What Is Ginkgo Biloba?

Ginkgo biloba, or ginkgo biloba leaf extract, is an herbal supplement extracted from ginkgo biloba tree leaves. Often used in Traditional Chinese medicine (TCM), ginkgo biloba is believed to help improve memory, brain function, and blood flow. It is also called ginkgo, fossil tree, maidenhair tree, baiguo, yinhsing, and Japanese silver apricot.

Ginkgo biloba contains antioxidants that may improve blood flow and age-related memory issues. However, research on the health benefits of ginkgo biloba is limited.

Potential Benefits of Ginkgo Biloba

Ginkgo biloba extract's active ingredients include terpene lactones (terpenoids) and ginkgo flavone glycoside (flavonoids). These compounds have an antioxidant effect that may help prevent tissue damage and disease. In addition, the flavonoids in ginkgo also promote blood flow.

Because of these active ingredients, ginkgo biloba extract supplements may help improve brain function and blood circulation related to blood pressure, memory, and eye health. However, there is not enough information to prove ginkgo biloba improves any health conditions.

Here's what we do know from limited ginkgo biloba studies.

Memory and Cognition

Proponents of ginkgo biloba suggest the supplement can help improve memory and age-related cognitive decline, and the supplement is sometimes used as a natural Alzheimer's disease treatment. A review of 21 clinical trials found combining conventional Alzheimer's treatments and ginkgo biloba helps participants with mild Alzheimer's disease symptoms improve cognitive function. However, more research is needed since the trials included varied in sample size, quality, and results. 

Since evidence is limited, there is also not enough evidence to prove ginkgo biloba can help treat or prevent Alzheimer's disease. Another large meta-analysis found ginkgo biloba did not significantly improve memory, attention, or executive function in healthy adults.

Eye Diseases

Research shows ginkgo biloba's antioxidant properties can help improve blood flow to the eye's optic nerve and retina. Ginkgo may also provide an anti-inflammatory response that helps prevent eye degeneration and related vision issues. A 2019 review concluded these effects might help treat glaucoma. This eye condition damages the optic nerve and can cause vision loss and blindness. However, there's not enough evidence to prove ginkgo can treat vision problems caused by glaucoma. 

Another small review found ginkgo may help slow the progression of age-related macular degeneration—a condition that damages the retina and causes blurry vision. Some participants also experienced improved vision after taking ginkgo. However, the results were mostly insignificant, and we need more extensive studies to prove ginkgo can treat age-related macular degeneration.

Anxiety and Depression 

Limited research has shown taking ginkgo extract may help increase antioxidants to help reduce depression and anxiety symptoms. An older study found taking 480 milligrams of ginkgo biloba extract daily helped reduce anxiety symptoms, compared to the placebo. However, the study only included 107 people with a generalized anxiety disorder and adjustment disorder with anxious mood. We need more quality studies to prove this effect. 

Newer research has also found taking ginkgo biloba with antidepressants helped reduce depression symptoms in older adults with post-stroke depression. However, it is still unclear if ginkgo biloba is an effective treatment for depression, and researchers aren't convinced ginkgo can effectively treat mental health conditions. 

High Blood Pressure

Ginkgo biloba can decrease blood clotting, which may help improve blood flow and lower high blood pressure (aka hypertension). However, studies are extremely small and limited. In a 2014 review, most clinical trials found that ginkgo biloba extract helped reduce that participant's blood pressure. However, some studies found the supplement had no significant effect on blood pressure and included flawed research methods. 

A 2018 study, including people with arterial hypertension, also found ginkgo biloba extract helped reduce blood pressure just as much as basic treatment. However, the study only included 43 participants overall, and more better-quality studies are needed to prove that ginkgo biloba has the same effect.  

How to Take Ginkgo Biloba

Gingko biloba supplements are available in capsules, tablets, and liquid extracts. You may also find dried leaves or ginkgo biloba tea. Most ginkgo supplements are taken one to two times daily with food. Ginkgo seeds and raw leaves are poisonous and should be avoided.

Dosage 

There is no standard dosage for ginkgo biloba. How much you take depends on the formulation and personal factors like age, sex, and medical history. However, research has shown taking 120 to 160 milligrams (mg) two times daily, 40 mg three times daily, or 80 mg twice daily is typically safe.

