Natural Compound

Huperzine-A

Huperzia serrata-derived huperzine A

Evidence TierCWADA NOT PROHIBITED

tuneTypical Dose

100 MCG to 200 MCG

watchEffect Window

Approximately 4 weeks for core endpoint assessment.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Huperzine-A is an alkaloid from Huperzia serrata that inhibits acetylcholinesterase. It is used for memory and learning support by increasing acetylcholine availability in neural synapses.

Huperzine A has a real acetylcholinesterase-inhibiting mechanism, but the human evidence is more mixed than many nootropic summaries imply. Dementia studies show some cognitive signals, yet the best modern phase II trial missed its primary endpoint at standard dosing. For healthy users, evidence is much thinner than the pharmacology, while adverse effects such as nausea, insomnia, and bradycardia remain credible.

Reversible AChE inhibition with reported NMDA antagonism, increasing cholinergic signaling and supporting memory/learning-related outcomes.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Mixed dementia-trial cognitive signals
  • Pharmacologic acetylcholinesterase inhibition

Secondary Outcomes

  • Study-relevant concentration stability
  • Self-reported recall confidence

Safety

Contraindications and Interactions

Contraindications

  • Bradycardia
  • Asthma
  • Epilepsy
  • Concurrent AChE inhibitor use

Side effects

  • Nausea
  • Dizziness
  • Headache
  • Insomnia
  • Bradycardia

Interactions

  • Other AChE inhibitors
  • Anticholinergic agents
  • Seizure-threshold-altering drugs

Avoid if

  • Unstable cardiac conduction
  • Active severe asthma
  • Active seizure disorder
  • Current AChE inhibitor stack

Evidence

Study-level References

huperzine-a-SRC-001Multicenter randomized placebo-controlled phase II trial
Sourceopen_in_new

Rafii MS, Walsh S, Little JT, Behan K, Reynolds B, Ward C, et al. A phase II trial of huperzine A in mild to moderate Alzheimer disease. Neurology. 2011;76(16):1389-1394. doi:10.1212/WNL.0b013e318216eb7b. PMID:21502597.

Population: Individuals with mild to moderate Alzheimer disease across multiple centers.

Dose protocol: 200 mcg BID or 400 mcg BID for at least 16 weeks in mild to moderate Alzheimer disease

Key findings: Standard-dose huperzine A did not improve the primary ADAS-Cog endpoint versus placebo, although some higher-dose secondary cognitive signals were observed.

Notes: Stronger than older small studies for calibration because it is multicenter and placebo-controlled.

Paper content

The best modern huperzine A trial is mixed rather than clearly positive. Standard-dose treatment did not beat placebo on the primary ADAS-Cog endpoint, although the higher-dose arm showed some secondary cognitive signals. This is enough for cautious interest, not for strong supplement confidence.

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