• The magnitude and time course of UV radiation-induced photoprotection was investigated in fair-skinned volunteers. Resistance to sunburn was evident three days following single exposures to UV-B, reached a maximum by seven days, and declined gradually over a period of 30 to 40 days. Both the magnitude and time course of UV radiation-induced photoprotection were dose related. The maximal mean protection factor following an exposure to 2 minimal erythemal doses was 4.2. The present findings, along with earlier studies, suggest that there are pronounced spectral differences with regard to the induction of photoprotective adaptation and that UV-B wavelengths are the most effective.
(Arch Dermatol 1984;120:609-612)
Nonaka S, Kaidbey KH, Kligman AM. Photoprotective AdaptationSome Quantitative Aspects. Arch Dermatol. 1984;120(5):609-612. doi:10.1001/archderm.1984.01650410051015