Sunscreen's two-hour reapplication rule lacks scientific evidence, analysis finds

The common guideline to reapply sunscreen every two hours while in the sun is not based on strong scientific evidence. This recommendation appears to have originated from a 2007 proposed rule by the FDA, which cited studies and public health statements. However, an examination of the cited evidence, including a 2001 study by Wright et al., reveals a shaky foundation with small sample sizes and questionable methodology. The FDA's 2011 final rule maintained the two-hour guideline, asserting that data supported it, but the underlying research remains weak. AI

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RANK_REASON Article critically examines the origins and evidence base for a widely accepted public health guideline.

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• Wright et al.
• AAD
• EPA
• Rigel et al.

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