I tried melatonin a few times and experienced some very groggy mornings. I also experienced a few nights where I could not sleep after taking a 3mg tab.
For those considering it, let me suggest a very small dose (0.5-0.75 mg, or 1/4th of a tablet) and 9-10 hours to try it out. Don't pop one of these at 2am and expect to feel great the next day.
I've used melatonin. When I first tried it, I was on a lot of medication, so my brain chemistry was pretty whacked, and it would leave me feeling half asleep for like 3 days. I agree with the suggestion to try a low dose version. However, it also helps to take co-q-10 the following morning. It is the co-enzyme to melatonin and wakes the brain up. It counteracts the effects of melatonin.
For those saying melatonin left you wide awake: It also has immune function uses. I have had times when I took it (during the day) to treat a health issue rather than a sleep issue and the impact was to wake me up.
Are your groggy mornings after only sleeping a few hours? I only use melatonin if I am able to get at least 7 hours of sleep, or maybe 6.5 in a pinch, but with or without melatonin I'll be groggy in the morning with less than 6.5 hours of sleep. I take 1mg doses, although I initially took 3mg and didn't notice a difference. This study seems to show that 3mg is overkill, and that .3mg is probably sufficient:
I had one night of hitting the sack at 10am after taking 3mg and not sleeping at all (maybe 4am?). The other night I took 3mg 8-9 hours before waking up and I still felt groggy.
I wouldn't deter people from melatonin but they should start with very small doses.
Trader Joe's has 500mcg (i.e. 0.5mg) tablets. Walmart had 300mcg tablets, which were absolutely ideal, but they've stopped carrying them locally.
There was an excellent article I read a few years back which made the case that 300mcg is the ideal dose for nightly use. Over 1mg, the body adapts to it and it loses effect.
The smaller tablets are preferable to breaking larger ones, since it's hard to be consistent due to the manner in which they crack, as well as the potentially uneven distribution of melatonin to filler in each tablet.
For those considering it, let me suggest a very small dose (0.5-0.75 mg, or 1/4th of a tablet) and 9-10 hours to try it out. Don't pop one of these at 2am and expect to feel great the next day.