. We’ve already been writing about it in blogs (Vitamin C and After 25th, we begin to grow old). UVA rays increase the number of inflammatory cells and reduce the activity of Langerhans cells, which are the first line of defense of our immune system.

UVB rays

UVB radiation causes sunburn. It represents about 18% of total solar radiation and it’s 50-100x stronger than UVA radiation. Our DNA molecules absorb UVB light very well, which can lead to mutation and carcinogenesis. They can damage biomolecules (proteins, lipids and DNA molecules).

UV rays don’t rest!

A few days ago, we’ve asked on Instagram story some questions about your habits regarding to sunscreens and their usage.

57% use the sunscreen only on the beach

56% prefer using sunscreen with a very high protection factor (50, 50+)

69% apply sunscreen several times a day

22% avoids nanoparticles in sunscreens

It’s a bit worrying that more than half of you use sunscreen only at the beach. It’s true that in winter the sun is significantly weaker comparing to summer, but this doesn’t necessarily mean there are no UV rays. In winter while it’s snowing it’s even more likely to get sunburned, because UV rays reflects from snow (white colour reflects sun rays). Despite the fact that there are clouds, who says UV rays can’t pass these clouds to get to us? Again, not so much, but they pass through. Have you ever heard of a friend who went hiking ant the weather was cloudy and came home as red as a beet? Because we have! So this means that UV rays exists even on a cloudy day.

Why is re-application necessary?

Probably, the ones who had answered that apply sunscreen only once, are asking themselves what the hell? You have applied the cream, okay. So you don’t sweat or touch your face? Consequently, by touching and sweating you remove the cream. Also, UV filters stop working after a certain amount of time, meaning they no longer have the effect of protection.

Sun protection products

The main purpose of sunscreens is to protect the skin against the harmful effects of UV radiation. But in order to achieve this effect, it takes more than just choosing the right UV filter in the appropriate concentration. One of the important things is also technological formulation and other ingredients which can support the effect of UV filter or can decompose it.

There is currently a flood of sunscreen products on the market. The SPFs are from 1-50 +. There are products with low protection (SPF 6-10), medium protection (SPF 15, 20, 25), high protection (SPF 30, 50) and very high protection (50+). According to European standards, UVA protection must represent at least 1/3 of the declared SPF.

Recently, we have seen the SPF mark on almost all face products, whether it’s decorative or nourishing. It is especially popular that UV filters are added to the powders, BB and CC creams.

What’s the problem of foundation with SPF15?

If you didn’t just come from the Stone Age, you probably know that for a SPF written on packaging, the application must be 2mg / cm². You probably don’t know how much of sunscreen that is. For a face it is supposed to be used 2 full fingers of cream. We are not 100% sure, but somewhere we’ve found that 70kg man has to use almost the whole sunscreen in order to achieve the SPF protection written on the packaging. Is this even possible? Not really.

Because of the incorrect or insufficient amount (usually 0.8 mg/cm²) of the sunscreen, the actual SPF on our skin is only 20 to 50% of SPF declared on the packaging. So, when using foundation with SPF15, we usually apply a pump or two. This means the actual SPF on the skin is probably barely 3, if not less.

SPF 30 vs. SPF 50

I think that most of us, who have been more or less introduced to the protection against UV rays, know this graph.

This graph shows us that with the protection factor 30, we achieve approximately 95% of protection against UVB rays. With a protection factor of 50, approximately 96.5% of protection. Experts are arguing whether this 1.5% makes a big difference. We must be aware of the amount of UV filters that must be incorporated into the product with SPF 50 comparing to SPF 30. This increased quantity may be unfavorable for people with photosensitivity disorders. If you don’t have them, it’s up to you, if you want to use higher or lower SPF. Keep in mind that you are likely to apply less product and the actual protection is lower.

Types of UV filters

Currently, two types of UV filters are in use, physical and chemical, both of them minimize the previously listed effects of exposure to UV radiation.

Physical or inorganic filters disperse and reflect UV rays while chemical or organic filters absorb them. More and more studies assess the role of these compounds in developmental and endocrine abnormalities, which have been demonstrated in animal and human studies.

Organic UV-absorbing filters are divided into: PABA derivates (PABA, ethylhexyldimethyl PABA), cinnamic acid derivates (ethylhexylmethoxycinnamate, octylmethoxycinnamate), salicylic acid derivates (homosalate), octocrylene, triazine derivates (ethylhexyl triazone), benzophenone derivates (oxybenzone BP-3), sulisobenzone) and dibenzoylmethane derivates.

Among the physical UV filters that reflect and disperse UV rays are zinc oxide and titanium dioxide. Sunscreens are mostly a mixture of several organic and physical UV filters, because with the combination we achieve broad spectrum protection.

