Genetic Testing for Hair Loss: What the Tests Actually Tell You

Consumer genetic tests promise to reveal your hair loss risk — your destiny in a tube. The science behind them is real but modest. The consumer applications run ahead of what they can actually deliver. Here's what's worth testing and what's marketing.

01What genetics actually determines in hair loss

AGA is polygenic — driven by dozens of gene variants, not one gene. The androgen receptor (AR) variant inherited on the X chromosome (maternal grandfather effect) is the most well-characterized, but dozens of other loci contribute. Current consumer tests can identify some of these variants and provide a risk score, but the prediction accuracy for any individual is modest — positive results don't guarantee loss, negative results don't prevent it.

02The one test that genuinely changes treatment decisions

SULT1A1 enzyme activity testing predicts minoxidil response. SULT1A1 is the scalp enzyme that converts minoxidil to its active form. Men and women with low SULT1A1 activity are significantly more likely to be non-responders to topical minoxidil. If you test low, oral minoxidil — which bypasses this enzyme step — is the right choice. This test is actually actionable.

03The mirror test

If you're looking at your temples and crown in the mirror with concern, you already have the most reliable diagnostic tool available. The genetic test for current hair loss isn't a saliva kit — it's your actual hair. The genetic test adds value for prediction in the absence of visible loss, and even then, the accurate prediction is "you'll probably experience some loss" for most people with a family history who are asking the question.