From Nutrient Journal
Huperzine A (Huperzine Alpha, HupA) is a nootropic alkaloid purified from club moss Huperzia serrata, a herb used in Chinese folk medicine. Huperzine A is especially interesting for its cognitive enhancing and neuroprotective properties. Therefore, this alkaloid is also investigated for treatment of Alzheimer’s disease and dementia. As a bodybuilding supplement, Huperzine A is added to boost focus during workout.
Bioavailability and Abosrption
Orally administered huperzine A starts to appear in plasma after 5-10 minutes and reaches a peak concentration at about one hour . This  and one other study  reported rapid absorption and distribution with moderate elimination rate. Huperzine A has high oral bioavailability (96.9% in mice ) .
Effects of Huperzine A on Mental Functions
Huperzine A is reversible, potent, and selective anticholinesterase (the enzyme responsible for the breakdown of acetylcholine) inhibitior [4-6,18]. As a result, more acetylcholine is available in the brain, thus increasing the efficacy of the remaining cholinergic neurons.
Signifianlty improved cognition was repored in 78 patients with mild to moderate vascular dementia when compared to placebo . In 34 adolescent students complaining of memory inadequacy enhanced memory and learning performance was markedly elevated after 4 weeks of 50 mcg of huperzine A administration .
Treatment of Alzheimer’s Disease
A review (6 trials with a total 454 patients)  evaluating huperzine A for treatment of Alzheimer’s disease reported that huperzine A is superior to placebo for patients with AD. Huperzine A appeares to improve global cognitive function, behavioral disturbance, and functional performance. However, most studies included in a review were of a poor methodological quality. A more recent review (2011)  concluded that the current clinical evidence in support of the use of huerzine A in AD is still inconclusive or inadequate.
One high-quality large-scale randomized controlled trial  reported remarkably improved cognition, behavior and mood in patients with mild to moderate AD. However, in this study Huperzine A was stacked with Vitamin E which might have tiggered a synergistic effect. Furthermore, phase IV clinical trials in China reported siginificantly improved memory of elderly people and patients with Alzheimer’s disease and vascular dementia [19-22].
Preclinical and clinical findings suggest that HupA is a promising candidate for the treatment of neurodegenerative diseases [18,23].
Studies [12,13,23] even reported that Huperzine A scavenges free radicals in the brain.
Huperzine A as Bodybuilding Supplement
As a bodybuilding suplements huperzine A is used to boost focus during workouts. However, no studies examined its direct effect for this purpose nor were effects of huperzine A (or other anticholinesterase inhibitiors ) adequately examined in healthy population.
Acetylcholine is also a critical neurotransmitter for muscle contractions . Therefore, huperzine A was reported to significantly increase the amplitude of muscle contraction induced by stimulating nerve .
Works Well With…
Huperzine A is often stacked with choline (such as alpha-glyceryl phosphoryl choline [Alpha-GPC]) to further elevate the levels of neurotransmitter acetylcholine.
Typical dose of huperzine A in bodybuilding supplements is 50 mcg. This dose also sufices for increased memory and learning . Doses for AD treatment range from 200 to 500 micro g/day [11,17].
Side Effects and Toxicity
No serious adverse effects were reported in patients with AD after huperzine A administration . In a study by Zhang Z et al.  huperzine A was regarded as safe. Animal and clinical safety tests showed that HupA had no unexpected toxicity .
(Other common names: Huperzina A, Huperzine, Huperzine-A, Selagine)
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