DermUV

Photoaging

Photoaging is the visible aging caused by chronic UV exposure — wrinkles, age spots, leathery texture, and broken capillaries.

Photoaging explained

Up to 90% of visible facial aging is attributable to UV (mostly UVA), per peer-reviewed dermatology literature. Daily broad-spectrum SPF 30+ is the single most effective anti-aging intervention.

Related terms

Terms related to Photoaging connect the UV and sunscreen topic cluster.

Related DermUV pages

Continue with reference material and live city UV forecasts.

How to read this Photoaging page

The UV index is a measure of erythemal (skin-reddening) irradiance, where each whole point equals 25 mW/m² of UV energy reaching the surface. That is why burn-time estimates fall roughly by half when the index doubles.

UV strength on this page follows solar elevation, ozone thickness, cloud cover, altitude, and surface reflection. Snow can bounce back most of the UV that hits it, water and sand far less, but all of them add to the dose skin receives.

Plan outdoor blocks around the peak UV window, usually between 10am and 4pm local time. Shade, UPF fabric, a wide-brim hat, and UV-blocking sunglasses reduce dose more reliably than sunscreen alone.

Cloud cover is not protection. Thin or broken cloud can still pass most incoming UV, and light cloud edges can briefly scatter more UV toward the ground than a clear sky.

Cumulative dose drives photoaging and long-term skin damage more than any single day. Small daily exposures on commutes, walks, and driving add up across a season.

UV scale reference

The WHO scale groups UV 1-2 as low, 3-5 as moderate, 6-7 as high, 8-10 as very high, and 11 or above as extreme. Protection is recommended from UV 3 upward, and shade during the middle of the day becomes the priority from UV 8 upward.

A practical routine at moderate-to-high UV is roughly one ounce of broad-spectrum sunscreen for full-body coverage, applied 15 minutes before going out, then reapplied on schedule. Clothing, hats, and shade carry the rest of the load, especially for children and anyone with a history of easy burning.

Keep exploring DermUV

These pages give more depth around photoaging, from UV-scale reference material to definitions and city forecasts.

All figures on DermUV are educational estimates built from public UV data and published dose literature. They are not personal advice.