Does Sunscreen Cause Vitamin D Deficiency? A 2025 Trial Adds Nuance to the Myth
The 'sunscreen blocks vitamin D' claim is half-wrong and half-right, and a 2025 randomized trial shows exactly where the truth sits.
The open-label randomized Sun-D Trial (British Journal of Dermatology, Nov 18, 2025) found daily high-SPF use lowered blood vitamin D by about 5.2 nmol/L versus discretionary use, with deficiency in 45.7% of the sunscreen group vs 36.9% of controls, leading authors to suggest regular users may need supplementation, not less sunscreen.
The study's authors emphasize that the practical takeaway is supplementing vitamin D when needed, rather than skipping sunscreen and accepting UV damage to gain a small amount of vitamin D.
Questions we get a lot
How much does daily sunscreen lower vitamin D?
In the 2025 Sun-D Trial, daily high-SPF use lowered blood vitamin D by about 5.2 nmol/L versus discretionary use. Deficiency was present in 45.7% of the sunscreen group versus 36.9% of controls. That is a measurable but modest difference.
Should I stop wearing sunscreen to boost vitamin D?
No. The trial's authors recommend supplementation, not less sun protection, for regular sunscreen users. Skipping sunscreen exposes you to UV damage and skin cancer risk for only a small vitamin D gain. A supplement is the safer fix.
r/SkincareAddiction: 'So is the sunscreen-and-vitamin-D thing a myth or not? This 2025 study seems to say both.'