Enhancing Sunscreen Efficacy for Realistic Application

By: Elsa Jungman, University of Paris XI, and Howard I. Maibach, MD, University of California

Posted: June 30, 2010, from the July 2010 issue of Cosmetics & Toiletries.

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Furthermore, Galenic formulations should be considered when developing formulations, as ointments lead to better application than alcoholic solutions and sprays.^{8, 9} Because high SPF sunscreens tend to be sticky, dermatologists should instead advise patients to use lower SPF level sunscreens but in greater quantity. There is only a 4% difference in UVB protection between an SPF 15 and an SPF 30 sunscreen. Therefore, using a lower SPF would not only be more aesthetically pleasing for the consumer, it would encourage subjects to apply more sunscreen.¹⁷

Comments
Some experts have recommended changing the amount of sunscreen used for SPF testing in order to adapt to real life usage conditions. While the FDA considered public comments and data/information brought to its attention and proposed a rule to amend the Final Monograph for OTC sunscreens in August 2007,¹⁸ the rule did not include a proposed method change. This was not only because the group believes that lowering the sunscreen density is not necessary to more accurately test for sunburn protection, but also because changing the amount of sunscreen used for SPF testing implies international coordination toward a globalized method and labeling requirements.

Instead, the FDA prefers that product labels encourage consumers to apply a thicker layer. Manufacturers can select one or more of the following terms: liberally, generously, smoothly or evenly. In addition, it would be beneficial for sunscreen labels to direct consumers to: apply to all skin exposed to the sun, serving as a reminder that all uncovered anatomic sites are exposed to UV. No sweat resistance testing was proposed in the new FDA monograph either, which could be important for individuals practicing outdoor exercise.

Finally, the efficacy of day care and makeup products containing UV filters should also be investigated. Foundations are applied in thinner layers and the protection achieved is likely far from the SPF level indicated on the label. A special SPF test should exist for such makeup and moisturizers that incorporate UV filters.

Sunscreen application and use have become highly efficient but educational messages to the consumer require further development. Besides learning to apply the right amount, consumers must also understand that wearing sunscreen does not mean they should spend longer periods of time in the sun. In addition, sunscreen should not be used as the primary prevention but as a complement to shade, clothing and broad-brimmed hats.