Ive used up to around 600 + (dont exactly remember)
I spaced it out throughout the day though due to the short effect it has in the blood. I think i remember reading a study that showed its peaking for about 3 hours or so, then dropping off.
It worked pretty well for me, And makes your body feel really good. I remember i got a massage, took all 600mg an hour before, and i think it was better than sex lol.