Can low testosterone cause hair loss?

Not in the way most men think. The classic male-pattern baldness on your scalp is driven by DHT (a potent form of testosterone) and your genetics, not by low testosterone. Men with low testosterone are not protected from going bald.

The distinction that clears up the confusion is between two different kinds of hair:

• Scalp hair — a receding hairline or thinning crown depends on how sensitive your follicles are to DHT, which is inherited; you can have normal or even low testosterone and still lose it, which is also why DHT-blocking medication like finasteride can slow balding
• Body and facial hair — beard density and chest or leg hair do depend on having enough testosterone, so low levels can genuinely thin them

That split is the key to reading your own situation. If your body and facial hair are thinning alongside fatigue, low libido or low mood, that pattern points towards low testosterone and is worth checking against the wider symptoms of low testosterone. If it is only your scalp receding while your beard and body hair are unchanged, that is genetics and DHT rather than a hormone shortfall, and a testosterone test will usually come back normal.

There is a counterintuitive twist worth knowing. Because scalp balding is DHT-driven, raising testosterone, whether naturally or through TRT, can occasionally speed up genetic hair loss rather than reverse it, since more testosterone means more raw material for DHT. So a testosterone boost is not a hair-loss treatment, and expecting it to regrow a hairline gets the biology backwards.

What to do: do not assume a receding hairline means low testosterone, and do not expect a testosterone boost to regrow scalp hair. If you have broader low-T symptoms, get a morning blood test. For scalp hair specifically, that is a separate conversation about DHT and genetics with your doctor.