Daily use of broad-spectrum sunscreen measurably reduces sun-induced skin ageing. The evidence is solid but rests largely on one large randomised trial, and common sunscreens still provide insufficient protection against long-wave UVA and visible light.
Yes, sunscreen demonstrably protects against sun-induced skin ageing, also known as photoageing. This refers to the changes that occur after years of exposure to UV radiation: wrinkles, age spots, a rough skin texture and loss of elasticity. The type of ageing differs by skin tone: people with lighter skin develop more wrinkles and loss of elasticity, while people with darker skin are more prone to pigmentation spots.
A randomised controlled trial in 903 Australian adults showed that daily use of broad-spectrum sunscreen led to 24% less increase in skin ageing after 4.5 years compared with people who used sunscreen only occasionally. Among daily users, there was no measurable increase in ageing at all. This is the strongest direct evidence for the protective effect of sunscreen in humans.
The main culprit behind photoageing is UVA radiation (wavelengths from 320 to 400 nm). UVA penetrates deeper into the skin than UVB, reaching the dermis (the deeper skin layer), and causes damage via reactive oxygen radicals. Broad-spectrum sunscreen protects against both UVA and UVB. An important point to note: most common sunscreens on the American market provide insufficient coverage against long-wave UVA (above 370 nm) and visible light, even though these also contribute to ageing and pigmentation problems.
Visible light and infrared light may also play a role in skin ageing and pigmentation, but the evidence for this is still limited. Moreover, there are no officially approved sun filters that specifically protect against visible light. Standard sunscreen therefore offers little benefit in this regard.
On the subject of safety: chemical UV filters in sunscreen can be absorbed through the skin and have been detected at measurable levels in the blood. However, clinical harm in humans has not been established to date. The scientific consensus still supports the use of sunscreen, but further research into long-term safety is ongoing. Anyone with concerns about chemical filters can opt for mineral alternatives (zinc oxide, titanium dioxide). Beta-carotene as a supplement has been shown to have no protective effect against photoageing and is not recommended as an alternative on the basis of the available data.
The key finding on daily sunscreen use comes from one randomised controlled trial (PMID 23732711, n=903). Other claims are based on review studies (PMID 34387824, 38772426, 39913224, 38924160, 40072791) and one study on plant-based antioxidants (PMID 33360043). No meta-analysis was used as a direct source.