I researched it years ago, and decided NO... it's not worth it.
Those sorts of claims and assumptions are usually made from companies pushing to sell their miracle cures to people who for some reason won't just go get a prescription for Propecia or Avodart.
In the reports I read, Saw Palmetto does NOT reduce blood serum DHT, while Propecia and Avodart do. There seems to be some evidence that maybe, possibly, Saw Palmetto helps with prostate problems. A little. MAYBE. But if so, it does it by a different mechanism than the prescription anti-DHT drugs, so with all that, there's NO reason to believe it acts as a general anti-DHT drug that will help with hair loss.
The question ya gotta ask yourself is: is it worth risking permanently losing more hair to find out if Saw Palmetto works?
~Kate~