It must be remembered that besides the beneficial effects, ultraviolet also has a number of negative effects
But, besides the beneficial effects, ultraviolet also has a number of negative effects – it destroys DNA molecules and cell membranes. The skin becomes tougher, the stratum corneum thickens. Type A rays penetrate deep into the skin, leaving no visible traces. Type B rays, on the other hand, cause sunburn.
To protect human skin from the negative effects of ultraviolet radiation, physical and chemical UV filters are used. Physical filters prevent the penetration of UV rays by screening. They often contain solid substances ground to a powder. The most popular are zinc oxide, silicone derivatives, titanium dioxides.
In the field of medicine, new inventions constantly emerge. Scientists have not ignored sunscreens either. The latest physical filters are made from micronized powders. After using such preparations, no whitish film appears on the skin. In primitive filters, the cream is absorbed into the body, and the remaining powder rolls off the skin's surface.
Chemical filters are designed to absorb UV rays and convert solar energy into heat. The most widespread are filters based on cinnamates, benzoquinones, and salicylic acid esters. Scientifically, physical and chemical preparations should be combined. This reduces the concentration of substances without affecting effectiveness.
The degree of protection depends on the SPF value. For the skin, SPF is a kind of radioactivity indicator that determines the safe duration of sun exposure. A high SPF value does not guarantee 100% protection. For example, SPF-10 ensures filtration of 90% of radiation, SPF-20 – 95%. However, highly concentrated preparations have a negative effect on the skin.
It is recommended to use two sunscreens – with SPF 10 and 25. The latter is used during the first exposure to the blazing sun, then you should switch to a weaker concentration. Everyone's skin is individual – any manufacturer's recommendations should be tested on yourself.
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