Hup-A, selagine, Qian Ceng Ta extract · Evidence-based safety and harm-reduction overview.
| Also known as | Hup-A, selagine, Qian Ceng Ta extract |
| Category | Nootropic |
| source | Huperzia serrata, Chinese club moss |
| active_dose_range | 50-200 micrograms daily (very small amounts) |
| mechanism_class | Reversible acetylcholinesterase inhibitor |
| half_life | Relatively long (approximately 12 hours or longer) |
| year_isolated | 1980s |
| US legal status | Huperzine-A is sold in the United States as a dietary supplement ingredient, often within memory or cognition formulas. It is not FDA-approved as a drug to treat any disease. In some countries it has been studied or used in a medicinal context. |
Huperzine-A is a naturally occurring alkaloid originally isolated from the Chinese club moss Huperzia serrata. It acts as a reversible acetylcholinesterase inhibitor, meaning it can slow the breakdown of the neurotransmitter acetylcholine. This mechanism is similar to some pharmaceutical Alzheimer disease medications, though huperzine-A is less potent.
Huperzine-A works as a reversible inhibitor of acetylcholinesterase, the enzyme that breaks down acetylcholine. By slowing this enzyme, it increases acetylcholine availability at neuronal synapses. This cholinergic enhancement is thought to support cognitive function, though excessive acetylcholine can produce side effects. The mechanism is well understood, but functional significance in healthy humans is unclear.
Huperzine-A was first isolated from the Chinese club moss Huperzia serrata in the 1980s by Chinese researchers. It has been studied extensively in China and some other countries for cognitive impairment and dementia. The compound became available as a dietary supplement in the US and is also used in some countries as a pharmaceutical.
Research suggests huperzine-A inhibits acetylcholinesterase, and some studies, many conducted in China, report cognitive effects in people with dementia or memory complaints. The evidence is mixed, several trials are of limited methodological quality, and data in healthy adults are sparse. Recent independent research outside China is limited.
In clinical studies, huperzine-A has typically been administered at oral doses ranging from 50 to 200 micrograms (mcg) daily, often divided across two doses. This is notably smaller than most other nootropic compounds. Trial durations have ranged from weeks to several months.
This is general research/context information, not medical advice or a recommended protocol.
Huperzine-A is sometimes included in multi-ingredient cognitive formulas but should not be combined with other acetylcholinesterase inhibitors or cholinergic compounds without medical oversight, as overdose risk is significant. Informational only.
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Compare testing optionsIt is sold as a dietary supplement ingredient in the US and is not FDA-approved as a drug to treat any condition.
We do not provide dosing guidance. Because it is potent at very small amounts and has cholinergic effects, any use should be reviewed with a clinician.
It blocks the breakdown of acetylcholine, so excess cholinergic activity can produce effects such as nausea, sweating, slowed heart rate, and cramping.
It works by the same mechanism as some Alzheimer drugs (acetylcholinesterase inhibition), but it is less potent, less selective, and is sold as a supplement rather than a pharmaceutical.
Yes. It has a relatively long half-life, so accumulation may occur with repeated dosing, and chronic use effects are not well studied in humans.
Medical & legal disclaimer. This site is for informational and harm-reduction purposes only. It is not medical advice and is not a substitute for a licensed healthcare professional. The compounds discussed are largely not approved by the FDA for human use and many are sold strictly as research chemicals 'not for human consumption.' Nothing here is an endorsement to purchase, possess, or use any substance. Laws vary by jurisdiction. Always consult a qualified physician and follow the law where you live.
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