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Huperzine A

Huperzine A is a compound extracted from a Chinese club moss that slows the breakdown of acetylcholine, a brain chemical involved in memory and learning. People mostly look at it for Alzheimer's disease, where the evidence is moderate: a meta-analysis found thinking-test scores improved at 8, 12, and 16 weeks, and memory scores improved too. The studies only lasted a few months, and evidence for daily activities and vascular dementia is limited.

Best evidence
Grade B
Conditions studied
2
Outcomes
6
Graded outcomes
0321

Evidence by condition

  • Strong
  • Moderate
  • Limited
  • Very limited

2 conditions

Alzheimer’s Disease: outcomes studied for Huperzine A
GradeOutcomeEffectSizeStudiesPeopleStudies list
Cognitive Function (MMSE)

Significant improvement in MMSE scores at 8, 12, and 16 weeks (meta-analysis)

Improves (the measure goes up)Moderate effect1,823 people
Cognitive Function (ADAS-Cog)

2.27-point improvement at 400 mcg BID (Phase II trial)

Improves (the measure goes up)Moderate effect210 people
Memory (WMS)

Significant improvement in Wechsler Memory Scale at 8 and 12 weeks

Improves (the measure goes up)Moderate effect600 people
Activities of Daily Living

Improved ADL scores at 6, 12, and 16 weeks

Improves (the measure goes up)Moderate effect400 people
Cognitive Function (200 mcg BID)

Lower dose (200 mcg BID) showed no demonstrable effect in Phase II trial

Improves (the measure goes up)Small effect210 people

Vascular Dementia

Vascular Dementia: outcomes studied for Huperzine A
GradeOutcomeEffectSizeStudiesPeopleStudies list
Cognitive Function

Cognitive benefits in vascular dementia (meta-analysis)

Improves (the measure goes up)Moderate effect300 people

Key findings

  • Cognitive Function (MMSE)Alzheimer’s DiseaseImproves (the measure goes up)
  • Cognitive Function (ADAS-Cog)Alzheimer’s DiseaseImproves (the measure goes up)
  • Memory (WMS)Alzheimer’s DiseaseImproves (the measure goes up)

Studies cited

2 studies from PubMed

  1. Huperzine A, a nootropic alkaloid, inhibits N-methyl-D-aspartate-induced current in rat dissociated hippocampal neuronsNeuroscience, 2001 · PMID 11516831
  2. The NMDA receptor ion channel: a site for binding of Huperzine AJ Appl Toxicol, 2001 · PMID 11920920