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SPF 100+ Sunscreen Is More Protective Against Sunburn Than SPF 50+
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The authors compared sunburn protection between SPF 100+ and SPF 50+ sunscreens. A total of 199 participants wore both sunscreens simultaneously on the face during 6.1 ± 1.3 hours of sun exposure, and erythema was assessed the following day. As assessed by a blinded investigator, 55.3% (110/199) of the participants appeared more sunburned on the SPF 50+ side compared with 5% (10/199) on the SPF 100+ side. In self-assessment, 40.7% (81/199) of the participants reported increased erythema scores of ≥1 on the SPF 50+ side compared with 13.6% (27/199) on the SPF 100+ side.
The results indicate that SPF 100+ sunscreen is more effective in protecting against sunburn than SPF 50+ sunscreen in a single day of sun exposure.
– InYoung Kim, MD, PhD
- Written by
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In recent years, a debate has played out both in the medical literature and the press about the marginal utility afforded by higher-SPF sunscreens. A quick Google search will produce a litany of commentaries decrying sunscreens with high-labeled SPFs as "unnecessary." This view is based on SPF 30 sunscreens blocking 97% of UVB rays, with higher-SPF products offering marginally increased 98% to 99% protection due to a logarithmic scale. However, the critical fact that this view fails to take into account is that labeled SPFs are based on a standardized, strictly regulated application/reapplication protocol, which is not representative of how most consumers actually apply sunscreen. Multiple studies have demonstrated that most consumers apply less than half the 2 mg/cm2 density of sunscreen utilized for standardized SPF testing—suggesting that the proportion of UVB blocked by a given sunscreen product in the laboratory setting may be a gross overestimate of the protection afforded in real-world settings.
In this study, a group of 199 skiers/snowboarders in Vail, Colorado, were randomized to apply SPF 50 sunscreen to one side of their face and SPF 100 to the other. No instructions were given as to the density of application or the timing of reapplication so that a real-world usage was achieved. Erythema was clinically accessed the following day by a blinded investigator. On average, partiicpants applied sunscreen to a density of approximately half that mandated for SPF testing in the laboratory setting and most did not reapply. When assessed, 55.3% of participants exhibited more sunburn on the SPF 50 side as opposed to only 5% on the SPF 100 side.
These important results remind us that findings obtained in a controlled laboratory environment may inaccurately translate to real life. Those who question the added benefits of high-SPF sunscreens due to minimal added protection from UVB fail to consider that the actual protection in real-life settings is typically substantially lower than those resulting from laboratory tests. The results of this study demonstrate that higher SPF sunscreens provide meaningful added sunburn protection in real-world situations, suggesting that the proposed FDA SPF cap of 50+ would not be beneficial or appropriate.
Abstract
BACKGROUND
The value of additional photoprotection provided by use of high SPF sunscreens is controversial and limited clinical evidence exists.
OBJECTIVE
To compare the sunburn protection provided by SPF100+ and SPF50+ sunscreen in conditions of actual use.
METHODS
199 healthy men and women (≥18 years) participated in a natural sunlight, single exposure, split face, randomized, double blind study in Vail, Colorado. Each participant wore both sunscreens simultaneously during activities with no usage restrictions other than treatment area designation. Erythema was clinically assessed the day following exposure. Comparative efficacy was evaluated through bilateral comparison of sunburn between treatment areas and erythema score as evaluated separately for each treatment area.
RESULTS
Following an average 6.1 ± 1.3 hours of sun exposure, investigator blinded evaluation identified 55.3% (110/199) of the participants as more sunburned on the SPF50+ and 5% (10/199) on the SPF100+ protected side. Post exposure, 40.7% (81/199) of the participants exhibited increased erythema scores ≥ 1 on the SPF50+ protected side as compared to 13.6% (27/199) on the SPF100+.
LIMITATIONS
Single day exposure may not extrapolate to benefits of longer-term protection.
CONCLUSION
SPF100+ sunscreen was significantly more effective in protecting against sunburn than SPF50+ sunscreen in actual-use conditions.
Additional Info
SPF 100+ Sunscreen Is More Protective Against Sunburn Than SPF 50+ in Actual-Use: Results of a Randomized, Double-Blind, Split-Face, Natural Sunlight Exposure, Clinical Trial
J Am Acad Dermatol 2017 Dec 29;[EPub Ahead of Print], JD Williams, P Maitra, E Atillasoy, MM Wu, AS Farberg, DS Rigelposted by dermatica at
February 06, 2018
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