Huperzine A is a chemical compound that can be isolated from the plant Huperzia serrata (Chinese club moss), a traditional Chinese remedy used for contusions, strains, swelling, and schizophrenia. It can also be made in a laboratory. Huperzine A is commonly listed as “Huperzia serrata extract,” “HupA,” or “Chinese club moss” on dietary supplement product labels. It is often marketed for brain health and cognitive performance, with claims of enhanced brain power, memory, alertness, attention, concentration, and focus.

No reliable scientific evidence supports the use of huperzine A to enhance cognitive performance. Multi-ingredient products containing huperzine A could be unsafe.

Is it an approved dietary supplement ingredient?

Although it is marketed in the U.S. as a dietary supplement ingredient, huperzine A is an approved drug in some other countries. For example, huperzine A is available in most hospitals in China and is used to “treat” Alzheimer’s disease. In the U.S., however, it is unclear whether huperzine A can be legally marketed as a dietary supplement.

Is huperzine A effective as a dietary supplement?

To date, no studies have shown huperzine A to enhance cognitive performance in otherwise healthy individuals. Preliminary evidence suggests huperzine might have beneficial effects on cognitive function among Alzheimer’s disease patients, but more research is needed to establish this conclusively. Some companies have been marketing “supplements” containing huperzine A with illegal claims that their products can “treat” Alzheimer’s.

Is huperzine A safe as a dietary supplement?

Currently, the Alzheimer’s Association recommends not taking huperzine A, especially with prescription drugs, because the combination could increase the risk of serious side effects. Taking huperzine A in combination with other dietary supplement ingredients (especially ones marketed as nootropics) might pose additional health risks.

Commonly reported adverse effects include:

  • Decreased heart rate
  • Nausea
  • Vomiting
  • Diarrhea
  • Dizziness
  • Sweating
  • Blurred vision
  • Insomnia

Overall, safety data is lacking and long-term use is not well understood. In addition, multi-ingredient products containing huperzine A have been shown to contain varying amounts of huperzine A inconsistent with the Supplement Facts label, as well as ingredients not allowed in dietary supplements.

Can Military Service Members use huperzine A?

Huperzine A is not prohibited for use by DoD members, and it will not cause a positive result on a routine military drug test. However, given the limited evidence of its safety, we advise caution with products that contain this ingredient.

In addition, some dietary supplement products containing huperzine A include substances prohibited for use. Consuming such ingredients could put your health, career, or both at risk. In some cases, these ingredients might not be listed on a product’s label, so you could consume prohibited ingredients unknowingly. Using products that have been third-party certified can help you avoid this possibility.


Updated 18 January 2024


Bauer, B. A. (2019). Huperzine A: Can it treat Alzheimer’s?   Retrieved 3 October 2019 from

Bridwell, R. E., Yoo, M. J., Grove, J. J., & Ng, P. C. (2020). Chest pain from supplement use in an active duty soldier: A case report. Military Medicine, 185(9-10), e1857–e1859. doi:10.1093/milmed/usaa043

Crawford, C., Wang, Y.-H., Avula, B., Bae, J.-Y., Khan, I. A., & Deuster, P. A. (2020). The scoop on brain health dietary supplement products containing huperzine A. Clinical Toxicology, Article 1713337. doi:10.1080/15563650.2020.1713337

Hao, Z., Liu, M., Liu, Z., & Lu, D. (2009). Huperzine A for vascular dementia. Cochrane Database of Systematic Reviews, 2009(2), Article CD007365. doi:10.1002/14651858.CD007365.pub2

Huang, P., Li, B., Guo, Y.-H., Feng, S., Hu, J., & Liu, Q.-Q. (2019). Efficacy and safety of huperzine A in treating patients with mild cognitive impairment: A systematic review and meta-analysis (in Chinese). China Journal Of Chinese Materia Medica, 44(3), 582–588. doi:10.19540/j.cnki.cjcmm.20180925.008

Jędrejko, K., Catlin, O., Stewart, T., Anderson, A., Muszyńska, B., & Catlin, D. H. (2023). Unauthorized ingredients in “nootropic” dietary supplements: A review of the history, pharmacology, prevalence, international regulations, and potential as doping agents. Drug Testing and Analysis, 15(8), 803–839. doi:10.1002/dta.3529

Li, J., Wu, H. M., Zhou, R. L., Liu, G. J., Dong, B. R., & Wu, H. M. (2008). Huperzine A for Alzheimer's disease. Cochrane Database of Systematic Reviews, 2008(2), Article CD005592. doi:10.1002/14651858.CD005592.pub2

Morasch, K. C., Aaron, C. L., Moon, J. E., & Gordon, R. K. (2015). Physiological and neurobehavioral effects of cholinesterase inhibition in healthy adults. Physiology & Behavior, 138, 165–172. doi:10.1016/j.physbeh.2014.09.010

Rafii, M. S., Walsh, S., Little, J. T., Behan, K., Reynolds, B., Ward, C., . . . Aisen, P. S. (2011). A phase II trial of huperzine A in mild to moderate Alzheimer disease. Neurology, 76(16), 1389–1394. doi:10.1212/WNL.0b013e318216eb7b

Tucker, J., Fischer, T., Upjohn, L., Mazzera, D., & Kumar, M. (2018). Unapproved pharmaceutical ingredients included in dietary supplements associated with U.S. Food and Drug Administration warnings. JAMA Network Open, 1(6), Article e183337. doi:10.1001/jamanetworkopen.2018.3337

U. S. Food & Drug Administration. (2019). FDA takes action against 17 companies for illegally selling products claiming to treat Alzheimer’s disease.   Retrieved 21 November 2019 from

U.S. Food & Drug Administration. (2023). CFSAN adverse event reporting system (CAERS).  from

Wessinger, C. M., Inman, C. L., Weinstock, J., & Weiss, E. P. (2021). Effect of huperzine A on cognitive function and perception of effort during exercise: A randomized double-blind crossover trial. International Journal of Exercise Science, 14(2), 727–741.

Yang, G., Wang, Y., Tian, J., & Liu, J.-P. (2013). Huperzine A for Alzheimer’s disease: A systematic review and meta-analysis of randomized clinical trials. PLoS ONE, 8(9), Article e74916. doi:10.1371/journal.pone.0074916

Yue, J., Dong, B. R., Lin, X., Yang, M., Wu, H. M., & Wu, T. (2012). Huperzine A for mild cognitive impairment. Cochrane Database of Systematic Reviews, 2012(12), Article CD008827. doi:10.1002/14651858.CD008827.pub2