welche vitamine fehlen bei haarausfall — when to see a doctor?

Hair loss can stem from various causes, including nutrient deficiencies. Commonly implicated are iron, zinc, vitamin D, vitamin B12, and biotin. The evidence is mixed: while confirmed deficiency (e.g., iron deficiency anemia) can impair hair growth, supplementation without deficiency rarely helps. Studies show an association between low vitamin D and alopecia, but causal proof is lacking. Biotin deficiency is rare, occurring mainly in specific risk groups. You should see a doctor if hair loss is sudden, patchy, accompanied by itching, scaling, or systemic symptoms like fatigue, pallor, or weight loss. Also seek medical evaluation if the scalp appears inflamed or if hair loss is severe and persistent. A blood panel including ferritin, vitamin D, B12, zinc, and thyroid function can be useful. Genetic tests for single SNPs (e.g., MTHFR) have no clinical relevance for hair health. MyBody‑X tests provide hints but do not replace a medical diagnosis. Supplementation without confirmed deficiency is not recommended and may cause side effects (e.g., vitamin A toxicity).