Researchers shed light on discrepancies between lab tests and reality
Scientists in the UK and Switzerland say consumers should rethink how they interpret the sun protection factor (SPF) printed on sunscreen bottles.
Retailers have long used SPF to indicate how long sunscreen protected skin can endure sunlight without burning. Concerns that topical sunscreens do not provide the protection they claim are not new and arise from discrepancies between simulated and natural sunlight. Lab tests also assume consumers apply an even layer of sunscreen (2mg per cm2of exposed skin). In reality, this is in the region of 0.5–1.5mg cm–3, is far from uniform, and there are other factors, such as perspiration and rubbing, to consider.
Interested? The full story can be read in Chemistry World.
The original article can be read below and is free to access until 4th October 2017
Labelled sunscreen SPFs may overestimate protection in natural sunlight
Brian Diffey* and Uli Osterwalder
Photochem. Photobiol. Sci., 2017, Advance Article