Erik Lawrence Kreider - Comment

Federal Register / Vol. 76, No. 117 / Friday, June 17, 2011 page 35625 "Therefore, expressing SPF values as percentages may be confusing. It would imply that the stated percentage of the entire UV spectrum is absorbed by a sunscreen. However, the SPF values only reflect protection against the portion of the UV spectrum that causes sunburn. Additionally, the percentages of UV radiation screened that the submission notes are theoretical. The percentages are determined in a laboratory setting and not under actual use conditions. For example, laboratory tests may show that an SPF 15 sunscreen absorbs 93 percent of UV rays, but, under actual use conditions, the level of protection provided by an SPF 15 sunscreen product may be significantly below 93 percent." No, the percentages are not theoretical, the SPF value implies a percentage of UV absorbance across the relevant erythemal spectrum - % protection = 100-((1/SPF)(100)); SPF = 100/(% exposure) It continues: "There are a number of factors that lead to this decreased protection, the most important being underapplication of the sunscreen product (72 FR 49070 at 49092). Therefore, if SPF values were expressed as percentages, consumers might mistakenly believe that the sunscreen products they are using provide more protection than they really do provide under actual use conditions." This argument is also flawed - if a consumer underapplies a sunscreen product, the effective SPF delivered is also significantly compromised. It is amazing the above would get published by FDA as such. Sunscreens filter UV to a degree. SPF is misleading because it implies the product prevents sunburn for a finite time period, when in reality it only filters a % of incident UV and reduces UV damage over time, it does not eliminate it. SPF 30 (97%) does not provide double the protection of SPF 15 (93%). Using a percentage would better indicate the marginal UV protection levels offered by variously effective products.