Huperzia

Huperzia is a type of moss that grows in China. It is related to club mosses (the Lycopodiaceae family) and is known to some botanists as Lycopodium serratum. The whole prepared moss was used traditionally. Modern herbal preparations use only the isolated alkaloid known as huperzine A.

Huperzia moss tea has been used for centuries in traditional Chinese herbalism for fever, as a diuretic, for blood loss, and for irregular menstruation.¹

Huperzine A is an alkaloid found in huperzia that has been reported to prevent the breakdown of acetylcholine, an important substance needed by the nervous system to transmit information from cell to cell.² Animal research has suggested that huperzine A’s ability to preserve acetylcholine may be greater than that of some prescription drugs.^{3, 4} Loss of acetylcholine function is a primary feature of several disorders of brain function, including Alzheimer’s disease. Huperzine A may also have a protective effect on brain tissue, further increasing its theoretical potential for helping reduce symptoms of some brain disorders.^{5, 6}

In a double-blind trial, people with Alzheimer’s disease had significant improvement in memory and cognitive and behavioral functions after taking 200 mcg of huperzine A twice per day for eight weeks.⁷ Another double-blind trial using injected huperzine A confirmed a positive effect in people with dementia, including, but not limited to, Alzheimer’s disease.⁸ Another double-blind trial found that huperzine A (100–150 mcg two to three times per day for four to six weeks) was more effective for improving minor memory loss associated with age-related cognitive decline than the drug piracetam.⁹

Huperzine A has also been shown to enhance memory in adolescent middle school students. A small controlled trial found that 100 mcg of huperizine A two times per day for four weeks was effective in improving memory and learning performance.¹⁰ Although no side effects were reported in this short trial, long-term safety studies are needed before huperizine A is recommended for adolescents or younger children to improve memory and learning performance.

Human research on huperzine A has used 100–200 mcg taken two to three times per day.¹¹

Medications that prevent acetylcholine breakdown often produce side effects, including nausea, vomiting, excess saliva and tear production, and sweating. However, while dizziness was reported in a few people in one study, no severe side effects have been reported in human trials using huperzine A. Further studies are needed to determine the long-term safety of huperzine A.