Huperzine-A boosts cognition


David Tomen
David Tomen
11 minute read
Huperzine-A improves cognition, memory, learning, recall, is an antioxidant, helps neuroplasticity, and protects against glutamate-toxicity.

Huperzine-A (Hup-A) is a water-soluble alkaloid nootropic derived from Chinese Club Moss (Huperzia serrata). This plant is native to southeast Asia. And has been used in traditional medicine for millennia to treat skin conditions, muscle problems and to boost blood circulation.

Huperzine-A is a reversible natural acetylcholinesterase inhibitor (AChE). Which means it prevents the breakdown down of acetylcholine (ACh). Boosting short-term memory and long-term brain health. But will stop its action on acetylcholine as soon as you stop using it.

Huperzine-A also seems to be a NMDA receptor antagonist. Which is beneficial in that it prevents an excess of glutamate from damaging brain cells.

Huperzine-A helps:

  • Neurotransmitters: Huperzine-A prevents the enzyme AChE from breaking down acetylcholine. Improving cognition and memory.
  • Brain Energy: Huperzine-A supports brain cell mitochondria. The primary energy sources fueling brain cells and brain cell function.
  • Neuroprotectant: Huperzine-A works as an antioxidant and boosts the activity of other brain antioxidants. Preventing free radical damage and induced oxidative injury. And boosting brain cell longevity.


Huperzine-A (Hup-A) is a water-soluble natural plant alkaloid nootropic that easily crosses the blood-brain barrier.


Hup-A is derived from Chinese Club Moss (Huperzia serrata). A plant native to southeast Asia where it’s been used in traditional medicine for thousands of years.

Huperzine-A has a strong inhibitory effect on acetylcholinesterase (AChE). This enzyme AChE, is responsible for degrading the neurotransmitter acetylcholine (ACh).

Boosting levels of acetylcholine (ACh) transmission in your brain improves memory and attention. And promotes greater neuroplasticity which is necessary for long-term memory formation and general brain cell health.

Huperzine-A is also a NMDA receptor antagonist. This glutamate receptor’s job is to control synaptic plasticity and memory function. Which is a positive thing. But blocking its function can also be effective at times. By preventing damage from too much glutamate.  And blocking the toxicity from certain nerve agents.[i]

This combination of boosting acetylcholine and blocking NMDA receptors requires a fine balance. And could explain why it’s beneficial to cycle the use of Huperzine-A. To maintain the delicate balance of neurochemistry in the brain while realizing Huperzine-A’s benefits.

Huperzine-A vs. Huperzia serrata: What’s the Difference?

Huperzine-A vs Huperzine serrataHuperzine-A (Hup-A) is produced in the lab from Huperzia serrata (a natural Chinese Herbal Medicine called Chinese Club Moss). Huperzine-A is a standardized compound found in this naturally occurring plant.

Note that Huperzine-A and Huperzia serrata are NOT the same supplement.

Some nootropic supplement stacks substitute genuine Huperzine-A with Huperzia serrata. All the research I’ve seen uses Huperzine-A in their clinical trials. Not Huperzia serrata.

Look for a supplement with genuine Huperzine-A on the label. And avoid stacks or supplements that use Huperzine serrata.

Huperzine-A is an acetylcholinesterase inhibitor.

How does Huperzine-A Work in the Brain?

Huperzine-A boosts brain health and function in several ways. But two in particular stand out.

  1. Huperzine-A acts as an acetylcholinesterase inhibitor. Acetylcholinesterase (AChE) is an enzyme that breaks down the important neurotransmitter acetylcholine once it’s used in your system. So Hup-A helps prevent this breakdown. Allowing more acetylcholine to be available which improves learning and memory.

Scientists at the Weizmann Institute in Israel uncovered how Huperzine-A works to block this novel acetylcholinesterase inhibitor. They made a 3-D image of the structure of the AChE molecule. And found a deep chasm, called the “active-site gorge”.

The scientists found the active-site gorge acts like a guide to funnel acetylcholine into the interior of the enzyme where it is cut apart prior to recycling. This is how AChE blocks acetylcholine from being eliminated.

The study revealed that Huperzine-A has the unique ability to fit into this active-site gorge. Like a key into a lock. And appears to bind more tightly and specifically to AChE than other AChE inhibitors.

This ability for Huperzine-A to take acetylcholine’s place within the AChE enzyme is how more acetylcholine is made available in the brain.

