Hair Loss Diagnostics & Blood Tests

Thinning hair has more than one cause, and some of those causes, like iron, thyroid or other hormonal problems, need a different response from standard hair loss treatment. This section covers the diagnostic side: which tests are worth asking for, what the results can and can't tell you, and when testing is worth doing before you start treatment.

Start with what's actually causing your hair loss, which walks through the hormonal and nutritional picture, then which blood tests to get before treating hair loss for the specific markers. If your shedding came on suddenly, our telogen effluvium guide covers that pattern, and the Norwood and Ludwig scales help you describe gradual thinning to a doctor.

Test results need interpreting alongside your history, so treat these guides as preparation for a conversation with a clinician. Our methodology explains how we source and review this content.