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.
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)
- 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.