Clinical ResearchResearch compound

Huperzine‑A

Reversible AChE inhibitor, isolated from the Chinese moss Huperzia serrata.

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WHAT IS HUPERZINE-A?

Detailed overview

Huperzine-A is an alkaloid isolated from the moss Huperzia serrata. It is a potent, reversible and selective acetylcholinesterase (AChE) inhibitor – **more selective than Donepezil** – gating prolongs acetylcholine signaling in the synaptic cleft. Clinically improves cognitive function in Alzheimer`s disease (meta-analysis PMID 33851462; rodent meta PMID 36499562). Provides neuroprotection via Wnt signaling, amyloid-β accumulation, and synaptic pathway modulation (PMID 34770940). Anecdotally induces **vivid / lucid dreaming** (the most common community-reported side effect). **Long half-life (~10-14h) makes cycling mandatory** – 2-4 weeks on / 2-4 weeks off, otherwise sustained AChE suppression causes cholinergic overload. Used as a drug in China for Alzheimer`s disease; sold as a dietary supplement in the West.

Mechanism

Reversible AChE inhibitor

Half-life

~10-14 h

Legal status

China Rx / Western OTC supplement

Safety

Side effects, stop signs, contraindications

Side effects · 6

  • Vivid, often lucid dreams and disturbed sleep (the most commonly reported effect)
  • Nausea, stomach upset, diarrhea (cholinergic excess)
  • Increased salivation and sweating
  • Muscle twitching, cramps, fasciculation
  • Dizziness, slow heart rate (bradycardia)
  • Headache, fatigue, irritability with prolonged use

Contraindications · 6

  • Do not combine with other AChE inhibitors (donepezil, rivastigmine, galantamine): additive cholinergic toxicity
  • Caution with bradycardia or cardiac conduction disorders (vagotonic effect)
  • Asthma, COPD: cholinergic tone can trigger bronchospasm
  • Epilepsy / seizure susceptibility: may lower seizure threshold
  • Avoid with peptic ulcer or gastrointestinal obstruction
  • Not advised in pregnancy or breastfeeding; cycling required due to long half-life (2-4 weeks on / off)

Related Nootropics

Same therapeutic category

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MolekulaX Editorial Team·Source-verified · PubMed · FDA · EMA
Updated: June 19, 2026

The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.