Ginkgo - Side Effects

Parts Used & Where Grown

Ginkgo biloba is the world’s oldest living species of tree. Individual trees live as long as 1,000 years. Ginkgo grows most predominantly in the southern and eastern United States, southern France, China, and Korea. The leaves of the tree are used in modern herbal medicine.

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This supplement has been used in connection with the following health conditions:

Used for	Amount	Why
Age-Related Cognitive Decline	120 to 160 daily	Most, but not all, clinical trials have found this herb to be a safe and effective treatment for ARCD.
Age-Related Cognitive Decline 120 to 160 daily Most¹ ^{, 2} ^{, 3} ^{, 4} ^{, 5} ^{, 6} ^{, 7} but not all⁸ clinical trials, many of them double-blind, have found ginkgo supplementation to be a safe and effective treatment for ARCD. Learn More

Used for	Amount	Why
Alzheimer’s Disease	120 to 240 mg of a standardized herbal extract daily	Ginkgo biloba extract is an approved treatment for early-stage Alzheimer’s disease in Europe. It is thought to improve memory and quality of life and slow early disease progression.
Alzheimer’s Disease 120 to 240 mg of a standardized herbal extract daily An extract made from the leaves of the Ginkgo biloba tree is an approved treatment for early-stage Alzheimer’s disease in Europe. While not a cure, Ginkgo biloba extract may improve memory and quality of life and slow progression in the early stages of the disease. In addition, four double-blind trials have shown that ginkgo is helpful for people in early stages of Alzheimer’s disease, as well as for those experiencing another form of dementia known as multi-infarct dementia.⁹ ^{, 10} ^{, 11} ^{, 12} Ginkgo has been found to be nearly as effective against Alzheimer's disease as donepezil, a prescription drug used to treat the condition.¹³ One trial reported no effect of ginkgo supplementation in the treatment of Alzheimer’s disease, vascular dementia or age-associated memory impairment.¹⁴ However, the results of this trial have been criticized, since analysis of the results does not separate those patients with Alzheimer’s disease or vascular dementia from those with age-associated memory impairment. A comparison of placebo-controlled trials of ginkgo for Alzheimer’s disease concluded that the herb compared favorably with two prescription drugs, donepezil and tacrine, commonly used to treat the condition.¹⁵ Research studies have used 120 to 240 mg of ginkgo, standardized to contain 6% terpene lactones and 24% flavone glycosides per day, generally divided into two or three portions. Ginkgo may need to be taken for six to eight weeks before desired actions are noticed. Ginkgo was not effective for preventing Alzheimer's disease in elderly volunteers with normal cognitive function or in those with mild cognitive impairment.¹⁶ Learn More

Used for	Amount	Why
Glaucoma	120 mg daily of a standardized herbal extract	In cases of normal tension glaucoma; ginkgo may help improve vision.
Glaucoma 120 mg daily of a standardized herbal extract In a double-blind study, supplementation with a standardized extract of Ginkgo biloba in the amount of 40 mg three times a day for four weeks partially reversed visual field damage in people with one type of glaucoma (normal tension glaucoma).¹⁷ Learn More

Used for	Amount	Why
Intermittent Claudication	120 to 160 mg daily	Studies have reported that people with intermittent claudication see improvements in pain-free walking distance when supplementing with ginkgo.
Intermittent Claudication 120 to 160 mg daily Extensive studies have been done with Ginkgo biloba extracts (GBE) for treatment of intermittent claudication.¹⁸ ^{, 19} Two double-blind trials found that 120 mg of GBE per day increased pain-free and total walking distance among people with intermittent claudication.²⁰ ^{, 21}Similar results were seen in another double-blind trial using 160 mg of GBE per day.²² In yet another double-blind trial, two doses of ginkgo extract were compared for six months.²³ The researchers studied 60 vs. 120 mg twice daily and found that, while both amounts resulted in significant improvements in pain-free walking distance, the improvements were more pronounced at the higher dose. One double-blind study found that ginkgo extract was not beneficial.²⁴ However, that study lasted only three months, whereas the positive studies lasted six months. It may take longer than three months for ginkgo to have a beneficial effect in people with intermittent claudication. Learn More

