What it is and how it works
Huperzine-A is an alkaloid compound derived from the herb Huperzia serrata and is an ingredient of herbal formulas used in Chinese medicine to treat Alzheimer disease and age-related cognitive decline. Animal studies show that huperzine-A reversibly inhibits acetylcholinesterase (the brain enzyme that breaks down the neurotransmitter acetylcholine), slows age-related neurotoxicity, regulates the secretion of nerve growth factor, and protects against oxidative stress and neuronal cell death associated with ?-amyloid formation. All of these mechanisms probably contribute to the beneficial effects of huperzine-A on cognition and memory.
Summary of research evidence
Findings from preclinical animal studies suggest that huperzine-A may have a longer duration of action, better penetration of the blood–brain barrier, and be a more potent and more specific inhibitor of acetylcholinesterase than available prescription cholinesterase inhibitors–the principal treatments of dementia in Western countries. Placebo-controlled human trials report consistent beneficial effects of huperzine-A in age-related memory loss, Alzheimer disease, and vascular dementia at very small doses–between 200 and 400 micrograms per day. A meta-analysis of eight placebo-controlled randomized controlled trials (733 total subjects) on huperzine-A in Alzheimer disease and two placebo-controlled randomized controlled trials on huperzine A in vascular dementia reported improved global mental functioning as measured by changes in mini-mental status exam (MMSE) and improvements in daily activities. The significance of these findings is limited by small study size and poor methodological quality of some studies included in the meta-analysis.
Infrequent adverse effects include transient dizziness, nausea, and diarrhea. To learn more about huperzine-A and other complementary and alternative approaches for treating mild cognitive impairment (MCI) or dementia read my e-book “Dementia and mild cognitive decline: The Integrative Mental Health Solution.”