Professor Joel Sussman said, “It is as if this natural substance were ingeniously designed to fit into the exact spot in AChE where it will do the most good.”[ii]

  1. Huperzine-A also plays a neuroprotective role. Researchers discovered that Hup-A prevents glutamate-induced toxicity. Protecting the hippocampus and other cerebral neurons from cell death caused by the amino acid glutamate.[iii]

In addition to protecting from glutamate-induced toxicity, Huperzine-A also promotes new dendrite growth in neurons.[iv]

How things go bad

As we get older, our brain chemistry and metabolism changes.

↓ Acetylcholine levels decline

↓ Concentration, attention and mental agility decline

↓ Nerve growth factor declines

↓ Free radicals damage brain cell mitochondria

All of these changes can happen at any age. And are a product of the food we eat, what we drink, lifestyle habits, the air we breathe and more.

So Huperzine-A can help for age-related cognitive decline, as well as a student looking to do better in school. By boosting the availability of acetylcholine in your brain.

Huperzine-A benefits

Huperzine-A benefits

Huperzine-A boosts acetylcholine

Huperzine-A boosts levels of available acetylcholine in the brain by blocking the effect of the enzyme acetylcholinesterase (AChE).

Acetylcholine (ACh) is critical for encoding new memories, reasoning, concentration, cognition, and neuroplasticity. Not enough ACh can result in diseases like ADHD, Alzheimer’s and other neurodegenerative diseases.

Huperzine-A’s benefit as a nootropic can boost short-term mental function like attention and memory. And even helping your brain for long-term brain health.

Huperzine-A is an antioxidant

Huperzine-A supports brain cell mitochondria. The main energy centers of each cell. It reduces free radical damage by acting as an antioxidant. Free radicals degrade mitochondria and their function. Studies have shown that Hup-A enhances the activities of other antioxidant enzymes as well.[v]

Huperzine-A resists beta-amyloid dysfunction

Huperzine-A boosts neuron resistance to beta-amyloid induced dysfunction that could lead to diseases like Alzheimer’s. Beta-amyloid affects ATP levels in mitochondria. Hup-A protects against this damage.[vi]

Huperzine-A prevents glutamate toxicity

Huperzine-A protects brain cells from glutamate toxicity. Too much of the neurotransmitter glutamate has been associated with brain cell degeneration. And other cognitive dysfunction and behavior. Hup-A seems to slow down this glutamate toxicity at least partly by acting as a NMDA receptor ion channel antagonist.[vii]

Huperzine-A increases nerve growth factor

Huperzine-A boosts nerve growth factor (NGF) in the brain. NGF is critical in brain cell development, maintenance and repair. Declines in NGF-levels in the brain are associated with Alzheimer’s and other neurodegenerative diseases. Studies show Hup-A not only prevents this drop in NGF from happening. It actually helps boost the production of NGF.[viii]

How does Huperzine-A feel?

Nootropics users report Huperzine-A provides a boost in mental energy. Without the side effects normally associated with a stimulant.

Improved cognition and clear thinking are common when using Hup-A. Many report a boost in short-term memory. Recall is better in the long-term.

And some with Alzheimer’s report the progression of the disease slows down. Instead of advancing.

You should be able to experience the effects of Huperzine-A soon after you take it. It’s water-soluble so it’s digested and enters your cells quickly.

One thing to note is; Huperzine-A has a long half-life of 10 – 14 hours. In other words, it does not leave your system nearly as quickly as most other nootropics. So many neurohackers restrict their use of Hup-A to 2 or 3-times per week.

Huperzine-A is an antioxidant and neuroprotectant

Huperzine-A Clinical Trials and Research

Huperzine-A is most known for boosting acetylcholine (ACh) in the brain. Efficient ACh neurotransmission is critical for learning, memory and attention.

Reduced levels of ACh can cause cognitive deficits like a decline in memory. And are implicated in several neurodegenerative diseases including Alzheimer disease, Parkinson’s, ALS and others.

Huperzine-A supplementation helps even in those with no sign of brain disease. It can enhance attention and memory in most looking to boost cognition.

Huperzine-A Provides Protection in Chemical Warfare

If you ever find yourself in a war-zone, you may want to stock up on Huperzine-A.

Researchers at the Walter Reed Army Institute of Research in Washington D.C. are investigating Huperzine-A’s potential as a pretreatment to protect soldiers against chemical warfare nerve agent toxicity.

One of the studies conducted at Walter Reed looked at Huperzine-A’s protective potential. Scientists found Hup-A to be twice as effective in protecting against the lethal effects of the nerve agent soman as the leading drug in that role called physostigmine. Huperzine-A’s effects lasted for six hours compared to only 90 minutes for the drug.[ix]

Huperzine-A Improves Learning & Memory

This study is verification of using Huperzine-A as a nootropic at any age. Researchers in China selected 68 students who complained of bad memory. And their learning performance was getting worse in school.