Used for	Amount	Why
Depression	240 mg daily	Ginkgo may alleviate depression in elderly people not responding to antidepressant drugs.
Depression 240 mg daily Ginkgo biloba (240 mg per day) may alleviate depression in depressed elderly people not responding to antidepressant drugs.²⁵ It is unknown if ginkgo could alleviate depression in other age groups. A small, preliminary trial has shown that ginkgo can reduce sexual problems caused by antidepressants like fluoxetine (Prozac), bupropion (Wellbutrin), venlafaxine (Effexor), and nefazodone (Serzone) in men and women.²⁶ Double-blind trials are now needed to determine whether ginkgo is truly effective for this purpose. Learn More

Used for	Amount	Why
Erectile Dysfunction	60 to 240 mg daily	The herb Ginkgo appears to increase blood flow to the penis.
Erectile Dysfunction 60 to 240 mg daily Ginkgo biloba may help some men with ED by increasing blood flow to the penis. One double-blind trial found improvement in men taking 240 mg per day of a standardized Ginkgo biloba extract (GBE) for nine months.²⁷ A preliminary trial, involving 30 men who were experiencing ED as a result of medication use (selective serotonin reuptake inhibitors and other medications), found that approximately 200 mg per day of GBE had a positive effect on sexual function in 76% of the men.²⁸ Learn More

Used for	Amount	Why
Macular Degeneration	120 to 240 mg daily of a standardized herbal extract	Taking ginkgo may help treat early stage macular degeneration.
Macular Degeneration 120 to 240 mg daily of a standardized herbal extract Ginkgo(Ginkgo biloba) may help treat early-stage macular degeneration, according to small, preliminary clinical trials.²⁹ Many healthcare professionals recommend 120 to 240 mg of standardized extract (24% ginkgo flavone glycosides and 6% terpene lactones) in capsules or tablets per day. Learn More

Used for	Amount	Why
Schizophrenia (Haloperidol)	360 mg daily of a standardized extract	In one trial, schizophrenic patients who supplemented with ginkgo saw enhanced effectiveness of the antipsychotic drug haloperidol (Haldol) and reduced drug side effects. Learn More
Vertigo	120 to 160 mg a day of a standardized herbal extract	Taking ginkgo may help reduce symptoms.
Vertigo 120 to 160 mg a day of a standardized herbal extract In a preliminary clinical trial, a standardized extract of Ginkgo biloba (GBE) significantly reduced symptoms of vertigo in a group of elderly people with mild cognitive impairment.³⁰ Participants were given 40 mg three times per day for one year. GBE has also been reported to significantly reduce vertigo of unknown cause in preliminary³¹ and double-blind³² trials. The amounts given were 120 mg and 160 mg per day, respectively, for three months. Learn More

Used for	Amount	Why
Vitiligo	120 mg daily of a standardized extract	Taking ginkgo may help improve repigmentation of skin.
Vitiligo 120 mg daily of a standardized extract In a double-blind study of 52 people with slowly spreading vitiligo, supplementation with Ginkgo biloba extract (standardized to contain 24% ginkgoflavonglycosides), in the amount of 40 mg three times per day for up to six months, resulted in marked to complete repigmentation in 40% of cases, compared with only 9% among those receiving a placebo.³³ Learn More

Used for	Amount	Why
Asthma	Refer to label instructions	Supplementing with the herb Ginkgo biloba may improve asthma, as its extracts block the action of a compound that contributes to asthma symptoms.
Asthma Ginkgo biloba extracts have been considered a potential therapy for asthma. This is because the extracts block the action of platelet-activating factor (PAF), a compound the body produces that in part causes asthma symptoms. A trial using isolated ginkgolides from ginkgo (not the whole extract) found they reduced asthma symptoms.³⁴ A controlled trial used a highly concentrated tincture of ginkgo leaf and found this preparation helped decrease asthma symptoms.³⁵ For asthma, 120 to 240 mg of standardized ginkgo or 3 to 4 ml of regular tincture three times daily can be used. Learn More

