Now huperzine has been gathering interest by American researchers and is currently being evaluated for its benefit in AD patients and to treat epilepsy. So far the early results show that it is no more effective for AD patients than the conventional drugs. Its effect on memory and concentration are very mild and not consistent.
The herb also has a number of disturbing side effects like shortness of breath, chest pain, chest tightness, wheezing, skin hives, itchy skin, diarrhea, vomiting, acidity and inability to sleep. The early reports indicate that most patients tolerate these side effects.
At the moment huperzine is not been recommended by psychiatrists to treat AD because long term results on its safety are not available. Further, its effectiveness is also in doubt because numerous isolated reports indicate that the herb does very little for memory or concentration.
Current recommendation by the Alzheimer’s Association is to keep away from huperzine. Before anyone decides to take huperzine, it is best to consult with your physician. The cost of huperzine is variable and so is the dosage. A month's supply of this herb costs anywhere from $35-$65 but neither the quality or quantity of the active product is guaranteed. Like most herbal supplements, the quality or quantity of the product is never guaranteed.
http://www.mayoclinic.com/health/alzheimers-disease/AN01710