After we pass 25 our skin starts ageing, not only skin but the whole body. Horror! We are not even close to half of our life but we are already ageing. The process of ageing is very complex. But it is up to us whether we speed it up or slow it down. We vote for slowing it down, how about you?

What is ageing?

Ageing is a genetically caused process, where degenerative (decompositions) changes take over the regenerative (building) changes. Very simply imagine taking apart lego cubes faster than building them back. If we are consistent we will break down all the cubes. And the same goes for the skin if we don’t take care of it properly. Besides the genetics, hormones also play a role in ageing. First there are morphological changes, only after that we start seeing visible changes.

First let’s take a look at morphological changes

Changes happen in more skin layers. In epidermis there are some subtle changes, meanwhile dermis is going through more intense changes. Changes don’t happen overnight, and especially not all at once. When you are in your 30’es some changes are happening in your upper skin layers, and very little is happening in deeper skin layers.

Changes in epidermis

  1. Lower water content in stratum corneum – leads to drier skin
  2. Lower number of the cells, especially melanocytes and corneocytes (cells become bigger and have troubles replicating)
  3. Longer cycle of skin renewal, which is normally 28 days long (bigger keratinocytes are harder to remove, the result is rougher skin)

Changes in dermis

Of Course changes in your 30. are not so drastic as in your 50., but something is still happening.

  1. Thickness of dermis is constantly decreasing (1% per year)
  2. Skin elasticity is decreasing due to lower content of collagen and elastin
  3. Lower amount of glycosaminoglycans and hyaluronic acid
  4. Lower number of sebaceous and sweat glands

Consequnce of thinner dermis, lower amount of collagen, elastin and hyaluronic acid is occurence of small fine wrinkles. Especially between the eyes and between nose and mouth.

There is more than one type of ageing. Photoageing can be slowed down.

Photo Ageing is the type of ageing that is influenced by external factors, most commonly UV light. Smoking, wind, polluted air aid as well. Photoageing speeds up the chronological ageing. Run for your life, ok kidding.

Photoageing is connected with increased amount of radicals (ROS), that are formed in the body because of the increased production or inability to remove them. Radicals damage proteins, lipids and DNK.

This type of ageing makes more obvious changes

  1. Faster thinning of dermis and lowering the amount of collagen
  2. Damage in stratum corneum and changes in skin barrier
  3. Higher and faster enzyme activity – matrix metalloproteinase (MMP) starts to function. This enzymes affect the integrity of extracellular matrix. MMP decompose components of the matrix (collagen, elastin) and lower the skin firmness and elasticity. This enzymes are activated under the UV light.

The most obvious signs of photoaged skin are deep wrinkles, occurence of hyperpigmentation, changes in skin texture, extended capillaries and teleangiectazii. There is a possibility of cell proliferation and occurrence of tumors.

As we see photoageing affects the chronological ageing and this process can be slowed down.

Active cosmetics for slowing down the skin ageing

Slowing down the ageing can be done in more ways. The most common are:

-acceleration of moisture

-acceleration of peeling

-stimulating synthesis of collagen and elastin

-substituting hyaluronic acid

Here are one of the most important cosmetics active ingredients that we use for slowing down this process. Antioxidants are important as well.

Retinoids

Retinoids are natural or synthetic ingredients. They are derivates of all-trans retinoic acid or vitamin A. They are famous for their anti-ageing effects. Not only they regulate growth of epitel cells and their differenciation, but they also normalize the process of keratinization. Are the effects visible? Yes, the skin is smoother and wrinkles look smaller.

Tretionin (all-trans retinoic acid) is a golden standard. Clinical studies prove it’s effectiveness already at very low concentrations. Tretionin stimulates formation of collagen, reduces hyperpigmentation and reduces skin roughness. BUT, it is prohibited for use in cosmetic products. So, back to the beggining.

In cosmetics manufacturers use retinol that thickens epidermis. Studies show increasing amount of proteins and collagen in the skin. It is safe in concentrations up to 1%. To get the maximum effect on the skin it needs to convert to retinoic acid, but for this effect higher concentrations are needed.

There are also other forms of vitamin A like retinylpalmitate, retinylacetate, retinal and other much less effective forms.

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Boost of moisture

We already discussed all about cosmetic humectants. As moisturizers we can also use hydroxy acids (AHA, BHA, PHA). Fun fact that many people don’t know about is that hydroxy acids don’t only possess a exfoliating effect, but also a moisturising one. In low concentrations they stimulate renewal of epidermis, influence the collagen synthesis and have a moisturising effect.

For moisturizing we can also use hyaluronic acid, that binds the mass of water, that is 1000x bigger than her own mass. Penetration in the skin depends on the molecular mass.

How about lightening pigmentation marks?

