Overview

Huperzine A is a chemical found in a type of moss known as Chinese clubmoss (Huperzia serrata). It is commonly used for memory problems, including dementia, but its benefits for any use are not well defined. Common side effects include dizziness, constipation, diarrhea, nausea, and vomiting. Huperzine A may interact with many medicines. Before taking huperzine A, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is huperzine A used for?

Huperzine A is commonly used to improve memory and brain health, but its benefits are not well defined.

Note: The FDA has not reviewed huperzine A for safety and effectiveness. Learn more about dietary supplements here.

How does huperzine A work (mechanism of action)?

Huperzine A is a chemical that is naturally found in a type of moss known as Chinese clubmoss (Huperzia serrata). It is not the same as huperzine B, which is one of many other chemicals found in Chinese clubmoss. Huperzine A and huperzine B have different effects in the body.

Huperzine A can block an enzyme called acetylcholinesterase, which breaks down an important brain chemical called acetylcholine. By increasing the levels of acetylcholine, huperzine A may help increase a type of brain communication called cholinergic activity. This is thought to be helpful for improving memory and thinking skills, especially in people with age-related memory problems or dementia. But research on the use of huperzine A is limited, and its benefits are not well defined. It is also not clear how huperzine A compares to prescription medicines that block acetylcholinesterase, such as donepezil and rivastigmine.

How should I store huperzine A?

You should store huperzine A according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of huperzine A?

The most common side effects of huperzine A are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Dizziness
• Constipation or diarrhea
• Nausea or vomiting

There may be other side effects of huperzine A that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of huperzine A?

While less common, the most serious side effects of huperzine A are described below, along with what to do if they happen.

Severe Allergic Reactions. Huperzine A may cause allergic reactions, which can be serious. Stop taking huperzine A and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Precautions

Who should not use huperzine A?

Allergies to Ingredients. People who are allergic to any of the following should not take huperzine A.

• Huperzine A
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific huperzine A products they stock.

What should I know about huperzine A before using it?

Huperzine A is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep huperzine A out of the reach of children.

Many dietary supplements that contain huperzine A are made from Chinese clubmoss (Huperzia serrata). Chinese clubmoss contains many other chemicals that can have effects in the body. Read the product label carefully to confirm whether it contains Chinese clubmoss or any other ingredients.

People who are 65 years or older can be at greater risk for some side effects from huperzine A. Talk to your health care provider about your risks if you are in this age group.

The FDA has not tested huperzine A products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using huperzine A?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if huperzine A is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Asthma
• Heart problems, including changes in your blood pressure or heart rate
• Parkinson’s disease
• Problems emptying your bladder
• Stomach ulcers or other stomach problems
• Dementia or Alzheimer’s disease

Other Medicines and Supplements.Huperzine A may interact with other medicines and supplements. Before taking huperzine A, tell your health care provider about any prescription or OTC medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how huperzine A could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if huperzine A passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does huperzine A interact with foods or drinks?

There are no known interactions between huperzine A and foods or drinks.

It is unknown if drinking alcohol will affect huperzine A.

Does huperzine A interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking huperzine A.

• A type of medicine called a cholinergic, such as bethanechol, carbachol (Miostat), or pilocarpine (Salagen and others), which may be used if you are unable to empty your bladder (urinary retention) or have dry mouth, dry eyes, or glaucoma
• An anticholinergic medicine, which includes antihistamines and medicines commonly used for overactive bladder, Parkinson’s disease, or stomach problems
• An acetylcholinesterase inhibitor, such as donepezil (Aricept), galantamine, or rivastigmine (Exelon), which is a medicine commonly used for dementia
• A beta-blocker, such as atenolol (Tenormin), metoprolol (Lopressor, Toprol XL, and others), or propranolol (Inderal LA, InnoPran XL), which is a medicine that may be used for certain heart conditions or to lower blood pressure
• A calcium channel blocker, such as diltiazem (Cardizem CD and others) or verapamil (Verelan, Verelan PM), which is a medicine used for high blood pressure or other conditions
• Scopolamine (Transderm Scop), which is a patch used to reduce nausea or vomiting from motion sickness or surgery

The interactions between huperzine A and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with huperzine A is incomplete. Always check with your health care provider before taking huperzine A with any medicines.

Dosing

What should I do if I accidentally use too much huperzine A?

If you or someone else has used too much huperzine A, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Read the product label closely, and speak with a health care provider about how to take huperzine A safely. Do not take double or extra doses, even if you miss a dose.