Used for	Amount	Why
Atherosclerosis	Refer to label instructions	The herb Ginkgo biloba may reduce atherosclerosis risk by stopping platelets from sticking together too much. It also increases blood circulation to the brain, arms, and legs.
Atherosclerosis Ginkgo may reduce the risk of atherosclerosis by interfering with a chemical the body sometimes makes in excess, called platelet activating factor (PAF).³⁶ PAF stimulates platelets to stick together too much; ginkgo stops this from happening. Ginkgo also increases blood circulation to the brain, arms, and legs.³⁷ Garlic and ginkgo also decrease excessive blood coagulation. Both have been shown in double-blind³⁸ and other controlled³⁹ trials to decrease the overactive coagulation of blood that may contribute to atherosclerosis. Numerous medicinal plants and plant compounds have demonstrated an ability to protect LDL cholesterol from being damaged by free radicals. Garlic,⁴⁰ ginkgo,⁴¹ and guggul⁴² are of particular note in this regard. Garlic and ginkgo have been most convincingly shown to protect LDL cholesterol in humans. Learn More

Used for	Amount	Why
Ménière’s Disease	Refer to label instructions	Ginkgo has been reported to reduce symptoms of tinnitus, vertigo, and hearing loss due to unspecified inner ear disorders.
Ménière’s Disease Although Ginkgo biloba extract (GBE) has not been studied specifically for its effects in MD, in preliminary studies it has been reported to reduce symptoms of tinnitus, vertigo, and hearing loss due to unspecified inner ear disorders.⁴³ Controlled research using GBE is needed to determine whether it is a treatment option specifically for MD. Learn More

Used for	Amount	Why
Migraine Headache	Refer to label instructions	Ginkgo extract may also help because it inhibits the action of a substance known as platelet-activating factor, which may contribute to migraines.
Migraine Headache Ginkgo biloba extract may also help because it inhibits the action of a substance known as platelet-activating factor,⁴⁴ which may contribute to migraines. No clinical trials have examined its effectiveness in treating migraines, however. Learn More

Used for	Amount	Why
Multiple Sclerosis	Refer to label instructions	Inflammation of nerve tissue is partly responsible for the breakdown of myelin in people with MS. In one study, people with MS showed improvement after being given injections of a constituent of ginkgo.
Multiple Sclerosis Inflammation of nerve tissue is partly responsible for the breakdown of myelin in people with MS. When intravenous injections of a constituent of Ginkgo biloba, known as ginkgolide B, were given to people with MS for five days, 80% of them reportedly improved.⁴⁵ This specialized treatment is experimental, and it is not known whether oral use of ginkgo extracts would have a similar effect. Learn More

Used for	Amount	Why
Premenstrual Syndrome	Refer to label instructions	Standardized herbal Ginkgo extract has been shown to alleviate PMS symptoms.
Premenstrual Syndrome A double-blind trial has shown that standardized Ginkgo biloba extract, when taken daily from day 16 of one menstrual cycle to day 5 of the next menstrual cycle, alleviates congestive and psychological symptoms of PMS better than placebo.⁴⁶ The trial used 80 mg of a ginkgo extract two times per day. Learn More

Used for	Amount	Why
Raynaud’s Disease	Refer to label instructions	The herb Ginkgo has been reported to improve the circulation in small blood vessels and reduce pain in people with Raynaud’s disease.
Raynaud’s Disease Ginkgo biloba has been reported to improve the circulation in small blood vessels.⁴⁷ For that reason, some doctors recommend ginkgo for people with Raynaud’s disease. One preliminary trial found that 160 mg of standardized ginkgo extract per day reduced pain in people with Raynaud’s disease.⁴⁸ Larger clinical trials are needed to confirm ginkgo’s effectiveness for this condition. Ginkgo is often used as a standardized extract (containing 24% ginkgo flavone glycosides and 6% terpene lactones). Doctors who recommend use of ginkgo often suggest that people take 120–160 mg per day. Learn More

