Lay opinion vs evidence: Haarausfall Labor

Lay opinion often holds that a simple lab test or DNA analysis can pinpoint the exact cause of hair loss. The reality is more nuanced. Certain blood tests – such as ferritin (iron stores), vitamin D, zinc, thyroid function (TSH, fT3, fT4), and sex hormones (e.g., DHT) – can provide useful clues for diffuse hair loss, with moderate to strong evidence for iron deficiency and thyroid disorders. However, direct-to-consumer genetic tests for hair loss (e.g., variants in the androgen receptor gene AR or SRD5A2) are a different story. The evidence is weak: effect sizes are small, replication is inconsistent, and individual predictive value is low. Hair loss is multifactorial – genetics, hormones, nutrition, stress, medications, and aging all play a role, and no single test can capture that complexity. In short, some lab tests are evidence-based and clinically valuable, but most genetic 'hair loss tests' overstate their utility. A thorough medical evaluation remains essential.