Huperzine A: Uses, Benefits, and More

Huperzine A is a chemical found in Chinese club moss (Huperzia serrata, or H. serrata). Huperzine A is used in traditional Chinese medicine.

Huperzine A is a natural version of an acetylcholinesterase inhibitor. Acetylcholinesterase is a protein that breaks down a naturally occurring brain chemical called acetylcholine (ACH). By blocking acetylcholinesterase, huperzine A is thought to increase ACH levels, which tend to be low in people with Alzheimer's disease (AD). This is how Aricept (donepezil) also works as a treatment option for AD.

Huperzine A may have potential nootropic effects, meaning it might support brain health, such as memory. It is an approved medication in some countries, such as China, but the Food and Drug Administration (FDA) hasn't approved huperzine A as a prescription product in the United States.

This article will cover what you should know about huperzine A—its potential uses, side effects, and interactions.

Uses of Huperzine A

As with many natural products, more extensive research is necessary to guarantee safety and efficacy.

People use huperzine A for various reasons, including to aid in Alzheimer's disease and vascular dementia.

Alzheimer's Disease

Two systematic reviews and meta-analyses studied huperzine A's potential use in people with Alzheimer's disease.

Results from the studies in both of these reviews suggest that huperzine A might help people with AD in the following ways:

• Brain function
• Ability for self-care—like eating or getting dressed—for a longer period of time
• General improvement in ability as shown in healthcare providers' assessments

In addition to these two studies, a 2014 meta-analysis on huperzine A for AD in Evidence-Based Complementary and Alternative Medicine echoes the benefits for use in people with Alzheimer's disease. In the studies, huperzine seemed to help people with AD perform better on a brain function exam—in addition to successfully performing activities of daily living (ADLs), such as eating and getting dressed.

While these results are positive, extensive and high-quality research with larger and longer-term studies is still necessary to better assess huperzine A's effects and safety in people with AD.

Vascular Dementia

People with vascular dementia have medical conditions that affect the blood vessels in the brain. These medical conditions may result in memory problems. People with vascular dementia may also experience changes in thinking and behavior.

An older systematic review from 2009 of huperzine A's potential use for vascular dementia was conducted. Among the studies in this review, only one small clinical trial was conclusive.

Based on this one study, huperzine A didn't do better than placebo (a substance with no therapeutic benefit) in terms of improving scores on a brain function exam. But after six months, huperzine A did seem to help people with vascular dementia on ADLs.

Since the results of this small study were mixed, no firm conclusion can be made about huperzine A for vascular dementia. Additional, well-designed clinical trials are still necessary to evaluate huperzine A's effects better.

The aforementioned meta-analysis published in Evidence-Based Complementary and Alternative Medicine was larger and analyzed a collection of studies on huperzine's effects on AD and vascular dementia. This meta-analysis concluded that huperzine A may benefit people with vascular dementia.

In addition to doing better on ADLs, study participants with vascular dementia also improved on a brain function exam and experienced fewer side effects from huperzine A than those with AD.

Although the results from the meta-analysis were positive, additional high-quality clinical trials with a larger group of study participants are still necessary to evaluate huperzine A's effects.

What Are the Side Effects of Huperzine A?

Like many medications and natural products, side effects are possible with huperzine A.

Common Side Effects

Most side effects have been mild and temporary.

Common side effects include:

• Blurred vision
• Constipation
• Diarrhea
• Dizziness
• Dry mouth
• Nausea and vomiting
• Sleeping problems
• Slow heart rate
• Stomachache
• Sweating
  

Severe Side Effects

There is little information on the safety of huperzine A. However, in more than one systematic review and meta-analysis, there were no reported severe side effects.

All medications and even supplements can pose a risk of severe allergic reaction. If you're having a severe allergic reaction to huperzine A, symptoms may include breathing difficulties, itchiness, and rash.

Call 911 and get medical help immediately if you're having a severe allergic reaction or if any of your symptoms feel life-threatening.

Precautions

A healthcare provider may advise against using huperzine A if any of the following applies to you:

Severe allergic reaction: If you have a severe allergic reaction to huperzine A or its components (ingredients), do not take this substance.

Pregnancy and breastfeeding: There are likely no huperzine A product labels that target pregnant or breastfeeding parents. Moreover, there is little data about the effects and safety of huperzine A while pregnant or breastfeeding. However, in animal studies, taking Aricept—a prescription medication that has cholinesterase inhibitor effects (like hupezine A)—late in pregnancy was linked to negative effects on the unborn fetus.

For these reasons, contact a healthcare provider to discuss the benefits and risks before taking huperzine A.

Children: Most huperzine A product labels target adults—not infants or children. Talk with a healthcare provider if you're considering huperzine A for your child.

