welche nährstoffe fehlen bei haarausfall — what symptoms are typical?

The question about nutrient deficiencies in hair loss is complex and not directly addressed in the provided context. Generally, deficiencies in iron, zinc, biotin, vitamin D, and certain B vitamins (e.g., B12, folate) are linked to hair thinning and loss. Typical symptoms include increased shedding, diffuse hair loss, brittle or dull hair, and prolonged shedding phases. However, hair loss has many causes: genetic predisposition (e.g., androgenetic alopecia), hormonal changes, thyroid disorders, autoimmune conditions (alopecia areata), or stress. Nutrient deficiency is only one possible factor. The evidence for individual nutrients is often mechanistic or based on observational studies, not large randomized trials. A blood test by a physician can reliably detect deficiencies. Consumer DNA tests do not provide a direct diagnosis. For persistent hair loss, medical evaluation is recommended.