"serving size" is usually 200mg. I take 100mg if I need it during the day and up to 300mg when it's dark. I've never taken more than 500mg in 24 hours.
I think it's probably not a good idea to use if you are bipolar, because it can temporarily imbalance things. I am bipolar. But, when I know I'm at a rough low because of whatever, I'll take some. I have mood swings at times but they aren't as severe as last year and years before. I'm not married any more and I'm on better meds, so the swings aren't anywhere nearl as bad. I think the former helped that more than the latter. It can help those patches. It's a common misconception that 5-htp causes drowsiness. It causes a small release of seratonin, one of the happy brain chemicals. It let's loose more of it than chocolate but it acts longer, whereas chocolate is a quick on and gone thing. It also seems to help with relaxing the large muscles in the body, probably because I'm not as tense from the depression. That helps with yoga, because I'm usually kind of wired to be going to yoga class! Wired to go relax. Being on two mood stabilizers probably causes it to not be as short-acting with me, because they cause all sorts of things I shouldn't do to last much longer, so I mostly quit doing those things.