UV Filters
UV (ultraviolet) filters in sun protection products are the active ingredients that prevent ultraviolet light from getting through to the skin.
Unprotected exposure to the sun’s rays can result in sunburn (erythema) mainly due to UVB rays but with a small contribution from UVA rays. The adverse effects of UVA rays include premature skin ageing, photosensitivity disorders and some forms of skin cancer.
The number of cases of skin cancer has increased considerably with the trend for people to expose their skin more to sunlight.
Sun products may contain several different UV filters to provide a broad spectrum of protection. Individual filters tend to be effective at different wavelengths of ultraviolet light.
Broadly speaking, there are two types of UV filter: organic and inorganic (mineral) filters.
The organic filters absorb the ultraviolet light and convert it into a small amount of heat. Organic filters are the most commonly used UV filters but they are often supplemented in products with inorganic filters to increase the efficacy.
Inorganic filters can reflect, scatter and absorb the UV light depending on the size of the particles. The absorption and also efficacy is increased when the size is smaller. When particle size is not sufficiently small there is a skin whitening effect and the products are less cosmetically acceptable. Inorganic filters protect against both UVA and UVB radiation.
For example, nanopigments such as titanium dioxide (TiO2) and zinc oxide (ZnO) are minerals that are used in some sunscreens as filters where they ensure protection of the skin. Moreover, their transparency facilitates usage and therefore acceptance by consumers.
UV filter safety testing
The safety of cosmetics is of paramount importance to cosmetic manufacturers, as well as being a requirement of the cosmetics legislation. All UV filters in sun protection products have to undergo a stringent safety assessment in accordance with the EU Cosmetics Directive before they can be used in cosmetic products on sale in Europe. The list of UV filters which cosmetic products may contain forms Annex VII of the EU Cosmetics Directive. This also sets out the limits and conditions under which the UV filters may be used. Any new UV filters must be approved by the European Commission’s Scientific Committee for Consumer Products (SCCP) before they can be added to the list. This requires submission of a comprehensive safety dossier.