Does sunscreen prevent the synthesis of vitamin D?

To stay healthy, we need both vitamin D and good sun protection. And good news: the two are perfectly compatible!

Vitamin D actually includes two compounds: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). According to Anses, vitamin D plays an essential role in the quality of our bone and muscle tissue and also contributes to the proper functioning and strengthening of our immune system. Yet, the majority of French people do not consume enough of it. There are two ways to meet our daily vitamin D needs: exposure to the sun and consuming foods rich in vitamin D.

In this article, we will focus on the first method: sun exposure. When our skin is exposed to the sun, and more precisely to UVB rays, our body manages to produce vitamin D. The problem is that many people mistakenly believe they must expose themselves to the sun without any protection to synthesize vitamin D. But, as you probably already know, the sun’s rays are very dangerous for the skin. It is therefore essential to protect yourself during any sun exposure to avoid burns and other more serious diseases that may result.

Sunscreen and vitamin D are not enemies

So, we may wonder if, when we apply sunscreen to our skin, our body is still capable of synthesizing vitamin D. And the answer is yes!

Indeed, according to the Skin Cancer Foundation, studies have never shown that daily use of sunscreen leads to a vitamin D deficiency. We can therefore use a sunscreen daily while maintaining a sufficient vitamin D level.

Even when applied perfectly, in sufficient quantity, frequently, and with a high SPF, sunscreen will never block 100% of UV rays. For example, an SPF 50 sunscreen will filter about 98% of UVB rays, leaving 2% of UVB reaching your skin. This may explain why your body can still synthesize vitamin D while being very well protected.

10 to 15 minutes of sun exposure (arms, legs, abdomen or back), 2 to 3 times a week, at a UV index above 3, allow you to benefit from a sufficient vitamin D level. If you live in a region where the UV index is low in winter (below 3), you can maintain a proper vitamin D level by spending time outdoors at midday, rolling up your sleeves or pants, and wearing sunscreen, of course. Don’t forget to also wear a wide‑brimmed hat and sunglasses for optimal sun protection.

How can you know if your vitamin D level is sufficient? First of all, consult your doctor, who can prescribe blood tests or, if necessary, vitamin D supplements or ampoules. Some people may be at higher risk of vitamin D deficiency, such as those with naturally dark skin or those taking certain medications.

Certain foods are naturally rich in vitamin D and, combined with protected sun exposure, can help you maintain a sufficiently high level. This includes fatty fish like salmon, mackerel, or tuna, and to a lesser extent egg yolk, beef liver, and cheese.

In general, don’t forget that UV‑protective clothing, if certified UPF 50+, will protect you more effectively from the sun’s harmful effects than sunscreen. Wearing a UV‑t‑shirt will indeed safely and consistently shield your skin from UV rays all day long. In any case, very high‑protection sunscreen (SPF 50) will be useful to complete your sun protection and protect areas of your body not covered by clothing or UV accessories like UV mittens or neck gaiters.

 

• https://www.skincancer.org/blog/sun-protection-and-vitamin-d/
• https://www.anses.fr/fr/content/vitamine-d-pourquoi-et-comment-assurer-un-apport-suffisant