Q. What is “Huperzine A?” I have seen it in formulas with ginkgo.

A. Huperzine A is a substance derived from the moss Huperzia serrata. It has been used in China for centuries. Studies on huperzine A are producing extremely encouraging results in the treatment of Alzheimer’s disease—a well-known degenerative brain disorder that manifests as a progressive deterioration of memory and mental function.

Alzheimer’s disease is believed to be caused by a reduced level of acetylcholine—a key neurotransmitter in the brain that is especially important for memory. Huperzine A enhances memory by preventing the breakdown of acetylcholine as a result of inhibiting the enzyme (acetyl-cholinesterase) responsible for breaking down acetylcholine. As a result, acetylcholine levels increase dramatically within the brain cells and memory improves. Clinical studies conducted in China have shown considerable benefit in the treatment of dementia at a dose of 200 mcg twice daily. However, these results need to be confirmed before the benefits attributed to huperzine can be considered proven.