Used for	Amount	Why
Retinopathy	Refer to label instructions	Using a standardized extract of ginkgo has been reported to improve visual function in people with mild diabetic retinopathy.
Retinopathy The use of 160 mg per day of a standardized extract of Ginkgo biloba for six months has been reported in a small double-blind trial⁴⁹ to improve impaired visual function in people with mild diabetic retinopathy. Learn More

Used for	Amount	Why
Tinnitus	Refer to label instructions	The herb ginkgo may be useful in treating tinnitus.
Tinnitus Ginkgo biloba has been used to treat tinnitus, with mixed results.⁵⁰ The largest placebo-controlled trial to date failed to find any effect of 150 mg per day of ginkgo extract in people with tinnitus.⁵¹ Two smaller, controlled trials have found that standardized ginkgo extract (120 mg per day, containing 24% flavone glycosides and 6% terpene lactones), was effective at relieving the symptoms of tinnitus.⁵²^{, 53} One trial failed to find ginkgo beneficial, but used less than 30 mg of ginkgo extract per day, an amount unlikely to have any therapeutic effect.⁵⁴ Learn More

Used for	Amount	Why
Type 1 Diabetes	Refer to label instructions	The herb ginkgo may help prevent and treat early-stage diabetic nerve damage.
Type 1 Diabetes Ginkgo biloba extract may prove useful for prevention and treatment of early-stage diabetic nerve damage (neuropathy), though research is at best very preliminary in this area.⁵⁵ Learn More

Used for	Amount	Why
Type 2 Diabetes	Refer to label instructions	Ginkgo may help prevent and treat early-stage diabetic neuropathy.
Type 2 Diabetes Ginkgo biloba extract may prove useful for prevention and treatment of early-stage diabetic neuropathy, though research is at best very preliminary in this area.⁵⁶ Learn More

Traditional Use (May Not Be Supported by Scientific Studies)

Medicinal use of ginkgo can be traced back almost 5,000 years in Chinese herbal medicine. The nuts of the tree were most commonly recommended and used to treat respiratory tract ailments. The use of the leaves is a modern development originating in Europe.

Also indexed as:

botanicals,
ginkgo,
ginkgo biloba,
herbal dietary supplements,
herbal medicine,
herbal remedies,
herbal therapy,
herbalism,
plant Medicine

About this treatment

Common names:

Maidenhair Tree

Botanical names:

Ginkgo biloba

Side Effects

Excessive bleeding has been reported in a few individuals taking ginkgo, although a cause/effect relationship was not proven. In addition, two elderly individuals with well-controlled epilepsy developed recurrent seizures within two weeks after starting ginkgo. Mild headaches lasting for a day or two and mild upset stomach have been reported in a small number of people using ginkgo.

Ginkgo leaves are known to contain a group of potentially toxic constituents known as alkylphenols. To reduce the potential for adverse effects, the German Commission E Monograph requires that ginkgo products for human consumption contain less than 5 parts per million of alkylphenols.

One small clinical trial found that ginkgo supplementation for three months increased secretion of insulin by the pancreas, but did not affect blood glucose levels, in healthy young adults. These results suggest that the participants may have developed an insensitivity to insulin, a potential concern because insulin insensitivity may be a precursor to type 2 diabetes. However, this trial does not prove that ginkgo causes insulin insensitivity, nor does it prove that long-term ginkgo supplementation increases the risk for any disease. In addition, the results of this trial are not consistent with other research on ginkgo. Larger and more rigorously designed clinical trials of ginkgo supplementation have found no significant adverse effects after as many as 12 months of supplementation.

People should seek an accurate medical diagnosis prior to self-prescribing ginkgo. This is especially important for the elderly, whose circulatory conditions can involve serious disease, and for people scheduled for surgery, as ginkgo may affect bleeding time.

References

Last Review: 05-11-2011

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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2011.

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