Medically reviewed on Jun 7, 2018
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.
Isolated from Huperzia serrata
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.
What is it used for?
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.
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.
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.
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.