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Huperzine A and acute cognitive performance: grade C

Limited evidence. Direction: No effect.

C Limited

Educational guidance, not medical advice

Why this grade

Rubric condition met: Two small placebo-controlled single-dose studies in healthy adults, both null on overall cognition, apart from maintained declarative recall at 200 micrograms in one

In healthy young adults given a single 100 or 200 microgram dose (12 per group), huperzine A inhibited blood acetylcholinesterase but did not improve neurobehavioral performance compared with placebo, apart from maintained declarative recall at 200 micrograms; the authors suggest ceiling effects. In a crossover trial of 15 exercise-trained adults, a single 200 microgram dose changed no cognitive test compared with placebo and raised ratings of how hard the exercise felt. Both studies are small, so the evidence supports limited, mixed findings rather than N.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)201520202025RCTCrossover RCTWessinger 2021, 2021: crossover RCT, n = 15, result not recordedMorasch 2015, 2015: RCT, n not recorded, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Morasch 20152015RCTnot recordedresult not recorded
Wessinger 20212021crossover RCT15result not recorded

Effect of Huperzine A on Cognitive Function and Perception of Effort during Exercise: A Randomized Double-Blind Crossover Trial.

Wessinger CM, Inman CL, Weinstock J. Effect of Huperzine A on Cognitive Function and Perception of Effort during Exercise: A Randomized Double-Blind Crossover Trial Int J Exerc Sci, 2021. PMID 34567353

Result not recorded
Design
Double-blind, randomized-sequence crossover trial (single dose)
Sample
n = 15
Population
Exercise-trained healthy adults (11 women, 4 men; mean age 30.4)
Funding
not stated in the PubMed or Crossref record; full text not read

Physiological and neurobehavioral effects of cholinesterase inhibition in healthy adults.

Morasch KC, Aaron CL, Moon JE. Physiological and neurobehavioral effects of cholinesterase inhibition in healthy adults Physiol Behav, 2015. PMID 25455867

Result not recorded
Design
Randomized, placebo-controlled single-dose study (7 arms, n=12 per drug/dose)
Population
Healthy young adults
Funding
US Government support, non-PHS, and non-US Government support (PubMed publication types); funder not named in the abstract; full text not read

Search and history

Search (): huperzine[tiab] AND (exercise[tiab] OR athletes[tiab] OR "young adults"[tiab] OR "healthy adults"[tiab])

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page