Your Complete Guide to Sunscreen: Why SPF is Non-Negotiable
SPF is the single most effective anti-ageing product you can own. Learn how sunscreen works, how much to apply, and why you need it even on cloudy days and indoors.
What Does SPF Actually Mean?
SPF (Sun Protection Factor) measures how well a sunscreen protects against UVB rays — the ones that cause sunburn. SPF 30 blocks about 97% of UVB rays; SPF 50 blocks about 98%. Higher is better, but no sunscreen blocks 100%.
UVA vs UVB
UVB rays cause sunburn; UVA rays penetrate deeper, causing premature ageing and increasing skin cancer risk. Look for "broad spectrum" sunscreen — it protects against both types.
How Much Sunscreen to Use
Most people apply far too little. For your face alone, you need about a teaspoon (or two finger-lengths). For your entire body, you need roughly a shot glass worth.
Do I Need Sunscreen Indoors?
Yes — UVA rays penetrate windows. If you sit near a window at home or work, you are still being exposed to skin-ageing UVA radiation. Daily SPF application is recommended regardless of your plans.
Chemical vs Mineral Sunscreen
Chemical sunscreens absorb UV rays and convert them to heat. Mineral sunscreens (containing zinc oxide or titanium dioxide) sit on top of skin and reflect UV rays. Both are effective — choice depends on skin sensitivity and personal preference.
The best sunscreen is the one you'll actually use every day. Find a texture you enjoy and stick with it.
