Huperzine A

What is Huperzine A?

Club mosses are primitive, vascular plants that differ from true mosses by having specialized fluid-conducting tissues, but like mosses, they reproduce by means of spores, which are either clustered into small cones or borne in the axils of the small scale-like leaves. Plants older than 15 years may only grow to 10 cm in height. Some species of Lycopodium are called ground pine or creeping cedar, especially those that resemble miniature hemlocks with flattened fan-shaped branches that are often used for Christmas decorations.

Scientific Name(s)

Isolated from Huperzia serrata

Common Name(s)

Huperzine A is isolated from the club mossHuperzia serrata. It is also known as Chien Tseng Ta, Jin Bu Buan, Qian Ceng Ta, She Zu Cao, Shi Song. Other products containing huperzine A include Memorzine, Brainmax, Neuroflow.

Trade Names

What is it used for?

Traditional/Ethnobotanical uses

The use of club moss can be traced back to the Chinese pharmacopoeias of the Tang dynasty as Shi Song, used for the treatment of rheumatism and colds, to relax muscles and tendons, and to improve blood circulation. The club moss H. serrata has been used in Chinese folk medicine under the name Qian Ceng Ta (Chien Tseng Ta) for the treatment of bruises, strains, swelling, and, more recently, organophosphate poisoning, myasthenia gravis, and schizophrenia. The study of the chemistry and pharmacology of the plant and its alkaloids gained momentum in the 1980s from Chinese scientists.

Alzheimer disease

A Cochrane review of the effect of huperzine A in Alzheimer disease, as well as other reviews, note the lack of quality long-term clinical trials to support definitive statements about a place in therapy for huperzine A, despite numerous clinical studies being undertaken.

Other uses

Historically, club moss has been used for the treatment of bruises, strains, swelling, rheumatism, and colds, to relax muscles and tendons, and to improve blood circulation. Because of its anticholinesterase activity, huperzine A, a constituent of the whole plant, has been studied for potential use in treating Alzheimer disease and other CNS disorders; however, there is still insufficient evidence to support its routine use.

What is the recommended dosage?

Huperzine A has been studied at oral dosages of 0.2 to 0.4 mg/day for Alzheimer disease.


Contraindications have not yet been identified.


Information regarding safety and efficacy in pregnancy and lactation is lacking.


None well documented.

Side Effects

In clinical trials, cholinergic adverse reactions have been noted, including hyperactivity, nasal obstruction, nausea, vomiting, diarrhea, insomnia, anxiety, dizziness, thirst, and constipation. One trial reported abnormalities in electrocardiogram patterns (cardiac ischemia and arrhythmia).


Symptoms of acute toxicity are similar to those of other cholinergic inhibitors and include muscular tremor, drooling, tears, increased bronchial secretions, and incontinence. No mutagenicity or teratogenicity were found in rodent studies.

References. Huperzine A. Review of Natural Products. Facts & Comparisons [database online]. St. Louis, MO: Wolters Kluwer Health Inc; July 2010.


Huperzine A is a substance extracted from a plant called Chinese club moss (Huperzia serrata). Sold as a dietary supplement, huperzine A is typically touted as a treatment for Alzheimer's disease.

Used in alternative medicine, huperzine A has been found to act as a cholinesterase inhibitor, a type of medicine used to prevent the breakdown of acetylcholine (a chemical essential to learning and memory)

Not only used as a treatment for Alzheimer's disease, huperzine A is also said to enhance learning and memory and to protect against age-related cognitive decline.

In addition, huperzine A is sometimes used to boost energy, increase alertness, fight depression, and aid in the treatment of myasthenia gravis, an autoimmune disorder that affects the muscles. However, the research is limited.

Memory Enhancement

Very few studies have tested the use of huperzine A for memory enhancement. However, an older, small study published in the Chinese journal Acta Pharmacologica Sinica in 1999 found that huperzine A helped improve memory and learning in a group of adolescent students.

For the study, 68 junior high students (all of whom complained of memory inadequacy) were given either huperzine A or a placebo every day for four weeks. By the study's end, members of the huperzine A group showed greater improvements in learning and memory (compared to members of the placebo group).

More research is needed before huperzine A can be recommended for memory enhancement.