In this double-blind, placebo-controlled trial students were given either 100 mcg of Hup-A or a placebo for 4 weeks.

At the conclusion of the trial, researchers found that the students using Huperzine-A scored higher on memory testing than those who took the placebo.[x]

Huperzine-A Improves Cognition

Much of the research on Huperzine-A has been done in China. And many of the studies have been with patients suffering from neurodegenerative diseases like Alzheimer’s.

In one of the randomized clinical trials done in Shanghai, researchers worked with 200 patients who met the criteria for having Alzheimer Disease therapy. Researchers gave one group of patients 300-500 mcg of Hup-A daily for 8 – 24 weeks. The other group got a placebo.

The results of the study showed that Huperzine-A’s effects increased over time. The patients that used Hup-A showed significant improvements in cognition, orientation, attention, memory, mood, and assisting participants with vascular dementia.[xi]

Huperzine-A Recommended Dosage

Recommended Huperzine-A dosage is 50 – 200 mcg every second or third day. Hup-A is water-soluble so you don’t need to take it with a meal, or healthy fat like some nootropics.

Huperzine-A dosageHuperzine-A is typically sold as 50, 100, or 200 mcg tablets or capsules. Several retail nootropic stacks often include Huperzine-A in their formula. So you should not supplement with more Hup-A while using these pre-made stacks.

Since Huperzine-A has at least a 10 – 14 hour half-life most neurohackers prefer cycling. This means using Hup-A every 2nd day, or even only twice per week.

Huperzine-A is also available as an injection for therapeutic use. Typically used for the treatment of Alzheimer’s disease. Or the muscle weakness condition called myasthenia gravis.

Huperzine-A Side Effects

Huperzine-A can be toxic if used in larger than recommended doses. Or if you already have too much acetylcholine(ACh) in your system. Remember, Hup-A boosts levels of ACh.

Side effects with Huperzine-A are rare but can include symptoms similar to choline-overload like nausea, vomiting, diarrhea, insomnia, anxiety, dizziness, thirst and constipation.

Very rarely will Huperzine-A cause cardiac arrhythmia.

Symptoms of acute toxicity are similar to those of other cholinergic inhibitors. And can include muscle tremors, drooling, tears, bronchial mucous and incontinence.

Do not use Huperzine-A if you’re dealing with epilepsy. And if you have heart disease, use Hup-a with caution. It can slow heart rate.

Huperzine-A may make asthma or emphysema worse. Because it can cause mucous in the lungs. The same goes for those dealing with urinary tract or reproductive system blockages. It can cause mucous buildup there as well.

An important note for Alzheimer’s patients: Huperzine-A can increase the effects of drugs you may already be taking. Talk to your doctor before trying Hup-A.

Types of Huperzine-A to Buy to Enhance Cognitive Function

Huperzine-A is sold in tablet or capsule form. Tablets and capsules are usually 50 – 200 mcg each.

Be careful with pre-made nootropic stacks containing Huperzine-A where the manufacturer recommends daily use. Because Huperzine-A should only be used every 2nd or 3rd day because of its 10 – 14 hr. half-life.

Huperzia serrata is simply raw, powdered Chinese Club Moss and should be avoided. It’s not standardized so you don’t know how much you’re getting. And it’s NOT the same as Huperzine-A.

Nootropics Expert Recommendation

Huperzine-A 200 mcg every 2nd or 3rd day

Nootropics Expert Tested and ApprovedI recommend using Huperzine-A as a nootropic supplement with caution.

Your body does not make Huperzine-A on its own. So to get its benefits you must take it as one of your dietary supplements.

Huperzine-A is especially helpful for those suffering from cognitive dysfunction caused by diseases like Alzheimer’s.

Huperzine-A is also particularly useful to students and executives who want to boost cognition, learning and memory.

Huperzine-A is a fast-acting nootropic that can also help prevent brain degeneration later in life.

Huperzine-A does have a long 10 – 14 hr. half-life so you should cycle it. Either take it every 2nd day, or even twice per week. The benefits are long-lasting and will stay with you.

As an Amazon Associate I earn from qualifying purchases. This post may also contain other affiliate links and I will be compensated if you make a purchase after clicking on my links.

