Almost nobody applies enough sunscreen, and nearly everyone reapplies too late. This is the one product where using it wrong is close to not using it at all — and it is also the single most effective anti-ageing step available to anyone, at any budget.
The amount
The SPF number on the bottle is measured at roughly two milligrams per square centimetre of skin. For a face and neck that is about a third of a teaspoon, or two fingers’ length of product squeezed onto your index and middle fingers.
Most people apply a quarter to a half of that. Protection does not fall proportionally — it falls faster. Half the amount of an SPF 50 does not give you SPF 25; it gives you considerably less. That is why people who “always wear sunscreen” still accumulate pigment.
The timing
- Last step of the morning routine, after moisturiser, before makeup.
- Every two hours outdoors. Indoors, away from windows, the morning application is usually enough.
- Immediately after swimming or heavy sweating, regardless of what the bottle claims about water resistance.
- Every day of the year, including cloudy days. UVA passes through cloud and through window glass, and UVA is what drives pigment and ageing.
Mineral or chemical
Both protect. They differ in how they feel and who they suit.
- Mineral (zinc oxide, titanium dioxide) sits on the surface, works immediately, rarely stings. Better for reactive skin, rosacea and anyone who gets heat-triggered flushing. Can leave a white cast on deeper skin tones.
- Chemical absorbs light and converts it. Cosmetically lighter, no cast, better for daily wear under makeup. More likely to sting around the eyes.
Look for “broad spectrum” on the label. An SPF number alone describes protection against burning — not against the wavelengths responsible for pigment and ageing.
The places everyone misses
Ears, the sides of the neck, the back of the neck, the chest, the hands, and the strip of scalp along a parting. Eyelids too — a sunscreen that does not sting the eye area exists and is worth finding, because that skin thins first and shows it.
One more: the left side of the face, if you drive. Window glass blocks UVB but lets UVA through, and after years of commuting the difference between the two sides of a face is often visible without any equipment at all.
SPF in makeup does not count
A foundation with SPF 30 is tested at the same two milligrams per square centimetre as any sunscreen. Nobody wears foundation that thickly. Treat SPF in makeup as a small bonus on top of real sunscreen, never as the sunscreen itself.