What Is Photodamage?
Photodamage (photoageing) refers to the cumulative structural and functional changes in skin caused by chronic ultraviolet radiation exposure over years and decades. Unlike chronological (intrinsic) ageing, which affects all skin regardless of UV exposure, photodamage is largely preventable. It accounts for approximately 80–90% of visible facial ageing signs — wrinkles, laxity, hyperpigmentation, rough texture, visible capillaries, and sallowness — according to twin studies comparing UV-protected versus UV-exposed identical twins.
UVA vs. UVB in Photodamage
UVA (320–400nm) penetrates deep into the dermis. It generates free radicals that degrade collagen and elastin, causes DNA mutations (primarily cyclobutane pyrimidine dimers via indirect oxidative mechanisms), drives pigmentation irregularities, and is present at consistent intensity year-round regardless of cloud cover. UVB (280–320nm) is more energetic, causes direct DNA damage (sunburn is UVB-mediated), and is the primary driver of squamous and basal cell carcinomas. Both cause melanoma risk and require broad-spectrum SPF coverage.
Treatment Options
Retinoids (topical tretinoin) are the most evidence-backed reversal treatment for photodamage — they stimulate collagen synthesis, normalise epidermal architecture, and fade pigmentation. Antioxidants reduce ongoing ROS damage. Chemical peels and laser resurfacing can address surface texture and pigmentation. Prevention via daily broad-spectrum SPF 50+ applied generously (2mg/cm²) remains dramatically more effective than any corrective treatment.
Prevention ROI: Daily SPF applied consistently from age 18–40 can prevent the equivalent of decades of photoageing. No corrective treatment achieves equivalent results. Starting SPF at any age still meaningfully slows further damage accumulation.
See Sun Filters and UVA & UVB.