Is Vitamin D Test useful for Haut?

A vitamin D test for skin health has limited utility. Vitamin D is synthesized in the skin via sunlight and is involved in conditions like psoriasis and wound healing. A blood test measures total 25-hydroxyvitamin D, which fluctuates seasonally and does not directly reflect skin status. In cases of suspected deficiency (e.g., dark skin, low sun exposure, chronic skin disease), testing can guide supplementation. However, it does not replace dermatological evaluation. Evidence for routine testing is weak; most guidelines discourage screening in healthy individuals. Consumer tests may be inaccurate. Conclusion: useful only when deficiency risk is high, not as a general skin assessment.