Since the production of vitamin D requires exposure to UVB radiation, the use of sunscreens would be expected to inhibit vitamin D synthesis.
Sunscreen acts as a filter, absorbing or reflecting the sun’s ultraviolet rays. The higher the sun protection factor (SPF) of a product, the more effective it is at preventing sunburn (mainly caused by UVB radiation).
Sunscreen can reduce your risk of skin cancer by preventing this radiation from reaching your skin cells and mutating your DNA. Sunscreen has also been shown to reduce skin aging caused by UV rays.
However, sunscreens are not 100% effective. This is mainly because most people don’t use it as directed. Typically, people only apply about a quarter to a third of the amount of sunscreen they need, and most people don’t reapply as directed. This means that some UVB can still reach the surface of your skin.
sunscreen and vitamin D
Many studies have investigated the effects of sunscreen use on vitamin D levels.
Overall, research shows that sunscreen allows for sufficient vitamin D production even with regular use.
In a study conducted by our research team, we conducted a week-long experiment with 40 vacationers on the Spanish island of Tenerife. Participants were instructed on how to properly apply SPF 15 sunscreen to protect their skin.
Not only did the sunscreen protect participants from sunburn, but it also increased their vitamin D levels. This showed that even when using sunscreen, enough UVB radiation reaches the skin to produce vitamin D.
These findings are consistent with two reviews that also looked at actual sunscreen use and vitamin D levels.
Most of the studies included in these reviews either reported that sunscreen use had no effect on vitamin D levels or that sunscreen use led to increased vitamin D levels. This is especially true for field studies, which are likely to best reflect actual sunscreen use and sun exposure.
However, these reviews also found some experimental studies (with more controlled conditions) showing that sunscreen use can interfere with vitamin D synthesis.
However, these studies use UV sources that are not representative of solar UV radiation, which may limit their relevance to real-world conclusions.
Another limitation of the studies evaluated in these reviews is that most studies used low SPF sunscreens (approximately SPF 15 or less). Public health recommendations recommend the use of sunscreens with at least SPF 30, which may have a greater inhibitory effect on vitamin D production.
And most of these studies included only white participants. White skin has less melanin, which acts as a natural sunscreen and protects against UV damage (including sunburn).