The golden standard for treatment of the sunspots is hydroquinone, that is forbidden in Europe. But we can always use the alternatives such as azelaic acid, kojic acid, arbutin and other ingredients that inhibit enzyme tyrosinase, that takes part in melanin synthesis.

The most important step you can take is to protect your skin with everyday use of sunscreen. Even if there are clouds and snow outside. UV rays are always there.

Did you know that vitamin E is so unstable that it may not remain in the product/formulation? Probably his “working age” is gone before using a product. In this blog post we’ll ˝give˝ you vitamin E with all its advantages and disadvantages.

The basics about vitamin E

First, let’s look at the basics, even though we already know them. Vitamin E is an antioxidant. Antioxidant is any substance that, at low concentrations, reduces or prevents the effects of radicals. The main purpose of vitamin E is to delay or prevent the oxidation of sensitive compounds in the product. It provides defense against reactive oxygen compounds. If we don’t provide protection against reactive oxygen compounds, the cosmetic product can decompose and cause premature aging or/and DNA damaging.

We already have explained antioxidants and radicals in a post about vitamin C, if you have any doubts go to the post, to make clear, what we are talking about.

Unlike vitamin C, tocopherol is a lipid-soluble vitamin. It acts as a free radical catcher in lipophilic parts of the cell. Effective antioxidants are usually unstable because they are highly reactive. Vitamin E is for example very sensitive to UV light. So if we aren’t careful enough and we don’t store it in dark packaging, there is a chance that it will no longer be ˝successful˝ in the tasks that it has by the time we need it.

What types of vitamin E exist?

First, we can differ between tocopherols and tocotrienols. They differ in the application and percentage, which is allowed to be incorporated into a cosmetic product. There are four different forms of each: α, β, γ, and δ. So in total 8 different forms of vitamin E.

SortTocopherolTocotrienol
Role in cosmetic productsAO, smoothing, maskingStabilizer, in oral hygiene products, skin smoothing
% allowed in cosmetic products5,4%0,12%

What positive features does vitamin E show on the skin?

• smoothes fine wrinkles caused by photo ageing

• humectant

• after application the skin is softer and smoother (smoothing effect)

• few side effects because it forms a part of our body (if we add it to the skin, it recognizes our body for its own)

• accelerates wound/scar healing

• inhibits inflammation

• reduces damage caused by UV light

• protects our skin against harmful chemical substances

In cosmetics it’s used in concentrations from 1 to 5%. Normally we use vitamins E esters because they are more stable and better soluble in formulations. For example, tocopheryl succinate and tocopheryl acetate are the most used. Tocopheryl acetate is allowed in products up to 36%. Tocopheryl acetate has another good property it’s not phototoxic. What does that mean? If the substances are phototoxic, it means that if we go to the sun, the sun will burn us even more and leave the consequences for a longer period of time.

Natural presence of vitamin E?

Tocopherol is found in seeds, fruits and latex. Oils with the largest amounts of vitamin E are: oil of pomegranate and sea buckthorn oil. It’s also found in sunflower, peanut, walnut, sesame and olive oil. Palm oil is one of the richest sources of tocotrienols and it’s also found in coconut oil, cocoa butter and soy. However in cosmetic products we need to add extra amounts of vitamin E, since its content in oils isn’t sufficient to provide a good antioxidant role.

The permanence of vitamin E dependents on the fatty-acid composition of the oils (especially unsaturated fatty acids – those with double bonds, which can be oxidized very fast).

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How do we isolate it?

Tocopherol is isolated from vegetable oils (natural tocopherol). Tocotrienols can be isolated from the vine and oats. Alternatively, it can be obtained by other synthetic methods.

How does vitamin E come to cells?

Do you remember when we mentioned keratinocytes (epidermis cells) in skin composition? Well, vitamin E is also stored in keratinocytes, which are moved while the process of keratinization to the surface of the skin. So vitamin E ˝travels˝ with them. Another possible way is that vitamin E comes on the surface of the skin with sebum, since vitamin E is also secreted by the sebaceous glands. Why did we complicate things?

The activity of sebaceous glands begins to decrease after 50 years in women and after 70 years in men. And what do we usually do if something is running out of our body? Yeah, let’s help our body. The application of vitamin E shows positive effects for our skin and that’s delayed aging. Of course, it doesn’t prevent it, just to be clear.

What about metabolism?

α-tocopherol incorporates into lipoproteins (VLDL), these allow the distribution of this form of tocopherol over the body. Other forms pass into the bloodstream and are rapidly metabolized and secreted from the body. That’s why in skin can be found a lot higher amounts of α-tocopherol and very small amounts of γ-tocopherol.

Vitamin E is another indispensable ingredient in the cosmetics industry. Manufacturers incorporate it in oils and butters to prevent their oxidation. It can also be a MUST in your skincare routine, now that you know its positive effects, we believe that you will at least consider including vitamin E in your routine.