I used it for a month then found out I had developed hyperprolactinemia, though I was 99.9% sure there was a link especially after what I read when I googled for "saw palmetto hyperprolactinemia" I can't be 100% sure as no doctor I saw had any knowledge on it.
If you are concerned about hair growth and DHT etc and you're on HRT already then read up about progesterones (not progestins they're not known to be as effective).. they are know to be even more effective than finasteride or dutasteride with blocking DHT.