The chemical action of huperzine A is very precise and specific. Because huperzine A is in the way, the enzyme can't grab and destroy acetylcholine. This mechanism has been demonstrated by considerable scientific work, including sophisticated computer modeling of the shape of the molecule. Although it originally comes from a plant, huperzine A is highly purified in a laboratory and is just a single chemical. It is just not much like an herb.
Herbs contain hundreds or thousands of chemicals.
We recommend using it only under a doctor's supervision. Perhaps because it works so specifically, huperzine A appears to have few side effects. However, children, pregnant or nursing women, or those with high blood pressure or severe liver or kidney disease should not take huperzine A except on a doctor's recommendation. We also don't know whether huperzine A interacts adversely with any drugs. Zhang RW, et al.