[i] Coleman B.R., Ratcliffe R.H., Oguntayo S.A., Shi X., Doctor B.P., Gordon R.K., Nambiar M.P. “[+]-Huperzine A treatment protects against N-methyl-D-aspartate-induced seizure/status epilepticus in rats.” Chemico-Biological Interactions. 2008 Sep 25;175(1-3):387-95. (source)

[ii] Raves M.L., Harel M., Pang Y.P., Silman I., Kozikowski A.P., Sussman J.L. “Structure of acetylcholinesterase complexed with the nootropic alkaloid, (-)-huperzine A.” Nature Structural Biology. 1997 Jan;4(1):57-63. (source)

[iii] Gordon R.K., Nigam S.V., Weitz J.A., Dave J.R., Doctor B.P., Ved H.S. “The NMDA receptor ion channel: a site for binding of Huperzine A.” Journal of Applied Toxicology. 2001 Dec;21 Suppl 1:S47-51. (source)

[iv] Shen J.N., Wang D.S., Wang R. “The protection of acetylcholinesterase inhibitor on β-amyloid-induced injury of neurite outgrowth via regulating axon guidance related genes expression in neuronal cells” International Journal of Clinical and Experimental Pathology. 2012; 5(9): 900–913. (source)

[v] Xiao X.Q., Wang R., Han Y.F., Tang X.C. “Protective effects of huperzine A on beta-amyloid(25-35) induced oxidative injury in rat pheochromocytoma cells.” Neuroscience Letters. 2000 Jun 9;286(3):155-8. (source)

[vi] Gao X., Tang X.C. “Huperzine A attenuates mitochondrial dysfunction in beta-amyloid-treated PC12 cells by reducing oxygen free radicals accumulation and improving mitochondrial energy metabolism.”Journal of Neuroscience Research. 2006 May 1;83(6):1048-57. (source)

[vii] Hynd M.R., Scott H.L., Dodd P.R. “Glutamate-mediated excitotoxicity and neurodegeneration in Alzheimer’s disease.”Neurochemistry International. 2004 Oct;45(5):583-95. (source)

[viii] Tang L.L., Wang R., Tang X.C. “Effects of huperzine A on secretion of nerve growth factor in cultured rat cortical astrocytes and neurite outgrowth in rat PC12 cells.” Acta Pharmacologica Sinica. 2005 Jun;26(6):673-8. (source)

[ix] Saxena A., Qian N., Kovach I.M., Kozikowski A.P., Pang Y.P., Vellom D.C., Radić Z., Quinn D., Taylor P., Doctor B.P. “Identification of amino acid residues involved in the binding of Huperzine A to cholinesterases.” Protein Science. 1994 Oct;3(10):1770-8. (source)

[x] Sun Q., et. Al. “Huperzine-A capsules enhance memory and learning performance in 34 pairs of matched adolescent students” Acta Pharmacologica Sinica 1999; (7):601—603 (source)

[xi] Wang B.S., Wang H., Wei Z.H., Song Y.Y., Zhang L., Chen H.Z. “Efficacy and safety of natural acetylcholinesterase inhibitor huperzine A in the treatment of Alzheimer’s disease: an updated meta-analysis.”Journal of Neural Transmission (Vienna). 2009 Apr;116(4):457-65. (source)

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Join The Discussion - 187 comments

Kyle Scott
February 15, 2024

Can I combine this with Vinpocetine?

    David Tomen
    February 15, 2024


February 12, 2024

I’m sorry I meant 50 mcg three times a week

    David Tomen
    February 13, 2024

    OK. 50 mcg Huperzine-A taken only 3-times per week is safe.

      March 8, 2024

      Dave: I have been taking 50 mcg three times a week for 3 three weeks now. A week ago I started experiencing a floating sensation and occasional lightheadedness. Is this Huperzine or something else? Will reducing it to 2 days help?

        David Tomen
        March 9, 2024

        Patt, Huperzine-A has a 14 hour half life. Which means that if you use it every day it builds up in your system eventually toxic levels. 3-times per week should work for most people. But it sounds like it may take longer to clear from your system.

        Keep in mind the acetylcholinesterase inhibitors that work just like Huperzine-A are used in biological warfare very successfully. Huperzine-A is a very potent nootropic so I suggest you quit using it for a week or two. And then if you want to keep using it only do it max. twice per week.

Patt Lennon
February 12, 2024

I have tinnitus and I have noticed when I take Huperzine-A the tinnitus is down a few notches. Is it okay to take 50 mg every other day? I was already taking choline before I found this supplement. Should I stop taking Choline?

    David Tomen
    February 12, 2024

    Patt, the maximum recommended dosage of Huperzine-A is 200 mcg. 50 mg is a much much higher dose than recommended so I cannot say it is Okay to use. And it depends on what form of “choline” you are using. If it is something like CDP-Choline or Alpha GPC that will potentiate the way Huperzine-A works.

