What is the principle of sunscreen in cosmetics?

The principle of sunscreen in cosmetics is mainly to achieve the effect of sunscreen by adding sunscreen ingredients. Sunscreen ingredients are mainly divided into two categories: chemical sunscreen and physical sunscreen.

1. Chemical sunscreen: Chemical sunscreen can absorb ultraviolet rays and convert them into heat energy, thereby reducing the degree of ultraviolet radiation on the skin. Common chemical sunscreen agents include benzophenone, diethyl benzoate, and ultraviolet absorbers.

2. Physical sunscreen: Physical sunscreen mainly refers to granular substances such as zinc oxide and titanium dioxide, which can reflect, scatter, and absorb ultraviolet rays, thereby achieving the effect of sunscreen. Physical sunscreen has less skin irritation and higher safety when used.

The sun protection ingredients in cosmetics need to be selected based on different UV wavelengths, commonly including UVA and UVB protective ingredients. UVA is a longer wavelength ultraviolet light that can penetrate glass and cause significant damage to the skin; UVB is a type of ultraviolet light with a shorter wavelength that can cause diseases such as sunburn and skin cancer. Therefore, when choosing cosmetics and sunscreen products, it is necessary to choose sunscreen ingredients that have both UVA and UVB protective effects.