Ginkgo Biloba: Benefits, Side Effects, Dosage, and Interactions

Ginkgo biloba is an antioxidant-rich herb used to enhance brain health and treat a variety of conditions. Although dietary supplements typically contain extracts of the plant's leaves, ginkgo biloba seeds are commonly used for healing purposes in traditional Chinese medicine. Proponents suggest that ginkgo biloba can protect against aging-related issues such as dementia by improving blood flow to the brain.

Health Benefits

Ginkgo biloba is said to aid in the treatment or prevention of the following health problems:

In addition, ginkgo biloba is said to preserve memory, as well as promote recovery from stroke.

Scientific studies support some, but not all ginkgo benefits. Here's a look at the science behind the potential health benefits of ginkgo biloba:

Brain Health

So far, studies testing ginkgo biloba's effects against aging-related declines in brain health have yielded mixed results.

In a research review published in the Journal of Alzheimer's Disease in 2015, for instance, scientists analyzed nine previously published clinical trials focusing on ginkgo biloba's possible role in the treatment of cognitive impairment and dementia. All of the trials focused on a ginkgo biloba extract called EGb761.

In their conclusion, the review's authors state that taking 240 mg of EGb761 per day for at least 22 weeks may stabilize or slow decline in cognition, function, and behavior in patients with cognitive impairment or dementia.

However, an earlier report (published in the Cochrane Database of Systematic Reviews in 2009) concluded that evidence for ginkgo biloba's effects against dementia and cognitive impairment is "inconsistent and unreliable." In their review of 36 clinical trials assessing ginkgo biloba's efficacy and safety as a treatment for dementia or cognitive decline, the report's authors found that the herb appears to be safer than placebo but that most of the reviewed studies were significantly flawed.

Eye Health

Ginkgo biloba shows promise in the treatment of glaucoma, suggests a small study published in the Journal of Glaucoma in 2013. In tests on 42 patients, researchers determined that treatment with ginkgo biloba extract may help slow the progression of glaucoma-related damage to the visual field.

What's more, a report published in the Cochrane Database of Systematic Reviews in 2013 found some evidence that ginkgo biloba may be of possible benefit in the treatment of age-related macular degeneration.

Blood Pressure

It's too soon to tell whether ginkgo biloba can help treat high blood pressure, according to a research review published in Phytomedicine in 2014. Although six of the nine reviewed clinical trials found that gingko biloba may help reduce blood pressure, the herb did not appear to have significant effects on blood pressure in the other three trials.

Since most of the reviewed studies were considerably flawed, the review's authors state that more rigorous research is needed before ginkgo biloba can be recommended for blood pressure control.

Stroke Recovery

Ginkgo biloba might not be beneficial to individuals recovering from a stroke, according to a report published in the Cochrane Database of Systematic Reviews in 2005. In their analysis of 10 clinical trials, the report's authors found no convincing evidence that ginkgo biloba can improve neurological function in patients who have experienced an acute ischemic stroke (the most common stroke type).

Possible Side Effects

Ginkgo biloba may trigger the following side effects: allergic skin reactions, diarrhea, digestive problems, dizziness, headaches, muscle weakness, and nausea.

Since ginkgo biloba may affect blood clotting, it shouldn't be used by people with bleeding disorders or those who are taking medication or supplements that affect blood clotting, such as warfarin, aspirin, garlic and vitamin E. Individuals with epilepsy or diabetes should also avoid use of ginkgo biloba, unless the herb is taken under the supervision of a medical professional. Pregnant women shouldn't take ginkgo.

Given the number of medications and supplements that may interact with ginkgo, it's a good idea to consult your primary care provider before taking ginkgo.

Ginkgo contains a compound called ginkgotoxin. Although ginkgotoxin is found in the largest amounts in ginkgo nuts, it's also present in small quantities in the leaves. Structurally similar to vitamin B6, it has been found to block vitamin B6 activity. According to one case report, a woman developed generalized tonic-clonic seizure after eating large amounts of ginkgo nuts and had lowered blood vitamin B6 levels. (After treatment, which included vitamin B6 medication, her symptoms resolved and no seizures recurred).

Dosage and Preparation

There is no established standard dose for gingko biloba. Different formulations and doses have been used in research studies investigating the herb's effect on various conditions. The right dose for you may depend on several factors, including your age, gender, medical history, and formulation used.

The Natural Medicine Database advises that consumers start taking the supplement at a lower dose (not more than 120 mg per day) to avoid side effects. From there, you may be able to increase to a higher dose as needed.

As always, speak with your healthcare provider to get personalized advice regarding the right dose for you.

What to Look For

Gingko is known by many other names, including bai guo ye, yinhsing, and fossil tree. But the supplement is popularly known as gingko biloba and you will most likely see it on store shelves labeled as such. Almost all health food markets and vitamin shops sell this product.

To make sure that you get the proper dose, the National Institutes of Health (NIH) recommends that you look for a Supplement Facts label on the product that you buy. This label will contain vital information including the amount of active ingredients per serving. You can also find out if other ingredients have been added to the product such as fillers, binders, and flavorings.

Lastly, the organization suggests that you look for a product that contains a seal of approval from a third party organization that provides quality testing. These organizations include U.S. Pharmacopeia, ConsumerLab.com, and NSF International. A seal of approval from one of these organizations does not guarantee the product's safety or effectiveness but it does provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.