Huperzine A: Health Benefits, Uses, Side Effects & Dosage
Huperzine A is a compound that comes from the Chinese club moss Huperzia serrata. It works as a potent memory enhancer, and it may also have benefits for people with Alzheimer disease.
It seems to work by protecting the brain from age-related destruction of neurons, or nerve cells, that form memories. Huperzine A has not been well studied in humans. However, it has been used for many years in Asia with few reported side effects.
It appears to be safe when taken by mouth or injection into the muscle. Animal studies show that it can improve memory and slow down age-related nerve cell death in the brain.
In some people, memory problems may be helped by taking Huperzine A. It is thought to work in part by protecting neurons from damage that occurs when they are exposed to harmful substances or waste products. The exact mechanism by which Huperzine A improves memory is not clear; it may be linked to the way it boosts levels of a brain chemical called acetylcholine, which helps control alertness and memory.
The amount of Huperzine A needed to benefit people with memory problems is not clear, so the usual dose of the supplement varies. It has been taken for several years in Asia as a tonic drink or in capsule form.
Huperzine A is usually taken at night before bedtime at the recommended dosage of about one drop (0.02 ml) per day, following the instructions on the label. Higher doses have not been used for long periods without serious side effects reported; heavy doses also seem to affect blood pressure and cause insomnia.
How does it work?
The chemical structure of huperzine A closely resembles that of the neurotransmitter acetylcholine (ACh).
Its function is similar to that of another cholinesterase inhibitor called tacrine. Tacrine was approved by the US Food and Drug Administration (FDA), for use in treating Alzheimer's disease, but has since been withdrawn due to its adverse side effects profile.
Huperzine A may represent an alternative approach to inhibiting activity of acetylcholinesterase because there is less interference with cholinergic activity at doses needed for memory enhancement.
There was some potential for hepatotoxicity when taking huperzine A, however, more recent research has shown that it does not appear to be any riskier than many of the other cholinesterase inhibitors approved for use.
The mechanism of action of huperzine A has been studied primarily in in vitro brain slices. In these studies, the substance appears to work as an inhibitor of acetylcholinesterase; that is, it prevents the breakdown of acetylcholine (ACh) in the brain.
Animals treated with huperzine A have shown improvement in cognitive function, behavioral change (such as increased mobility and social interaction), and an improvement in memory-related behavior. The mechanism by which these effects occur is not known and may involve changes in the cholinergic system or glutamate (a neurotransmitter).
Since Huperzine A is a cholinesterase inhibitor it affects the breakdown of a neurotransmitter called acetylcholine.
Acetylcholine is thought to play a role in learning and memory. It also controls the transmission of nerve impulses in the brain, which may be important for cognition and behavior.
Acetylcholine is produced by neurons in many parts of the brain as well as the peripheral nervous system (PNS). Its breakdown by cholinesterase is controlled by an enzyme that acts on acetylcholine, called acetylcholinesterase (AChE), which can be found at high levels in some parts of the brain but not others.
The current thinking is that Huperzine A binds to this enzyme and prevents it from working properly; this way, it increases brain levels of acetylcholine without interfering with other processes.
Uses & Effectiveness
Huperzine A is often taken as a supplement by people who want to improve memory and brain function. It has been used in China for centuries.
It is also being studied in rats with Alzheimer's disease and in other animals to see if it can help protect against nerve cell damage in the brain caused by drugs, toxins, or lack of oxygen; due to aging; or because of injury. Research is lacking on the use of Huperzine A for Alzheimer's disease.
There have been some reports of side effects from Huperzine A, including symptoms like:
- Nausea
- Vomiting
- Diarrhea
- Stomach pain
- Dry mouth
- Trouble sleeping
- Anxiety or restlessness (especially at high doses)
- Mmuscle spasms (especially at high doses)
- Sweating, dizziness or shakiness (usually at the beginning of treatment).
These side effects are uncommon; it may be that nausea and vomiting are more likely with higher doses than with lower ones.
Dosage & When To Use It
The standard recommended dose is 0.02 ml three times daily (0.06 ml total per day). The maximum dosage appears to be 0. 5 ml, taken preferably at bedtime. It is important to understand how much Huperzine A to take so that the dose can be adjusted for best results. Higher doses of the supplement have not been used for many months without serious side effects reported.
There have been reports of hepatotoxicity (liver damage) when taking Huperzine A, especially at higher doses. If symptoms are seen, they should be reported to a doctor right away.
Huperzine A does not seem to affect blood pressure in most people when taken at recommended doses; however, it may cause a small increase in blood pressure if taken in overdose or if the dosage is too high. Rarely this may cause dizziness or fainting.
As with other cholinesterase inhibitors (like tacrine), Huperzine A can sometimes cause trouble sleeping when starting treatment; low doses will usually work well enough for most people that it only takes a few days to get them adjusted before all is well again.
It is important for patients to be aware of the possibility of side effects if they should occur, and adjusting the dosage downward may help reduce or eliminate them. The majority of side effects are mild and may subside with time.
Huperzine A seems to work best when taken at bedtime because it is excreted through the urine during the night hours if nocturia (being unable to sleep because of frequent trips to urinate) occurs. This may be beneficial due to the fact that it allows Huperzine A to be metabolized more quickly by the body so that there is a higher concentration available during its peak performance time, which would be at night while sleeping.
Because Huperzine A remains in blood plasma for only about 2 hours after dosing near bedtime, there is a need to adjust dosing with consideration for each persons own unique metabolism.
The supplement can also increase cognitive function in some people who use it. The effects are reversible when the dosage is lowered.
Huperzine A appears to be safe when taken by mouth or injection into the muscle as long as it is not immediately after eating or drinking.
In Summary
Huperzine-A is a natural compound that comes from the Chinese club moss Huperzia serrata. It works as a potent memory enhancer, and it may also have benefits for people with Alzheimer disease.
It seems to work by protecting the brain from age-related destruction of neurons, or nerve cells, that form memories. Huperzine A has not been well studied in humans. However, it has been used for many years in Asia with few reported side effects.
It appears to be safe when taken by mouth or injection into the muscle. Animal studies show that it can improve memory and slow down age-related nerve cell death in the brain.
In some people, memory problems may be helped by taking Huperzine A. It is thought to work in part by protecting neurons from damage that occurs when they are exposed to harmful substances or waste products. The exact mechanism by which Huperzine A improves memory is not clear; it may be linked to the way it boosts levels of a brain chemical called acetylcholine, which helps control alertness and memory.
The amount of Huperzine A needed to benefit people with memory problems is not clear, so the usual dose of the supplement varies. It has been taken for several years in Asia as a tonic drink or in capsule form.
Huperzine A is usually taken at night before bedtime at the recommended dosage of about one drop (0.02 ml) per day, following the instructions on the label. Higher doses have not been used for long periods without serious side effects reported; heavy doses also seem to affect blood pressure and cause insomnia.
References:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4137276/ ("Huperzine A: Is it an Effective Disease-Modifying Drug for Alzheimer’s Disease?")
- https://pubmed.ncbi.nlm.nih.gov/27086593/ ("Huperzine A as a neuroprotective and antiepileptic drug: a review of preclinical research")
- https://pubmed.ncbi.nlm.nih.gov/12895686/ ("The psychopharmacology of huperzine A: an alkaloid with cognitive enhancing and neuroprotective properties of interest in the treatment of Alzheimer's disease").
- https://pubmed.ncbi.nlm.nih.gov/15956816/ ("Neuroprotective effects of huperzine A. A natural cholinesterase inhibitor for the treatment of Alzheimer's disease").