Club Moss, particularly Huperzia serrata, has a long history of use in traditional Chinese medicine for improving memory and cognitive function. The active compound in Club Moss, huperzine A, is an acetylcholinesterase inhibitor, meaning it can block the enzyme that breaks down acetylcholine, a key neurotransmitter involved in memory and learning. This traditional use has led to its inclusion in supplements aimed at supporting the acetylcholine system in the body.

While there is some preliminary scientific research supporting huperzine A's effects on acetylcholine levels and cognitive performance, particularly in the context of Alzheimer’s disease, the majority of evidence remains limited to animal models, small clinical trials, and traditional usage. Because of this, the primary justification for using Club Moss to support the acetylcholine system is traditional, with some emerging but not yet robust scientific support.

Thus, while Club Moss is traditionally used for cognitive health, and there is some mechanistic rationale for its effect on the acetylcholine system, the overall evidence is moderate and not yet definitive.