Photoprotection

Sunscreen (SPF)

Broad-spectrum sunscreen (SPF 30–50+) is the most evidence-backed intervention for preventing photoageing, hyperpigmentation, and skin cancer. It protects the results of every other active in your routine. There is no close second.

topicalanti-ageingUV protectionbeginner-friendly

Strong Evidence

Last reviewed: March 2026 · Our methodology

What It Does

Sunscreen filters absorb or reflect ultraviolet radiation before it penetrates the skin. UV radiation causes direct DNA damage (UVB → sunburn, DNA mutations, skin cancer), indirect oxidative damage (UVA → collagen degradation, photoageing, pigmentation), and immune suppression in the skin.

There are two categories of UV filters:

Chemical (organic) filters — Absorb UV radiation and convert it to heat. Examples: avobenzone, homosalate, octisalate, newer generation filters like Tinosorb S/M, Uvinul A Plus, mexoryl SX/XL.
Mineral (inorganic) filters — Primarily scatter and reflect UV. Zinc oxide and titanium dioxide. Better tolerated by sensitive/reactive skin. Zinc oxide provides the broadest single-filter UVA protection.

Modern European and Asian sunscreens typically offer superior UVA protection compared to US-market products, due to access to newer-generation filters (Tinosorb S, Tinosorb M, Uvinul A Plus) not yet approved by the FDA.

The single most important variable is application amount and reapplication frequency, not SPF number. Most people apply 25–50% of the tested amount, dramatically reducing actual protection.

Best Use Cases

Photoageing prevention (the primary driver of visible skin ageing)
Skin cancer risk reduction
Hyperpigmentation prevention and management
Protecting the results of active ingredients (retinoids, vitamin C, AHAs)
Every day, regardless of weather or indoor status

Who May Benefit Most

Everyone. There is no skin type, tone, age, or gender that does not benefit from sun protection. People using active ingredients (retinoids, AHAs, BHAs) have increased UV sensitivity and need sun protection even more.

Cautions

Sunscreen is extremely safe. Rare contact allergies can occur to specific chemical filters (most commonly avobenzone or oxybenzone). Mineral sunscreens (zinc oxide, titanium dioxide) have the lowest allergy risk. The white cast of mineral sunscreens can be cosmetically challenging on darker skin tones — tinted or micronised formulations help. Concerns about systemic absorption of chemical filters have been noted in FDA studies but at levels without established clinical significance.

Common Mistakes

Applying too little — the standard test uses 2mg/cm², which is approximately ¼ teaspoon for the face. Most people apply half this
Not reapplying — sunscreen degrades with UV exposure, sweat, and friction. Reapply every 2 hours during outdoor exposure
Skipping sunscreen on cloudy days (up to 80% of UV penetrates clouds)
Skipping sunscreen indoors near windows (UVA penetrates glass)
Relying on SPF in moisturisers or foundations (insufficient amount applied)
Choosing SPF 100 over SPF 50 thinking it is dramatically better (SPF 50 blocks ~98% UVB, SPF 100 blocks ~99%)
Thinking darker skin tones do not need sunscreen (lower skin cancer risk does not mean zero risk, and photoageing/pigmentation still occur)

Combines Well With

Vitamin C underneath (synergistic photoprotection — vitamin C neutralises free radicals that UV generates)
Niacinamide underneath (calming, oil control)
Every active ingredient (sunscreen protects their work)

May Combine Poorly With

Nothing — sunscreen is universally compatible. Apply as the LAST step of skincare, before makeup

Realistic Timeline

Protection is immediate upon application. Photoageing prevention is cumulative — consistent daily use for years produces dramatically less ageing than inconsistent use. One Australian twin study found that the twin who used sunscreen regularly appeared up to 10 years younger.

Disclaimer

Sunscreen reduces but does not eliminate UV exposure. Seek shade during peak UV hours (10am–4pm). Wear protective clothing when possible. No sunscreen provides 100% protection. Examine unusual moles or skin changes with a dermatologist.