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15 Ginkgo Biloba Benefits & Side Effects

Written by Carlos Tello, PhD (Molecular Biology) | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Carlos Tello, PhD (Molecular Biology) | Last updated:

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Ginkgo Biloba

Ginkgo biloba is one of the oldest living tree species. Extracts of this plant can have positive effects on cognition, memory, blood flow, mood, and oxidative stress. Continue to read to know more about the other potential health benefits of ginkgo.

What Is Ginkgo Biloba?

Ginkgo biloba, known as gingko or maidenhair tree, is the only living species of the division Ginkgophyta, all the other members of which have gone extinct. For this reason, it has been referred to as a “living fossil”. Native to China, its seeds have been used in traditional medicine for thousands of years and occasionally eaten when cooked [1].

Ginkgo leaf extract has historically been used to treat a variety of ailments and conditions including asthma, bronchitis, and fatigue. Ginkgo extracts are also used in skin products [1].

EGb 761 is a standardized extract of Ginkgo biloba leaves with antioxidant properties as a free radical scavenger. It was developed by Dr. Willmar Schwabe Pharmaceuticals and has been available in Europe as a herbal extract since the early 1990s [2].

In Norway, ginkgo leaf extract products are approved by the Norwegian Medicines Agency to improve blood circulation [3].

Snapshot

Proponents

  • Antioxidant
  • May improve cognitive function and reduce cognitive decline
  • May improve blood flow and prevent blood clots
  • May help with anxiety, depression, and schizophrenia
  • May help with eye and hearing problems
  • May improve skin appearance
  • May help with diabetes and its complications

Skeptics

  • Insufficient evidence for several benefits
  • May cause bleeding and interact with anticoagulant and anti-platelet medication
  • Not safe for pregnant and breastfeeding women
  • Nuts and seeds are toxic

Health Benefits

Possibly Effective for:

1) Brain Function

Healthy People

In 4 trials on over 200 healthy young volunteers, ginkgo extract improved sustained attention (but not speed of attention), pattern recognition, and performance in subtraction tasks. However, only its acute administration was effective, suggesting that the participants developed tolerance [4, 5, 6, 7].

Ginkgo biloba extract (EGb 761) improved memory and executive function in 5 clinical trials on over 500 healthy, middle-aged volunteers [8, 9, 10, 11, 12].

In 3 trials on over 300 cognitively intact elderly people, ginkgo extract improved delayed free recall, recognition memory, speed of information processing, and overall cognitive functioning [13, 14, 15].

However, ginkgo extract had no effect on learning, memory, attention, concentration, and verbal fluency in 2 other trials on over 200 elderly people without cognitive impairment [16, 17].

People with Cognitive Impairment

In 3 clinical trials on over 100 people with mild cognitive impairment, ginkgo extract improved cognitive flexibility, response inhibition, dual-task gait performance, and general cognitive performance [18, 19, 20].

In clinical trials on 820 people with Alzheimer’s or other types of dementia (e.g., vascular), Ginkgo biloba extract improved cognitive function, neuropsychiatric symptoms, and functional abilities [21, 22, 23, 24]

However, it was ineffective in 2 trials on over 400 elderly people with dementia and age-associated memory impairment [25, 26].

A meta-analysis of 13 studies and over 2,300 people concluded that a 240-mg daily dose of ginkgo extract was safe and effective in the treatment of dementia [27].

In any case, ginkgo extract seems ineffective at preventing Alzheimer’s or dementia based on the results of 3 studies on over 6,000 people [28, 29, 30].

In rats and mice, Ginkgo biloba extract improved cognitive impairment due to aging, reduced oxygen supply to the brain, repeated stimulation of glutamate receptors, and fluoride and aluminum poisoning [31, 32, 33, 34].

Additionally, EGb 761 extract reduced the damage to midbrain dopamine brain cells in animal models of Parkinson’s disease [35].

Taken together, the evidence suggests that ginkgo extract may help enhance cognitive function in healthy people and reduce cognitive impairment symptoms in people with conditions such as Alzheimer’s or other types of dementia. You may discuss with your doctor if you may use this supplement as a cognitive enhancer or give it to your loved ones with cognitive impairment.

