Hello, My son at 8 has been getting shorter - what I mean is that 2 he was at the 90th percentile. At 3 he stopped growing for almost a whole year, at which time he fell to 30th percentile. At this time he also began displaying ASD and ADHD symptoms. Upon receiving medication ( guanfacine ) at 5 he went up a bit to 40th percentile. Everytime he has an increase in medicine, he has a slight increase in height. But as he is getting more mature and learning self-control, the increases are less frequent (up to 2.25 mg/day now). But his height is now at the 25%. I should also like to say that he is not inattentive - he is severely hyperactive impulsive. Glutamine supplements made him super severely hyper withith 30 mins or so of taking them. It seems to me there is a problem in his GABA-glutamine-glutamate cycle so that he has insufficient GABA. Would a GABA supplement help with growth, calming, etc. Would it be safe to try taking before bed so as not to interfere with guanfacine?