Huperzine A is an extract from a club moss (Huperzia serrata) that has been used for centuries in Chinese folk medicine. Huperzine's action has been attributed to its ability to strongly inhibit acetylcholinesterase, the enzyme that breaks down acetylcholine in the synaptic cleft. Acetylcholine is involved in memory and learning. By inhibiting the enzyme that breaks it down, more acetylcholine becomes available to stimulate neurons. Alzheimer's disease is a condition where there's a relative shortage of acetylcholine.

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 200 mcg 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."

Where it is found
Huperzine A is a substance purified from a plant called Chinese club moss.

BY INJECTION:
For prevention of muscle weakness caused by a disease called myasthenia gravis. Healthcare providers give Huperzine A daily as a shot.
Possi ble Side effects / Precautions / Possible Interactions:
Huperzine A seems to be safe when used for a short time, such as less than one month. It can cause some side effects including nausea, diarrhea, vomiting, sweating, blurred vision, slurred speech, restlessness, loss of appetite (anorexia), contraction and twitching of muscle fibers (fasciculations), cramping, increased saliva and urine, inability to control urination (incontinence), high blood pressure, and slowed heart rate (bradycardia).

Special Precautions & Warnings:
Pregnancy and breast-feeding: Not enough is known about the use of huperzine A during pregnancy and breast-feeding. Stay on the safe side and avoid use.

Heart disease: Huperzine A can slow the heart rate. This might be a problem for people who already have a slow heart rate (bradycardia) or other heart conditions related to heart rate. If you have heart disease, use huperzine A cautiously.

Epilepsy: Since huperzine A seems to affect brain chemicals, there is concern that it might make epilepsy worse. If you have a seizure disorder such as epilepsy, use huperzine A cautiously.

Gastrointestinal (GI) tract blockage: There is a concern that using huperzine A might make GI blockage worse. That is because huperzine A can increase mucous and fluid secretions in the intestine, causing “congestion.” This “pro-secretory effect” is due to the way huperzine A affects a body chemical called acetylcholine. If you have a GI tract blockage, check with your healthcare provider before you use huperzine A.

Sores in the stomach or the first part of the small intestine (peptic ulcers): There is a concern that using huperzine A might make peptic ulcers worse. That is because huperzine A can increase mucous and fluid secretions in the stomach and intestine, causing “congestion.” This “pro-secretory effect” is due to the way huperzine A affects a body chemical called acetylcholine. If you have peptic ulcers, check with your healthcare provider before you use huperzine A.

Lung conditions such as asthma or emphysema: There is a concern that using huperzine A might make asthma or emphysema worse. That is because huperzine A can increase mucous and fluid secretions in the lung, causing “congestion.” This “pro-secretory effect” is due to the way huperzine A affects a body chemical called acetylcholine. If you have asthma or emphysema, check with your healthcare provider before you use huperzine A.

Urinary tract or reproductive system blockage: There is a concern that using huperzine A might make blockage of the urinary or reproductive system worse. That is because huperzine A can increase mucous and fluid secretions in these organs, causing “congestion.” This “pro-secretory effect” is due to the way huperzine A affects a body chemical called acetylcholine. If you have a urinary tract or reproductive system blockage, check with your healthcare provider before you use huperzine A.

Research studies / References