2) Blood Flow

In a small trial on 16 healthy volunteers, Gingko biloba extract increased circulation in the forearm without changing overall blood pressure levels. In another trial on 70 healthy volunteers, EGb 761 extract prevented the rise of blood pressure caused by stress [36, 37].

Ginkgo extract also increased microcirculation in the skin and liver in a clinical trial on 32 elderly people [38].

In a clinical trial on 80 people with coronary artery disease, ginkgo extract improved coronary blood flow. The extract was similarly effective in another trial on 60 healthy elderly people [39, 40].

Similarly, ginkgo extract improved blood flow to the brain, thus reducing the risk of stroke, in a clinical trial on 60 people with poor blood flow due to surgery [41].

It also increased blood flow in the eyes in 3 clinical trials on 86 people, suggesting its potential to help with conditions such as glaucoma [42, 43, 44].

Ginkgo biloba improved blood flow and walking distance in 2 clinical trials on over 100 people with peripheral arterial insufficiency. However, ginkgo extract was ineffective in another trial on 22 people with this condition [45, 46, 47].

In a clinical trial on 24 people with clogged arteries, Ginkgo biloba along with parenteral therapy decreased collagen-induced blood clotting [48].

In another trial on 66 chronic peritoneal dialysis patients, Ginkgo biloba reversed the blood clotting profile without increasing the risk of bleeding [49].

Ginkgo biloba extract prevented platelets from clumping together in both platelet-rich and whole blood [50].

However, EGb 761 extract had no effect on blood clotting in 2 clinical trials on 82 healthy people [51, 52].

All in all, the evidence suggests that ginkgo extract may improve blood flow and reduce blood clotting. You may use it as an add-on to your treatment regime if your doctor determines that it may be helpful in your case. Importantly, never take ginkgo extract in place of what your doctor recommends or prescribes.

3) Schizophrenia

In a clinical trial on over 150 schizophrenic patients, the antioxidant activity of the Ginkgo biloba extract EGb 761 reduced involuntary movements (tardive dyskinesia). A study on almost 1,500 people associated a genetic polymorphism of BDNF with better improvement of this symptom [53, 54].

Also through its antioxidant activity, ginkgo extract enhanced the effectiveness of antipsychotic drugs such as haloperidol, olanzapine, and clozapine in 5 clinical trials on almost 300 people [55, 56, 57, 58, 59].

A meta-analysis of 8 clinical trials and over 1,000 people concluded that ginkgo extract may improve the symptoms of schizophrenia, especially as an add-on to conventional therapy [60].

The evidence suggests that ginkgo extract may hep with schizophrenic symptoms such as involuntary movements and psychosis, especially when taken in combination with conventional drugs. Discuss with your doctor if it may be helpful in your case and always follow their recommendations carefully.

4) Anxiety and Depression

A standardized extract of Ginkgo biloba (EGb 761) reduced salivary cortisol and blood pressure response to stress in a clinical trial on 70 young, healthy volunteers [61].

EGb 761 was also effective in treating elderly patients with anxiety disorders in a clinical trial on 170 people [62].

EGb 761 reduced anxiety, irritability, and depression in 2 clinical trials on 560 people with cognitive impairment (dementia and mild cognitive impairment) [63, 64].

This extract also reduced the anxiety caused by ringing or buzzing in the ears (tinnitus) in 2 clinical trials on over 200 people [65, 66].

In rats, several compounds isolated from Ginkgo biloba (such as ginkgolic acid conjugates and ginkgolide-A) exhibited an anti-anxiety activity [67, 68].

Ginkgo biloba extract (LI 1370) improved mood and self-assessed task-performance in a large study on over 1,500 older volunteers. In turn, EGb 761 combined with an antidepressant drug (citalopram) improved mood and prevented brain damage better than the drug alone in another trial on 136 elderly people with depression [69, 70].

However, another extract (PN246) failed to prevent winter depression in a clinical trial on 27 people prone to this condition [71].

In a clinical trial on 60 people with poor blood flow to the brain (cerebral insufficiency), ginkgo extract improved depressive mood [72].

Taken together, the evidence suggests that Ginkgo biloba may help with some types of anxiety and depressive disorders. Discuss with your doctor if it may be recommended to add ginkgo to your treatment regime.

5) Antioxidant

Ginkgo biloba contains over 60 active compounds, the most important ones being antioxidant flavonoids such as quercetin and kaempferol. These compounds can be detected in urine after taking ginkgo extract [73, 74].

