SPF 100+ sunscreen more effective than SPF 50+ against sunburn
22 Mar 2020
Sunscreens are designed to absorb the radiation in the UVB range. However, this can reduce capacity of skin to produce vitamin D.When it comes to protection against ultraviolet radiation–induced erythema and sunburn, sunscreen with sun protection factor (SPF) 100+ is significantly better than that with SPF 50+ in actual use at the beach, a recent study has shown.
The researchers conducted a prospective, randomized, double-blind, single-centre, split-body/face study of 55 healthy individuals to compare the sunburn protective efficacy of SPF 50+ and SPF 100+ sunscreens under actual use in a beach vacation setting.
Participants applied both sunscreens to randomly assigned sides of the face or body for up to 5 consecutive days. A single grader performed blinded clinical evaluation of erythema, as well as objective instrumental assessments, colorimetry and diffuse reflectance spectroscopy, the next morning after each exposure to the sun.
Of the participants, 31 (56 percent) had more sunburn on the SPF 50+ side compared to four (7 percent) on the SPF 100+ side after 5 days. In addition, mean erythema intensity was statistically significantly less on the SPF 100+ side than on the SPF 50+ side.
Sunburn occurring exclusively on the SPF 50+ was first observed after 1 day of sun exposure, while that on the SPF 100+ side was seen after 3 days of sun exposure.
This study had certain limitations, chief of which was the monitoring of only the initial sunscreen application. In addition, only one individual with skin phototype I was included, and participants were recruited from a local beach area.
“Beach vacations are high-risk settings for overexposure to ultraviolet radiation,” the researchers noted.