Does sunscreen prevent skin ageing?

Continuous exposure to UVA and UVB rays is responsible for the photoaging of the skin. In other words, UV exposure causes the skin to age more rapidly than it would naturally. Although it is difficult to completely avoid the sun's UV light, certain preventive measures for photoaged skin can be taken to limit exposure to UV rays and thus delay the skin aging process, the most common of which is the daily application of a broad-spectrum sunscreen with an SPF of 30 or more on exposed parts.

Exposure to UV rays is responsible for over 90% of visible signs of ageing, including wrinkles, roughness, loss of elasticity, skin dryness, and irregular pigmentation.

Whilst cleansers, moisturisers, and exfoliants are important products for limiting skin damage, nothing can replace the daily necessity of using a sunscreen with an SPF of at least 30 every day, whether the sun is shining or it's raining and regardless of one'sage.

There is a wealth of experimental evidence suggesting that sunscreen has effects on photoaging, however, this phenomenon has only been proven to date in hairless mice. Only one clinical study on humans has demonstrated this. In 2013, Australian researchers conducted the first controlled and randomised trial on 903 Australian men and women to assess whether sunscreen or oral antioxidant supplementation can effectively prevent the progression of skin ageing in adults under 55 years old. The participants were randomly divided into four groups:

1. Those who are advised to apply a broad-spectrum sunscreen with an SPF 15 to their face, neck, arms and hands every morning and to reapply after sweating profusely, swimming, or spending more than a few hours outdoors;

2. Those who could apply the same sunscreen whenever they wished;

3. Those who received a tablet of β-carotene each day ;

4. Those who received a placebo tablet.

After four and a half years, researchers analysed the silicone impressions taken from the back of the left hand of the subjects. They found that the group who used a broad-spectrum sunscreen daily showed "no detectable increase" in skin ageing after 4.5 years. Furthermore, skin ageing over the course of the study was 24% lower in the subjects of the group who received a sunscreen every day compared to the subjects who applied a sun protection product optionally. On the other hand, supplementation with β-carotene overall had no effect on skin ageing.

The sunscreens are products that combine various sun filters (organic and inorganic) that protect the skin by absorbing, blocking or diffusing harmful UV rays.

This initial human clinical trial proves that daily use of a sunscreen significantly slows down photoaging. To prevent accelerating the skin ageing process, the daily application of a broad-spectrum sunscreen with a minimum SPF of 30 in generous amounts and frequent reapplication, especially after swimming or activities that make you sweat, are highly recommended.