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The importance of different UV filters in sunscreens

Not only sun creams, but also many other skin care products for the face come with UV protection. Chemical or mineral UV filters are used, but sometimes both are used together. But what is the difference and what makes a good UV protection?

UV filters minimize the undesirable effects of UV radiation on the skin and are therefore important ingredients in sunscreens. But everyday facial and hair care products also contain UV protection. The benefits are obvious: by protecting the skin from the sun’s harmful rays, the filters help to prevent premature skin aging and skin cancer.

What makes good UV protection?

Being photostable

Not all UV filters are equally good. For example, there are UV filters that are not photostable, i.e. they break down under UV radiation. As a result, the protective effect diminishes, and the decomposition products can also irritate the skin. Products based on octyl methoxycinnamate, for example, are not photostable – so always take a look at the list of ingredients.

Protect against UVA and UVB radiation

Also important to know: Manufacturers usually combine several UV filters in one product, since most UV filters do not protect against the entire UV spectrum. The combination of different filters should protect against both UVA and UVB radiation. UVB rays are those that cause sunburn, UVA rays are responsible for aging of the skin. The sun protection factor (SPF) indicated on sunscreens refers only to protection against UVB rays, so always make sure that the product also has an additional UVA seal. This indicates that the UVA protection is at least one third of the UVB protection. UVA protection is also called PPD, which stands for Persistent Pigment Darkening.

Avoid additives

The fewer fragrances and additives in the creams, the better. Additional substances can irritate the skin or cause allergic reactions.

Mineral or chemical – what is the difference?

In the case of UV filters, a distinction can be made between those based on organic chemicals and those based on mineral pigments, explains the German Cosmetic, Toiletry, Perfumery and Detergent Association (Industrieverband Körperpflege- und Waschmittel, IKW).

Chemical UV filters

Liquid chemical UV filters such as butylmethoxydibenzoylmethane absorb the radiation, convert it into heat and form an invisible protective shield in the upper skin layer. They are also known as organic UV filters.

Mineral UV filters

UV filters based on mineral pigments such as titanium dioxide and zinc oxide, on the other hand, reflect, scatter and absorb the sun’s rays on the surface of the skin. The small particles are visible on the skin, so you can easily see where you have already applied the cream. A somewhat annoying aspect is that the products often leave a white haze on the skin and are difficult to remove. Manufacturers are therefore increasingly using nanoparticles, i.e. particles that are as small as possible, to reduce the white haze.

Advantages and disadvantages of the different filters

Mineral UV filters have the advantage that they do not decompose and are considered to be well tolerated overall. Certified natural cosmetics must always be limited to mineral filters. The disadvantage of mineral UV filters, however, is the previously mentioned white film on the skin, and the solution to the problem, i.e. to rely on nanoparticles, is also controversial. There is the assumption that the particles are small enough to penetrate the body and damage the organism. However, there are no current studies that sufficiently support this thesis. Nevertheless, if you want to be on the safe side, you should avoid products with nanoparticles.

While mineral filters are considered to be well tolerated, a closer look should be taken at organic chemical filters. A look at the list of ingredients can reveal whether the product contains active ingredients that can irritate the skin or cause allergies. For example, filter substances such as octocrylene can have negative side effects. A French-American study from 2021 also suggests that products containing octorylene should be discarded after one year at the latest. The researchers were able to show that octorylene develops into the problematic molecule benzophenone after this time. This is suspected of being carcinogenic. However, if no questionable ingredients are contained in the creams, chemical filters are just as suitable as mineral ones. Another advantage of organic chemical products: They are easier to remove and therefore do not dry out the skin as much.