In a small trial on 18 young, physically active men, supplementing with a commercial ginkgo extract (Ginkoflav) for 6 weeks improved their antioxidant status after strenuous physical exercise [75].

Ginkgo biloba extract EGb 761 taken before heart bypass surgery reduced oxidative damage during the procedure and slightly improved the clinical outcome in another trial on 15 people [76].

Another ginkgo extract improved free radical scavenging capacity and capillary blood flow in a trial on 32 elderly people. Similarly, an antioxidant dietary supplement with Ginkgo biloba reduced oxidative damage to the blood vessels, resulting in an improved blood flow in the retinas, in a clinical trial on 45 people with glaucoma [77, 44].

In 4 clinical trials on over 200 schizophrenic patients, adding gingko extract to their antipsychotic medication enhanced the effectiveness of the treatment and increased the activity of several antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) [55, 56, 57, 58].

In rats, Ginkgo biloba extract EGb 761 improved the activity of antioxidant enzymes and reduced oxidative damage to the brain and retinas [78, 79, 80]

This extract also prevented hydrogen peroxide-induced cellular damage of red blood cells deficient in G6PD (glucose-6-phosphate dehydrogenase) with similar results to vitamin E [81].

All in all, the evidence shows that ginkgo extract contains many antioxidant compounds that may reduce oxidative damage in several cases. You may take this supplement to reduce oxidative damage if your doctor determines that it may help as a complementary approach.

6) Eye Health

In a clinical trial on 11 healthy volunteers, repeated intake of Ginkgo biloba extract increased blood flow in the eyes. This could improve glaucoma by increasing blood supply to the nerves [82, 83].

Indeed, ginkgo extract improved vision and blood flow in 3 trials on 102 people with glaucoma. However, it was ineffective in another trial on 35 people with this condition [84, 43, 44, 85].

In rats with chronic glaucoma, EGb 761 protected the eye nerves from cell death [86].

This extract was also effective for age-related blindness (dry macular degeneration) in a clinical trial on almost 100 people [87].

In a small trial on 15 diabetic children and adolescents, EGb 761 preserved color vision and helped prevent eye nerve damage (diabetic retinopathy) [88].

Alternatively, Ginkgo biloba eye drops improved the symptoms of seasonal allergic conjunctivitis in a clinical trial on 60 people [89].

Although a bit limited, the evidence suggests that ginkgo extract may help with several eye conditions, especially glaucoma. Discuss with your doctor if it may help when added to your medication and never take this supplement in place of what your doctor recommends or prescribes.

7) Skin Appearance

An herbal anti-wrinkle cosmetic formulated from Ginkgo biloba, rooibos, and soybean increased skin moisturization and smoothness while reducing roughness and wrinkles in a clinical trial on 20 women [90].

Similarly, an antioxidant cosmetic formulation with ginkgo extract, Porphyra, and vitamins A, C, and E applied for 90 days improved skin barrier function and moisturization, leading to reduced roughness and wrinkles, in a clinical trial on 45 volunteers [91].

Ginkgo biloba and green tea worked synergistically to improve skin moisturization, elasticity, and barrier function in another trial on 48 healthy volunteers [92].

Ginkgo extract also improved skin pigmentation in 2 clinical trials on 64 people with vitiligo [93, 94].

Again, the evidence is limited but suggests that Ginkgo biloba may help improve the appearance of the skin by delaying its aging and improving vitiligo. You may discuss this potential use with your doctor.

8) Diabetes and Diabetic Complications

In a clinical trial on over 100 people with type 2 diabetes, ginkgo extract improved glycemic control and psychological state. The extract also improved the effectiveness of the antidiabetic drug metformin in another trial on 60 people with this condition [95, 96].

A study on 12 people found that ginkgo extract increased the activity of the pancreatic cells that produce insulin (beta cells). However, this increased insulin production didn’t lead to insulin resistance in another trial on 18 prediabetic and diabetic people [97, 98].

In a pilot trial on 11 people with metabolic syndrome, the EGb 761 extract reduced insulin resistance, two markers of inflammation (CRP and IL-6), and the risk of mortality [99].

