Can Vitamin D 25-OH help with Haut?

Whether vitamin D (25-OH) can help with skin is a nuanced question. Vitamin D is synthesized in the skin via sunlight and plays roles in cell growth, immune modulation, and inflammation. Deficiency is linked to skin conditions like psoriasis, acne, and atopic dermatitis. However, evidence for a general skin benefit from supplementation in people with normal levels is weak. In cases of confirmed deficiency, correcting levels may improve skin barrier function and reduce inflammation. Most evidence is mechanistic or observational; large randomized controlled trials specifically for skin health are lacking. Also, 25-hydroxyvitamin D is the storage form, not the active hormone. Direct skin benefits from oral intake are not guaranteed. A blood test is advisable before supplementing, as excess can be harmful. In summary: vitamin D can support skin health when deficient, but it is not a miracle cure. Evidence is moderate and context-dependent.