Abstract
Since UV radiation is a known carcinogen, we should replace sun protection factor (SPF) testing on human subjects with in vitro spectroscopic measurements on artificial substrates. In vitro measurements would permit use of more accurate UV radiation spectra to measure absorbance spectra that are more representative of actual human exposure to sunlight. Sunscreen films are not uniform and many products are not photostable. Step film models, based on ingredients, are commonly used to predict SPF, but do not account adequately for lack of photostability or novel vehicles. Spectroscopic measurements using a dynamic model and substrates with films simulating sunscreens on human skin may replace SPF testing on human subjects.
Financial & competing interests disclosure
Joseph Stanfield is the owner and president of Suncare Research Laboratories, LLC, a research-oriented testing laboratory specializing in evaluations of suncare products for manufacturers. Clients include numerous companies in the USA, Europe, the UK and Asia. He is also a consultant for Neutrogena Corporation, Mary Kay, Inc. and Galderma Laboratories. He has submitted a provisional US patent application entitled: ‘In vitro Measurement of Sunscreen Protection’. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.