Adults over age 65: While older adults participated in some huperzine A-related clinical trials, additional and extensive research is still necessary to determine safety in this population. Moreover, some older adults may have a greater likelihood of medication side effects. For this reason, take huperzine A with caution.

Low weight: People under 121 pounds are more likely to experience side effects from Aricept, a human-made cholinesterase inhibitor with effects similar to huperzine A.

Dosage: How Much Should I Take Huperzine A?

While there are some studies on huperzine A in humans, more high-quality clinical trials are still necessary. For this reason, there are no guidelines on the appropriate dosage of huperzine A to take for any condition.

In clinical trials for Alzheimer's disease, however, the total daily dose (TDD) range was 0.2–0.8 milligrams (mg). For vascular dementia, the TDD range was 0.1–0.3 mg. Generally, a dosage of 0.4 mg twice daily for up to 24 weeks was well-tolerated.

More consistent and reliable information is still necessary. Follow a healthcare provider's recommendations or label instructions before choosing a dose for huperzine A.

What Happens If I Take Too Much Huperzine A?

There is little information about huperzine A safety, toxicity, and overdoses in humans. But symptoms of overdose with huperzine A are likely to be similar to its potential common and serious side effects, only more excessive and severe. Health risks may also be possible from products contaminated with prohibited, unknown ingredients.

If you suspect you're experiencing life-threatening side effects, seek immediate medical attention.

Interactions

There is limited information about safety and possible medication interactions with huperzine A. Most of the data is based on huperzine A's potential uses.

Alzheimer's disease (AD) medications: Huperzine A may work similarly to Aricept, an AD medication. For this reason, huperzine A may have additive effects with AD medications, raising the risk of side effects.

Anticholinergic medications: Acetylcholine (ACH) is a naturally occurring substance in your body. In people with AD, there is a low level of ACH. Taking anticholinergic medications—like Ditropan XL (oxybutynin) for overactive bladder (OAB)—might worsen this problem and work against AD medications. Since huperzine A may improve AD symptoms by increasing ACH, anticholinergic medications might also work against any benefits of huperzine A.

It is essential to carefully read a supplement's ingredients list and nutrition facts panel to learn which ingredients are present and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications. 

How to Store Huperzine A

Since storage instructions may vary for different natural products, carefully read the directions and packaging label. Keep your medications tightly closed and out of the reach and sight of children and pets, ideally locked in a cabinet or closet. Generally, most medicines' optimal storage condition is in a cool and dry place.

Discard after one year or as indicated on the packaging. Avoid putting unused and expired medicines down the drain or in the toilet. Visit the FDA website to learn where and how to discard all unused and expired medicines. You can also find disposal boxes in your area.

Ask a pharmacist or healthcare provider any questions about how to dispose of your medications or supplements.

Similar Supplements

Huperzine A may have potential uses for memory and brain function. Other, similar supplements include:

Vitamins B and E: According to the National Center for Complementary and Integrative Health (NCCIH), people with AD may benefit from vitamin E. For instance, vitamin E might allow people with AD to perform more activities of daily living on their own for a longer period.

Long-term use of specific B vitamins may slow down worsening memory problems in older adults. These B vitamins include pyridoxine (vitamin B6), folic acid (vitamin B9), and cyanocobalamin (vitamin B12).

Omega-3 fatty acids: Based on available data, omega-3 fatty acids from eating more fish may prevent worsening memory problems in older adults.

Don't combine multiple natural products until you first talk with a healthcare provider or pharmacist. Consulting with a provider may help you avoid possible interactions and side effects and ensure you're giving these supplements a fair trial at appropriate doses.

Sources of Huperzine A & What to Look For

Sources of huperzine A may include foods and supplements.

Food Sources of Huperzine A

Huperzine A is naturally found in the herb Chinese club moss, but there is little information about other food sources of huperzine A.

Huperzine A Supplements

Huperzine A is available in several forms, including capsules and tablets. If you have difficulties swallowing pills, huperzine A may also be available in liquid and powder forms.

Vegetarian and vegan options might also be available. You may also see huperzine A in combination with other ingredients.

Your specific product will depend on your preference and what you hope to get in terms of effects. Each product may work a bit differently, depending on the form. So, following a healthcare provider's recommendations or label directions is essential.

Summary

Huperzine A is a substance found in the herb Chinese club moss. It's used in traditional Chinese medicine. It is potentially helpful for brain health, especially in people with Alzheimer's disease or vascular dementia.

Additional higher-quality clinical trials are still necessary to better assess the effectiveness and safety of huperzine A. Before taking huperzine A, consult with a pharmacist or healthcare provider to help you safely achieve your health goals.