A recent investigation by CBC Marketplace has revealed discrepancies between the SPF numbers printed on sunscreen bottles and the actual protection provided. This discrepancy can give users a false sense of security when relying on sunscreen for sun protection.
Marketplace conducted tests on a popular SPF 50 sunscreen at five accredited laboratories in Canada and the U.S. The results varied widely, with the labs reporting SPF values of 34, 50, 60, 44, and 15 for the same product. This highlights the lack of oversight in the testing process.
The investigation did not disclose the specific sunscreen product tested, emphasizing the focus on SPF determination rather than any particular brand. Studies have shown that variability in sunscreen testing results is common.
Experts, including Brian Diffey, a photobiology professor, expressed concerns over the inconsistent SPF results. Health Canada, responsible for regulating sunscreen in Canada, did not comment on the testing outcomes.
Sun Protection Factor (SPF) indicates the level of protection against UVB rays, which cause sunburn. However, it does not account for UVA rays’ damaging effects, which can lead to premature aging and skin cancer. The higher the SPF number, the greater the UVB protection, with SPF 50, 30, and 15 blocking approximately 98%, 97%, and 93% of UVB rays, respectively.
The testing process for SPF involves human volunteers exposed to simulated sunlight to determine the sunscreen’s efficacy. While newer testing methods exist, the current approach relies on subjective human assessments. Factors like application technique and skin absorption influence SPF results.
Despite testing limitations and fraud instances in the sunscreen industry, experts emphasize the importance of using sunscreen for skin protection. Consumers are advised to apply sunscreen generously and not solely rely on SPF numbers. Additional measures like seeking shade and avoiding peak sun hours complement sunscreen use for effective sun protection.
