How much product is enough
In short
Two pumps of cleanser, three drops of serum, a pea of cream. Sunscreen is the one almost everyone under-applies: it takes two full finger-lengths.
The sunscreen gap
Sun protection factors are measured at 2 milligrams of sunscreen per square centimetre of skin. When researchers measured what people actually put on, it was a quarter to a half of that, with protection falling well below the number on the bottle.
The unit dermatologists use
The fingertip unit is the amount of cream squeezed from a standard tube along the last joint of an index finger, about half a gram. One unit covers two palm-sized areas; the face and neck take about two and a half. It was designed for prescription creams and remains the most practical yardstick for everyday products.
Why more is not better
A cleanser spreads as a thin film, lifts oil and dirt into it and rinses away. Adding more means more surfactant on the skin for longer, and surfactant contact, not dirt, is what causes dryness and tightness after washing. A cream's lipid film slows evaporation; a thicker film does not slow it further, it just sits on the surface and feels heavy. Serum drops that will not spread mean the skin was too dry, not the dose too small.
The routine
- 1 Two pumps of cleanser on damp skin.
- 2 Three drops of serum, pressed over slightly damp skin.
- 3 A pea of cream, warmed between the fingertips.
- 4 In the morning, two finger-lengths of sunscreen. It feels like a lot. That is the point.
Figures are study averages; individual skin varies.
Sources (4)
- Long CC, Finlay AY. The finger-tip unit: a new practical measure. Clinical and Experimental Dermatology, 1991. Measurement study in healthy volunteers.
- Ananthapadmanabhan KP et al. Cleansing without compromise: the impact of cleansers on the skin barrier and the technology of mild cleansing. Dermatologic Therapy, 2004. Review.
- Azurdia RM et al. Sunscreen application by photosensitive patients is inadequate for protection. British Journal of Dermatology, 1999. Observational study of applied sunscreen thickness.
- Taylor S, Diffey B. Simple dosage guide for suncreams will help users. BMJ, 2002. Dosage guide.
