According to multiple sources, sunscreen does not block vitamin D absorption entirely, but it can reduce it substantially. Studies have shown that people who use sunscreen on a consistent basis can maintain healthy vitamin D levels while still getting adequate sun protection. In fact, a study recorded an increase of vitamin D in participants during a week of cloudless weather, with very high UV index, even when sunscreens were used properly and prevented sunburn. Sunlight contains UVA and UVB radiation, and the latter is essential for vitamin D synthesis. Two sunscreens with the same SPF were compared, and sunscreen with a high UVA protection factor enabled significantly higher vitamin D synthesis than a low UVA protection factor sunscreen, likely because it allows more UVB transmission.
It is important to note that the amount of sunscreen that you wear can also play a role in your body’s ability to absorb vitamin D. The different SPF levels of sunscreen provide different amounts of sun protection, and even SPF50+ formulations let a small percentage of UV through to the skin, which in turn triggers the body’s natural vitamin D synthesis process.
While sunscreen use can prevent skin cancer, there are concerns that it may increase the risk of vitamin D deficiency. However, the weight of evidence from field trials and observational studies suggests that the risk is low. It is also worth noting that some sunscreen ingredients, such as oxybenzone, have been linked to hormone disruption. Mineral sunscreens made with zinc oxide and titanium dioxide tend to rate better than chemical sunscreens in the EWG sunscreen database, but to reduce their response to sunlight, manufacturers use forms of minerals coated with inert chemicals.
In summary, sunscreen can reduce vitamin D absorption, but it does not block it entirely. The benefits of using sunscreen far outweigh any belief that sunscreen blocks vitamin D, and people who use sunscreen on a consistent basis can maintain healthy vitamin D levels while still getting adequate sun protection. It is important to wear sunscreen and follow the instructions on the label to ensure proper sun protection.
