The net is difficult with Huperzine A. Where you will find more on it will be the various discussion forums --esp the life extension places.

there are contraindications for this herb/drug:
http://www.webmd.com/vitamins-supple...=HUPERZINE%20A

I didn't find yesterday, that it did anything for my thinking. But it sure helped my arthritis pain, muscle weakness etc. It didn't cause any side effects at 50mcg in the morning, except to make me a bit hot and itchy for a few minutes. It also helped my left eye blur which comes with fatigue on the computer.

I am interested mostly in the NMDA actions of it. This pain receptor impacts all of us here. Alzheimer's is a big topic now and quite popular. So it is not a surprise that most articles discuss that.

My son cautioned about not taking it after 2pm...says it will keep you from falling asleep. So I am only using 50mcg in the morning for now. With my GI easy upsets, I cannot afford MORE GI actions, so am very conservative on the dosing. Also I take a beta blocker for blood pressure, and this slows my heart a bit. So caution is necessary for me.

There are other things that block the NMDA receptor... Dextromethorphan, magnesium, Namenda (RX drug), ketamine which some people here use or have used for PN pain.

After a time I'll report back if there is any tolerance issue.
Huperzine A has been around a long time...I recall some posts on our old ADHD forum about it in the past.