The extract may also help with diabetic complications. In a clinical trial on 140 people with type 2 diabetes, the combination of ginkgo leaf tablets with another herbal remedy (Liuwei Dihuang pills) reduced oxidative damage, possibly preventing clogged arteries and other blood vessel complications. Similarly, ginkgo extract reduced a marker of oxidative damage (MDA) in the platelets of 19 people with this condition [100, 101].

In 2 clinical trials on 124 diabetics with kidney damage (diabetic nephropathy), it improved kidney and blood vessel function. Similarly, the extract improved eye damage (diabetic retinopathy) in a small trial on 15 diabetic children and adolescents [102, 103, 88].

In diabetic rats, ginkgo extract reduced blood sugar, blood fats, and oxidative damage, as well as preventing heart damage due to reduced oxygen supply (ischemic injury). In obese rats, it lowered blood sugar and fat levels and improved insulin sensitivity [104, 105, 106].

Again, the evidence is limited but suggests that ginkgo extract may help with both diabetes and its complications. You may take it as an add-on to your anti-diabetic medication if your doctor determines that it may help in your case.

Insufficient Evidence for:

1) Hearing Disorders

EGb 761 extract improved sudden hearing loss and deafness in 3 clinical trials on almost 250 people, with higher doses being more effective [107, 108, 109].

The results of the studies testing ginkgo extract for tinnitus are mixed. While 4 studies on over 300 people found it improved this condition (one found it comparable to the drug pentoxifylline), 4 studies on over 1,000 people found it ineffective [110, 111, 65, 66, 112, 113, 114, 115].

The EGb 761 extract also improved the behavioral symptoms of tinnitus in rats [116].

In animal studies, Ginkgo biloba extract also protected the ears from the toxic effects of the antibiotic gentamicin and the anticancer drug cisplatin [117, 118].

Although the results are promising, the evidence is insufficient to support the use of ginkgo extract in hearing disorders. More clinical research is needed to shed some light on this potential benefit.

2) Fatigue

The standardized extract EGb 761 reduced fatigue and other multiple sclerosis symptoms in a small trial on 22 people with this condition. The extract also reduced fatigue in another trial on 66 elderly people [119, 120].

A combined herbal supplement containing Rhodiola crenulata and Ginkgo biloba improved endurance performance in a clinical trial on 70 healthy male volunteers [121].

Acute mountain sickness is a condition with headaches, dizziness, and fatigue due to the rapid exposure to low oxygen at high elevation. In 2 clinical trials on 62 people, taking ginkgo extract 1 day before climbing high mountains reduced the incidence and severity of this syndrome [122, 123].

Again, the results are promising but insufficient to conclude for certain that ginkgo extract reduces fatigue. Larger, more robust clinical trials are needed to confirm these results.

3) Anti-inflammatory

In a pilot trial on 11 people with metabolic syndrome, the EGb 761 extract improved insulin sensitivity and reduced two markers of inflammation (CRP and IL-6) [99].

The combination of ginkgo and cordyceps improved micro-inflammation in a clinical trial on 65 people undergoing maintenance dialysis [124].

A constituent of Ginkgo biloba (bilobalide) reduced inflammatory pain in rats [125].

Another compound from ginkgo (ginkgolide A) reduced the inflammatory response of human umbilical vein endothelial cells (HUVECs) to high glucose levels (possibly mediated by the action of the STAT3 pathway) [126].

Several compounds isolated from Ginkgo biloba stem bark inhibited TNF alpha-induced NF-kB gene production activity in cells [127].

Two clinical trials and some animal and cell-based research cannot be considered sufficient to attest to the anti-inflammatory activity of Ginkgo biloba. Further clinical research is needed.

4) Cancer

In a small trial on 30 people with stomach cancer, oral capsules with ginkgo fruit carbohydrates reduced tumor size. These compounds reduced tumor growth and stimulated cancer cell death in cell-based studies [128].

In a small clinical trial on 30 Chernobyl workers, taking EGb 761 reduced mutagenic factors in the DNA. Ginkgo extract also prevented mutations in another trial on 23 people receiving radioactive iodine therapy for thyroid cancer. However, an observational study on over 3,000 people couldn’t associate regularly taking this extract with a reduced incidence of cancer [129, 130, 131].

EGb 761 protected against ear toxicity due to the anticancer drug cisplatin in a small trial on 15 people [132].

