As of 2015, there is insufficient evidence to rate the effectiveness of saw palmetto as a hair loss treatment, though some men claim that it helps them grow more hair, reports MedlinePlus. The limited available research indicates that saw palmetto shows promise as a treatment for hair loss, notes Healthline.
Saw palmetto extract may help to block 5-alpha-reductase, which converts testosterone to dihydrotestosterone, or DHT, according to Healthline. DHT is responsible for prostate enlargement and hair loss. Because saw palmetto is proven to reduce prostate size, researchers postulate that it may also stop hair loss and encourage hair growth. In a small study of 10 balding men, 60 percent of the participants noted improved hair after using saw palmetto.