SPF 30 sunscreen (left) SPF 30 Moisturiser (right). Image by: Institute of Ageing and Chronic Disease at the University of Liverpool
Moisturizers containing sunscreen provide less protection, and are less uniformly applied by users, than sunscreen alone with the same SPF, according to new findings.
Presented at the British Association of Dermatologists Annual Meeting in Edinburgh, U.K. (3rd-5th July 2018), the research was conducted by investigators from the Department of Eye and Vision Science at the University of Liverpool, U.K.
The study team, led by Kevin Hamill, PhD and Dr. Austin McCormick, used an ultraviolet (UV) light camera to assess how effectively people apply sunscreen and moisturizer with sun protection to their face. On the UV photographs, successfully covered areas of the face appear dark as the sun protection material is absorbing the UV energy; the darker the image, the more effective the sun protection.
Dr. Hamill is a lecturer in the Department of Eye and Vision Science, and Dr. McCormick is a consultant opthalmic and oculoplastic surgeon at The University Hospital Aintree, a teaching hospital in Liverpool, U.K.
In the study, 60 participants—14 men and 46 women, aged 18-57 years—were asked to apply sun protection at two visits. At the first visit they applied SPF 30 sunscreen, and at the second a moisturizer with SPF 30 protection.
Analysis of the UV photographs showed that when applying the moisturizer product, the participants missed 16% of their faces, compared to 11% missed with the dedicated sunscreen product. In particular, with the moisturizer 21% of the eyelid area—a common site for skin cancers—was missed, compared to 14% of the eyelid area missed with the dedicated sunscreen.
Study findings also suggested that individuals do not apply a sun-protective moisturizer as thickly as they do sunscreen, so do not receive the full benefits of the product's SPF. The photographs of the participants using the moisturizer were noticeably less dark on average than the photographs of the same individual using dedicated sunscreen, indicating that less UV light was being absorbed.
"One of the things I particularly enjoyed about this research is that its very visual and fairly easy for people to understand," said Dr. McCormick, in a press release. "The darker the image, the more sun protection people are getting."
"We expected the moisturizer to perform worse than the sunscreen on overall protection, as it seemed intuitive that people apply moisturizer quite thinly on the whole. While we were correct in this, the research did throw up some unexpected surprises. We thought that people would miss more of their face with the sunscreen, as we've all had that stinging sensation when you accidentally rub some in your eye and we expected that this would lead people to be conservative and avoid the eyes. Actually, people missed more of their face when using the moisturizer."
On average, the men were significantly better at applying the two products than women, according to the findings. Other groups that proved better at sun protection application were people with darker skin tones and older participants.
Participants were asked to rate their perceived ability to apply the products both before and after viewing the UV images. For sunscreen, perceived ability dropped from 90% positive to 42%, and for moisturiser from 85% to 38%, which the investigators say indicates that participants were not aware of their failure to achieve adequate coverage.
"Although moisturizer with SPF does provide sun protection, our research suggests that it's not on the same level as sunscreen," said Dr. McCormick. "We would not recommend it as a like-for-like replacement for your sun protection needs."