Can sunscreens with more than 50 SPF truly provide sun protection? In a new study, the effectiveness of SPF 50 and SPF 100 sunscreens were tested and compared under normal conditions.
The usual assumption is that a higher sun protection factor or SPF rating can provide more sun protection. Researchers from the New York School of Medicine and Icahn School of Medicine tested the effectiveness of sunscreens with a variety of SPF levels. Unlike other studies which are normally done in a laboratory setting, these tests considered other factors by testing in a real-world environment [R].
In this randomized, double-blind study, 199 healthy male and female individuals participated in Colorado, United States. They were provided with two bottles of sunscreen, one for each side of their face (left and right). The participants did not know which bottle had the SPF 50 sunscreen and which one had the SPF 100 [R].
SPF 100 sunscreens provided more UV rays protection than SPF 50 [R].
After a day’s worth of sun exposure, the erythema scores of all participants were examined by certified clinicians. Erythema or skin redness is a result of sun damage. The results showed that 40.7% or 81 out of 199 individuals had elevated erythema scores on the SPF 50 side, while 13.6% or 27 out of 199 individuals had elevated erythema scores on the SPF 100 side [R].
Although this provided ample amount of data on sunscreen use in a real-world setting, some limitations were noted in that only a single day of sun exposure was examined. The study was not able to venture further into what the effects of long-term use of both sunscreens would be [R].
New FDA Guidelines on Sunscreen
Recent research studies show that a significant amount of sunscreen ingredients is absorbed into the blood through the skin. This is why the FDA has mandated further testing of sunscreen ingredients [R].
The FDA states that titanium oxide and zinc oxide are two safe and beneficial ingredients. On the other hand, trolamine salicylate and aminobenzoic acid (PABA) are deemed to be unsafe and ineffective for sunscreen use. According to the FDA, the following 12 ingredients have yet to be tested further for safety: avobenzone, oxybenzone, sulisobenzone, padimate O, octisalate, octocrylene, octinoxate, meradimate, ensulizole, homosalate, dioxybenzone, and cinoxate [R].
Given this safety information, the FDA still recommends the use of sunscreen for its acknowledged health benefits. According to the FDA, while they are proceeding with this regulation effort, people are advised to use broad-spectrum sunscreen with an SPF of 15 or higher along with other sun protection measures.