Several studies have been done over the past few years with huperzine A both in China and the United States. These studies have shown that Huperzine A is many times more effective and selective than tacrine (a cholinesterase-inhibiting pharmaceutical drug) in inhibiting cholinesterase (Cheng 1996). Huperzine A has also been found to be beneficial in patients with Alzheimer's disease. Scientists at Zhejiang Medical University, in Hangzhou, China administered 0.2 mg of huperzine A to fifty patients with Alzheimer's disease for a period of eight weeks and compared the results to a group who received placebo pills (Xu 1995). The study was done in a double blind, placebo controlled and randomized manner. The results showed 58 percent of the patients treated with huperzine A had improvements in memory, cognition, and behavioral functions whereas only 36 percent of those on placebo improved. No severe side effects were found. Blood pressure, heart rate, electrocardiogram, electroencephalogram, liver and urine tests did not show any major abnormalities. The researchers say, "Huperzine A is a promising drug for symptomatic treatment of Alzheimer's disease."

This club moss extract may also benefit older individuals with dementia. A study was conducted with fifty-six patients suffering from multi-infarct dementia (multiple small strokes) and one hundred patients with senile memory disorders (Zhang 1991). The dose used for multi-infarct dementia was 0.05 mg twice a day for four weeks, whereas that for senile memory disorders was 0.03 mg twice a day for two weeks. Most patients had an improvement in memory. A few reported slight dizziness, but this did not affect the therapeutic effects. Huperzine was even mentioned in the Journal of the American Medical Association as a possible herbal therapy for Alzheimer's disease (Skolnick 1997).

Availability
Huperzine A is sold either by itself in dosages of 0.05 mg, or in lower dosages combined with other mind-boosting nutrients.

My Personal Experience
I took a capsule containing 50 micrograms (0.05 mg) of huperzine A in the morning at 9 AM on an empty stomach. Within an hour I could feel a subtle effect. This consisted mostly of feeling slightly more alert and focused. Over the next hour I took two additional capsules and then ate breakfast. My focus and concentration were slightly improved all day long and well into the evening. It didn't seem that huperzine A had any effect on mood, libido, or appetite. No side effects occurred. One study has shown that huperzine A is absorbed rapidly when taken orally, distributed widely in the body, and eliminated at a moderate rate (Qian 1995). This rapid absorption and moderate elimination is consistent with my observation of the effects within an hour and the continuation of the effects late into the evening.

Recommendations
Huperzine A appears to be a promising alternative to cholinesterase inhibitor drugs used in Alzheimer's disease. More studies are required to determine its long-term safety and side effect profile. Until we learn more about this herbal extract, I would recommend its use be limited to the therapy of AD, and preferably under medical supervision.