What is SPF factor? UV radiation has harmuff effects on the skin causing its premature aging, damaging the DNA of skin cells or eye cells. Getting sunburnt increases the risk of skin cancer.
Photoprotection inhibits the effects of UVA and UVB rays, reducing the possibility of carcinogenic damage to the skin, and includes sunscreens, clothing, sunglasses, hats, and windshields. Sunscreen emulsions are the primary protection of the skin from the sun and can be divided into physical sunscreens (repelling the rays) and chemical sunscreens (absorbing the rays).
Chemical sunscreens are based on substances that have greater ability to absorb solar radiation. Each chemical ingredient of sunscreen emulsions has a different capacity of absorbing different wavelengths of UV radiation, and the better ones provide both UVB and UVA protection. They can completely block UVB rays that are responsible for skin burning as well as for the development of skin cancer. When it comes to UVA rays they can be blocked entirely, or only partially, depending on the chemical substances used. UVA radiation is what makes our skin tan but it also causes our skin to age and it breaks DNA strands.
Physical components of sunscreens emulsions have similar effect as wardrobe. They completely block UVB rays as well as UVA rays of longer or shorter wavelengths depending on the ingredients used (titanium dioxide, talc, magnesium oxide, zinc oxide).
Antioxidants added to these emulsions include: Vitamin C, Vitamin E, Silymarin, green tea…
What is SPF factor?
SPF (Sun Protective Factor) represents how much UV radiation is required to produce sunburn on protected skin relative to the amount of UV radiation required to produce sunburn on unprotected skin.
This means that if the product is marked SPF 50, then the skin protected by this emulsion can receive 50 times longer UVB exposure than unprotected skin.
Four hours following the application, the protection is reduced up to 50%.
It should be noted that the label “waterproof” is not yet adequately regulated.
Side effects of sunscreen application include allergy, phototoxicity, irritation, as well as photoallergy.
Earlobes, hands, feet are the parts of the body that most often remain unprotected from UV radiation.
Also, any tanning of the skin implies sun damage to the skin to a lesser or higher extent. Any redness means that the skin is sunburnt and the development of blisters dramatically increases the possibility of developing skin cancer.
Appropriate application of sunscreens is crucial in photoprotection. Apply 2mg per cm2 of body surface. It should be applied 15 minutes before sun exposure and repeated after each sweating, bathing or every two hours.
Full UVA and UVB rays blocking is possible only with SPF 30 or more.
dr Svetlana Đurišić
References:
- A Study on the Factors that Influence the Sun Protection Factor(SPF) and Protection Factor of UV-A(PA) in Sunscreen
- Study to Evaluate the Sun Protection Factor (SPF) of Sunscreen Products
- Sun Protection Factor
image: racim amr