Before you start taking ginkgo biloba, talk with your healthcare provider. 

Is Ginkgo Biloba Safe?

Ginkgo biloba extract is considered safe for most people in moderate doses. However, ginkgo can increase the risk of bleeding and is unsafe for pregnant people and people with bleeding disorders. There is also no proof that ginkgo is safe to use while breastfeeding, so it is best to avoid it.

During pregnancy, ginkgo biloba may cause early labor and excess bleeding during childbirth. Because of the bleeding risk, the American Society of Anesthesiologists and the American Academy of Orthopedic Surgeons also recommend avoiding ginkgo biloba two weeks before surgery.

Raw and roasted ginkgo seeds and raw ginkgo leaves are poisonous and unsafe to ingest. The seeds especially contain large amounts of ginkgotoxin—a compound that can block vitamin B6 and cause neurotoxic effects like seizures and coma. 

Potential Drug Interactions

Gingko can interact with medications and other herbs that increase bleeding. Combining ginkgo with the following medications and supplements may increase the risk of excess bleeding: 

• Blood thinners like Coumadin (warfarin)
• Nonsteroidal anti-inflammatory drugs (NSAIDs), like Aspirin (acetylsalicylic acid) 
• Antiplatelet agents, like Pletal (cilostazol) 
• Garlic 
• Ginger
• Ginseng 

People taking monoamine oxidase inhibitors (MOAs) to treat depression—like Emsam (selegiline) and Marplan (isocarboxazid)—should also speak with their healthcare provider before taking ginkgo biloba. Ginkgo may act similarly to MOAs and change brain chemical levels. This interaction may cause serotonin syndrome—a dangerous condition that causes excess serotonin in the brain.

What to Look For

You can find ginkgo biloba supplements at health food stores, supplement stores, and drugstores. Ginkgo supplements may also be called baiguo, fossil tree, and yinhsing.

The U.S. Food and Drug Administration does not regulate dietary supplement use claims or ingredients like medications. The quality and doses of ginkgo biloba extracts can vary greatly, with some containing almost no ginkgo biloba. Information from third-party testing organizations can help identify if a product is manufactured correctly, includes the right ingredients, and is free of harmful contaminants. 

To increase your chances of buying a safe and quality product, look for the following information on ginkgo biloba supplement labels:

• Amount of ginkgo biloba extract (from ginkgo biloba leaf)
• Amount of active ingredients like ginkgo flavone glycosides and terpene lactones
• List of additional binders, flavors, and fillers
• Seal of approval from a third-party testing organization like ConsumerLab.com, NSF International, or U.S. Pharmacopeia
  

Can You Take Too Much Ginkgo Biloba?  

You can take too much ginkgo biloba. Taking more than 600 mg may be unsafe. Research has shown that taking more than 240 mg daily may result in unwanted side effects and drug interactions.

Eating ginkgo seeds or leaves can cause ginkgo poisoning. Studies have shown children can overdose on 7 to 150 ginkgo seeds, while adults have overdosed on 40 to 300 seeds. That being said, you should avoid taking any amount of ginkgo seeds. 

Side Effects of Ginkgo Biloba

Ginkgo biloba can lead to side effects even if taken in moderate amounts. Side effects of taking ginkgo supplements can include:

• Headache
• Dizziness
• Upset stomach
• Heart palpitations
• Constipation
• Rash (allergic skin reaction)
• Excess bleeding (if you have an increased risk of bleeding)
  

If you consume raw or roasted ginkgo seeds or raw leaves, you can also experience ginkgo poisoning. Symptoms can vary in severity depending on your age, size, and intake. Gingko poisoning is more common in children who accidentally ingest ginkgo.

Ginkgo poisoning causes a B6 deficiency that leads to symptoms like:

• Vomiting
• Drowsiness
• Seizures
• Unconsciousness 
• Difficulty breathing
• Upset stomach
• Dark purple complexion
• Diarrhea

A Quick Review

Ginkgo biloba extract has antioxidant properties that may help reduce inflammation and improve blood flow. Limited research shows ginkgo biloba may help treat high blood pressure, improve eye health, and improve memory and cognition. However, no solid evidence proves ginkgo biloba can help treat or prevent any health condition. Still, ginkgo biloba extract is generally considered safe if you do not have an increased risk of bleeding or are pregnant.