There's a big chance that you're gonna have a million guys view this topic without anyone bothering to answer your question. But I will give you my own experience with Saw Palmetto. I'm as healthy as I can be, I work out, don't drink and smoke and eat well, no medical conditions whatsoever. Anyhow, I decided to take Saw Palmetto because I needed some kind of internal DHT blocker in my regime.
I started with 320 mg, and within the next few days I was getting the same side effects I got from Rogaine. My face was puffy and droopy, with mild bags under my eyes. But the worst is that all day I felt absolutely fatigued, and I couldn't breathe properly. My heart felt faint to the point I was afraid that if I exercised that day I would pass out, and just under my abdominals, I had constant spaz movement of my insides.
I stopped using it for a few days and decided to go for half the dose, same deal. After that I just quit taking it. I can't say for sure that the same thing will happen to you because our bodies react differently to supplements, but SP was completely toxic to my body and I will never touch it again.
Hope this helps.