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18 Jun 2026 · Lumen Derma

SPF Is Still the Cheapest Anti-Ageing We Know

No serum outruns the sun. A practical guide to choosing and actually using sunscreen in Indian humidity — and why dermatologists keep repeating it.

Sunscreen and skincare essentials

Ask any dermatologist for the single most cost-effective anti-ageing intervention and you will hear the same answer: daily broad-spectrum sunscreen. Not because it is glamorous, but because up to 80% of visible facial ageing is driven by ultraviolet exposure.

What "broad spectrum" actually means

UVB burns; UVA ages quietly through windows and cloud. In India, look for:

  • SPF 30 minimum — SPF 50 for pigmentation-prone skin
  • a PA+++ or PA++++ rating (this is the UVA measure)
  • gel or fluid textures that survive 70% humidity

The two-finger rule

Most people apply a quarter of the tested dose. Squeeze two finger-lengths onto your hand for face and neck. Yes, it feels like a lot. No, a pea-sized dab does not count.

Reapplication without wrecking makeup

  1. Morning: full dose on clean skin, wait two minutes, then makeup
  2. Midday: a mineral SPF stick pressed over makeup, or a setting-spray SPF
  3. Outdoor days: shade breaks matter more than perfection

If one product decision could change your skin trajectory in five years, this is it. Everything else in our clinic builds on this foundation.