PhotoageingPhotoaging
Skin ageing driven by UV exposure rather than time alone.
Photoageing is the skin ageing caused by ultraviolet exposure, as distinct from the intrinsic ageing that happens with time regardless. It produces the pattern most people think of as looking older: deep wrinkles, leathery texture, uneven pigmentation, broken capillaries and loss of elasticity.
The mechanism is damage to the dermis. UVA penetrates deeply and degrades collagen and elastin while triggering enzymes that break down more of it; UVB does most of the damage to DNA in the upper layers and is the main driver of burning and skin cancer. Both contribute, and neither is blocked by window glass equally, which is why one sided facial ageing shows up in people who drive a lot.
The scale of it is easy to underestimate. Most of what is attributed to getting older is cumulative sun exposure, which is why skin on habitually covered areas looks so different from skin on the face and hands at the same age.
It is also preventable to a degree that few interventions match. A randomised trial in Australia found daily sunscreen use produced no detectable increase in skin ageing over four and a half years, while the group using it discretionarily aged measurably. That is a prevention result from an actual trial, which is rare in skincare.
Prevention beats correction by a wide margin. Retinoids have real evidence for improving established photoageing, and they work slowly and partially; sunscreen, shade and clothing stop the damage accumulating in the first place.
Tanning of any kind is the opposite of prevention. A tan is the visible result of DNA damage, sunbeds are classified by the WHO's cancer agency as carcinogenic to humans, and the idea of a protective base tan is both wrong and expensive.
In practice: daily broad spectrum protection on exposed skin, shade and clothing when the sun is strong, and a retinoid if you want to work on damage already done.