The Sun-D Trial: Does Daily SPF 50+ Really Raise Your Vitamin D Risk?
The first large randomized trial to test the sunscreen-vitamin D claim is in, and the real-world answer is more nuanced than the headlines.
In the open-label randomized controlled Sun-D Trial (628 participants in eastern Australia), vitamin D deficiency at study end was higher in the daily-sunscreen group (45.7%) than the discretionary-use control group (36.9%), a prevalence ratio of 1.33 (95% CI 1.14-1.55).
The trial investigators frame the result as a reason for regular sunscreen users to consider vitamin D from diet or supplements, not as a reason to reduce sun protection.
Questions we get a lot
Did the Sun-D Trial prove sunscreen causes vitamin D deficiency?
It found higher deficiency in daily-sunscreen users (45.7%) than discretionary users (36.9%), a prevalence ratio of 1.33. That shows an association in a randomized setting, but the effect is modest and easily offset. The authors point to supplementation rather than abandoning sunscreen.
If I wear sunscreen daily, should I take a vitamin D supplement?
The trial's findings suggest regular sunscreen users are a reasonable group to consider vitamin D from diet or supplements. Talk to your clinician about testing and an appropriate dose. The goal is keeping vitamin D adequate while still protecting your skin from UV damage.
r/SkincareAddiction: 'I wear SPF 50 every single day. Does the Sun-D Trial mean I'm probably vitamin D deficient?'