Herbs & Botanicals
Huperzia (qian ceng ta)
What is huperzia? What is it used for?
Huperzia is a type of moss that grows only in China. Huperzia moss tea has been used for centuries in traditional Chinese medicine to treat fever, blood loss and irregular menstruation. Traditionally, the whole moss was used in herbal formulas, but modern preparations use only huperzine-A, an alkaloid found in huperzia that prevents the breakdown of acetylcholine.
Since loss of acetylcholine function is a characteristic of several disorders of brain function, huperzine-A is believed to be effective in stopping the spread of Alzheimer's disease. Huperzine-A may also protect brain tissue, further increasing its potential for helping reduce symptoms of some brain disorders. There is also evidence that suggests huperzine is effective in increasing memory.
How much huperzia should I take?
There is no current recommended daily allowance for huperzia. However, most human studies with huperzine-A have used 100 – 200 mcg taken two to three times per day.
What forms of huperzia are available?
Fresh or dried huperzia moss can still be found at some Asian specialty markets. Huperzine-A is available at health food stores in tablet or capsule form.
What can happen if I take too much huperzia? Are there any interactions I should be aware of? What precautions should I take?
Substances that prevent acetylcholine from breaking down often produce side-effects such as nausea, vomiting, excess saliva production, and sweating. However, aside from occasional cases of dizziness, no severe side-effects have been reported in human trials using huperzine A. Further studies are needed to determine its long-term safety.
Huperzine-A may react negatively with donepezil (a medication often taken by Alzheimer's patients to reduce memory loss) and tacrine (an acetylcholinesterase inhibitor which is also taken by Alzheimer's patients). Make sure to consult with a qualified health care provider before taking huperzia, huperzine-A or any other dietary supplement or herbal medicine.
- Cheng DH, Tang XC. Comparative studies of huperzine A, E2020, and tacrine on behavior and cholinesterase activities. Pharmacol Biochem Behav 1998;60:377 – 86.
- Kozikowski AP, Tückmantel W. Chemistry, Pharmacology, and Clinical Efficacy of the Chinese Nootropic Agent Huperzine A. www.huperzine.net/invent.htm, 26 June 2000.
- Skolnick AA. Old Chinese herbal medicine used for fever yields possible new Alzheimer's disease therapy [news item]. JAMA 1997;277:776.
- Ved HS, Koenig ML, Dave JR, et al. Huperzine A, a potential therapeutic agent for dementia, reduces neuronal cell death caused by glutamate. Neuroreport 1997;8:963 – 8.
- Wang Z, Ren G, Zhao Y, et al. A double-blind study of huperzine A and piracetam in patients with age-associated memory impairment and dementia. In: Kanba S, Richelson E (eds). Herbal Medicines for Nonpsychiatric Diseases. Tokyo: Seiwa Shoten Publishers, 1999, 39 – 50.