Alzheimer's DementiaElderlyHuperzine A

Huperzine A treatment of Alzheimer’s disease

Most drugs used to treat Alzheimer’s disease are classified as cholinesterase inhibitors.


Researchers in California and Washington DC studied huperzine A, a natural cholinesterase inhibitor derived from the Chinese herb Huperzia serrata.


First, the details.

  • 210 people with mild to moderate Alzheimer’s disease were randomly assigned to a treatment group for at least 16 weeks.
    • Placebo
    • Huperzine A 200 mcg taken twice daily
    • Huperzine A 400 mcg taken twice daily
  • The cognitive effects of huperzine A 200 mcg at week 16 were compared to placebo.
  • Also, the effects of huperzine A 400 mcg were evaluated using a battery of tests.


And, the results.

  • Huperzine A 200 mcg twice daily showed no effect.
  • Huperzine A 400 mcg twice daily showed significant improvement in ADAS-Cog at 11 and 16 weeks vs a decline with placebo group.
    • ADAS-cog is the most popular cognitive test used in research.
  • Changes in clinical global impression of change using the Neuropsychiatric Inventory (NPI) and activities of daily living were not significant at either dose.
    • NPI is a tool to assess psychopathology in patients with dementia and other neuro-psychiatric disorders.


The bottom line?

In this “dose-ranging study,” the primary endpoint of the research was any response to huperzine A 200 mcg. Based on this the authors concluded, “The primary efficacy analysis did not show cognitive benefit with huperzine A 200 mcg twice daily.”


Any future research is likely to focus on the 400 mcg twice daily dose.


A review from 2008 by researchers at the Mayo Clinic, in Rochester, Minnesota, listed several characteristics of huperzine A that suggest it might be beneficial in these patients.

  • A potent, reversible, and selective inhibitor of acetylcholine esterase
  • Rapid absorption and penetration into the brain in animal studies.
  • Compared to the current cholinesterase inhibitors, huperzine A has a longer duration of action.
  • Some studies suggest better tolerability due to fewer peripheral cholinergic side effects.
  • Animal data and clinical safety tests to date have not identified any unexpected toxicity.
  • Gastrointestinal complaints have been reported.


4/19/11 18:59 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.