Doctor, I’ve stopped using sunscreen. My neighbour said it blocks vitamin D, and my blood test already shows I’m deficient.”
This is one of the most common misconceptions I encounter in my clinic. Patients who have diligently used sunscreen for years suddenly abandon it after hearing that it might be responsible for low vitamin D levels. Some stop using it altogether, despite struggling with melasma, acne marks, or sun sensitivity.After 15 years in dermatology, I’ve learned that myths often survive because they contain a grain of scientific truth. The idea that sunscreen causes vitamin D deficiency sounds perfectly logical—until you examine the evidence.
Vitamin D is indeed produced when ultraviolet B (UVB) rays from sunlight interact with the skin. Sunscreens are designed to reduce UVB penetration. Therefore, many people conclude that sunscreen must prevent vitamin D production.The science tells a far more nuanced story.In laboratory settings, when sunscreen is applied exactly as recommended—at a thickness of 2 mg/cm² over every exposed area—it can significantly reduce UVB exposure. But real life bears little resemblance to laboratory conditions.Most people apply far less than the recommended amount, often only a quarter to half of what is required. They miss areas such as the ears, eyelids, neck and hands. Many forget to reapply every two hours, and inevitably lose protection through sweating, rubbing, or washing. Even those who use sunscreen daily receive incidental sun exposure while walking outdoors, driving, exercising, or simply moving between buildings.As a result, enough ultraviolet radiation usually reaches the skin to permit vitamin D synthesis.This is precisely why numerous clinical studies have failed to demonstrate that regular sunscreen use leads to clinically significant vitamin D deficiency in everyday life.If sunscreen were truly the primary culprit, populations that use it consistently should have widespread deficiency. That isn’t what research has found.UV rays cause visible damage
