Sun care
Why reapplying sunscreen matters more than the SPF number
By Dr. Arjun Kapoor (MD, Fellowship in Cosmetic Dermatology) · 2 Jul 2026 · 5 min read
Most people choose sunscreen based on the SPF number alone, then apply it once in the morning and forget about it. That single habit — not the SPF number — is the biggest reason sunscreen 'doesn't work' for pigmentation and tanning.
SPF protection fades, it doesn't hold
Sunscreen filters degrade with UV exposure, sweat and friction from clothing or touching your face. In Indian conditions — high UV index, heat and humidity — a morning application is typically down to a fraction of its labelled protection by early afternoon.
The two-finger rule
Most people apply far less sunscreen than the amount used in SPF testing. For the face and neck, use roughly two finger-lengths of product, applied generously rather than dabbed on thinly.
When to reapply
Reapply every 3 hours if you're indoors near windows or outdoors intermittently, and every 2 hours with direct, continuous sun exposure. A setting spray or a stick sunscreen makes reapplying over makeup realistic.
The bottom line
A well-applied, properly reapplied SPF 30 outperforms a thinly-applied, never-reapplied SPF 50. If you only change one skincare habit this year, make it reapplication.
This article is for general information and does not replace a dermatologist's assessment of your specific skin or hair. For a personalised read, try our free AI skin analysis or book a consultation.