      February 12, 2024

      It’s Choline bitartrate 180 mg once daily

        David Tomen
        February 13, 2024

        Patt, Choline bitartrate 180 mg will not do anything for you. It is a very small dose and cannot cross the blood-brain barrier.

        February 14, 2024

        should i increase it to twice a day? if not, what form should I take in a small dose, i am sensative to supplements

        David Tomen
        February 14, 2024

        Patt, 50 mcg Huperzine-A is an effective dose and there is no need to use it twice per day. Because one dose lasts 24 – 28 hours after which it leaves your system.

        February 15, 2024

        I was referring to choline, not huperzine, what form of choline do you suggest that crosses the brain barrier in a low dose? I am sorry for any confusion.

        David Tomen
        February 15, 2024

        Patt, the safest long-term choline supplement is CDP-Choline 300 mg twice per day.

        February 16, 2024

        thank you so much

        patt lennon
        April 4, 2024

        I have been taking Huperzine 50 mcg twice a week now for a month and it works. However, I had GAD and I find that Huperzine increases anxiety and I have been experiencing an increase in inbalance side effects. What other nootropics can I take with fewer side effects?

        David Tomen
        April 4, 2024

        Patt, Huperzine-A is a very potent acetylcholinesterase inhibitor. And side effects can cause symptoms similar to choline-overload like nausea, vomiting, diarrhea, insomnia, anxiety, dizziness, thirst and constipation.

        I have reviewed 102 nootropic supplements on Nootropics Expert. So, I cannot recommend anything until I know what you are trying to achieve with nootropics. Why did you decide to use Huperzine-A in the first place? That could be a good start in figuring out what may help you.

        patt lennon
        April 5, 2024

        I am an endurance athlete and over the age of 55. I take many supplements and eat a very clean diet. I have had several friends and parents of friends who have Alzheimer’s. I have a healthy concern for the disease. I do not have any signs of decline, however, I suffer from tinnitus and it can make you feel like you are dragging mentally and mentally spacy. I have experienced a decline in tinnitus perception on both Huperzine and Choline which is wonderful. I stopped the Huperzine A and within two days the side effects subsided. I started taking CDP Choline a few days ago and the only side effect I am experiencing is some slight jitters. I am very alert and increased energy.

        David Tomen
        April 8, 2024

        Patt, CDP-Choline works in synergy with ALCAR to produce acetylcholine. Try adding 500 mg ALCAR and see if that helps. You may even be able to cut your CDP-Choline dose in half if needed once you add ALCAR.

        patt lennon
        April 9, 2024

        great suggestion, thank you, how about GABA for the anxiety?

        David Tomen
        April 10, 2024

        Patt, try Lemon Balm extract for anxiety.

        patt lennon
        April 11, 2024

        Thanks, David, I have tried lemon balm and it gave me nausea. However, I tried 125 mg of gaba the last two days and I love it. It worked within an hour and lasted most of the day without side effects. I feel so calm without the drowsy effects. Do you not prefer Gaba?

        David Tomen
        April 12, 2024

        Patt, I need to supplement with GABA because otherwise I am deficient. I use PharmaGABA.

October 28, 2023

Hello David,
i can not read all the comments after the new design of your website, for example here are 162 comments if i switch between the sites below from 1-8 i come back to the comments which i already read, i wanted to mention that to you, because it helps us reading the experiences.

Thank you.

    David Tomen
    October 30, 2023

    Alen, noted and I sent a message to my developer to find a solution. Thanks for bringing this to my attention.

September 30, 2023

Hello David,

does Huperzine A work similarly to Racetams, because i did take it 2 days a week but not with choline supplements, in some days it worked very well for cognitive improvement, but sometimes it made me sleepy and energyless, so does this mean that maybe not enough acetylcholine was available to be reused ?

Thanks a lot.

    David Tomen
    October 1, 2023

    Rooney, Huperzine-A does not work anything like any of the racetams. Huperzine-A is an acetylcholinesterase inhibitor which means you end up reusing the acetylcholine that your system already used. But Huperzine-A has a very long half life. Usually 12 – 14 hours. So it will take a day or two to clear from your system. This is why I recommend only using Huperzine-A every 2nd or 3rd day. It sounds like you used it a little too often and you got those side effects.

    But depending on your age you are likely deficient in acetylcholine anyway. Everyone else is as they get older. This is why it is a good idea to use 300 mg CDP-Choline twice per day with 500 mg ALCAR twice per day along with a bioactive Multi or B-Complex.

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