In 2 pilot trials on almost 100 people with late-stage pancreatic cancer, adding EGb 761 extract to the anticancer drug 5-FU slightly improved its effectiveness [133, 134].

EGb 761 protected against benzopyrene (BP)-induced forestomach cancer and against heart toxicity caused by the anticancer drug doxorubicin in mice [135, 136].

Ginkgo biloba had anticancer activity against liver and breast cancer cells [137, 138].

Although some clinical studies found anticancer effects, their size is small and their results are modest. Larger, more robust clinical trials are needed to determine the potential use of Ginkgo biloba in anticancer therapy.

5) Attention Deficit Hyperactivity Disorder

Ginkgo biloba extract EGb 761 (80-240 mg/day) improved ADHD symptoms and brain activity in 3 clinical trials on 136 children and adolescents. Because it was less effective than Ritalin, ginkgo may work better as an add-on to this drug [139, 140, 141].

Although the results are promising, three small trials are insufficient to back the use of ginkgo extract in children with ADHD. More clinical trials on larger populations are needed to confirm these preliminary results.

6) Respiratory Diseases

Ginkgo biloba extract decreased the infiltration of inflammatory cells (eosinophils and lymphocytes) into the airways and relieved inflammation in a clinical trial on 75 asthmatic people [142].

Ginkgo extract also reduced inflammation and improved the symptoms of interstitial lung disease in a clinical trial on 45 people [143].

An extract combining Ginkgo biloba, ginger, and Picrorhiza kurroa (AKL1) slightly improved chronic obstructive pulmonary disease (COPD) in a small trial on 20 people but not asthma in another one on 32 people [144, 145].

Compounds isolated from ginkgo improved respiratory conditions such as asthma and allergy through their anti-inflammatory activity in animals [146].

Again, more clinical trials on larger populations are needed to confirm the potential to use ginkgo extract in people with respiratory diseases such as asthma and COPD.

7) Premenstrual Syndrome

Ginkgo biloba extract reduced the severity of PMS symptoms in a clinical trial on 85 women. More clinical trials are needed to validate this preliminary finding [147].

Animal and Cell Research (Lack of Evidence)

No clinical evidence supports the use of Ginkgo biloba for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies should not be interpreted as supportive of any health benefit.

Infections

In test tubes, extracts of Ginkgo biloba potently inhibited bacteria that may cause food poisoning (Escherichia coli) and antibiotic-resistant infections (vancomycin-resistant Enterococcus) [148, 149]:

Both Ginkgo biloba extract and its ginkgolic acted as biofilm inhibitors against E. coli, Staphylococcus aureus, and Salmonella and Listeria isolates from chicken, suggesting their potential to prevent hospital-acquired infections and preserve the quality and safety of poultry products [150, 151].

Ginkgo biloba leaf extract also inhibited common flu viruses (influenza A and B) [152].

Note, however, that these are very preliminary results that haven’t been replicated in humans or even in animals. Further studies are needed to determine if Ginkgo biloba may be of any use in the treatment of the infections caused by these microbes.

Liver Function

In rats with non-alcoholic liver disease, Ginkgo biloba extract reduced antioxidant damage and liver scarring of tissue. Similarly, it reduced oxidative damage to the liver in rats given a toxic compound (carbon tetrachloride) [153, 154].

However, one study in mice found that extremely high doses increased the incidence of liver cancer [155].

Synergies, Side Effects, and Dosing

Long-term supplementation of n-3 polyunsaturated fatty acids (n-3 PUFA), lycopene and Ginkgo biloba extract improved cognitive function in a clinical trial on 41 elderly people [156].

Mice treated with Ginkgo biloba extract and ticlopidine showed higher recovery from acute thrombosis [157].

Ginkgo biloba and Codonopsis pilosula improved the cognitive function and overall health of 60 people aged 21-60 years [158].

Possible Side Effects and Interactions

This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects.

Call your doctor for medical advice about side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.

Although the supplement is considered generally safe, it may cause an upset stomach, headache, constipation, dizziness, and allergic reactions [159].

A spontaneous intracerebral hemorrhage occurred in a 56-year-old man with no unusual drug use or medical history other than taking ginkgo leaf extract (40 mg, 3x/day for 18 months) [160].

Ginkgo nuts contain a potent neurotoxin (4-O-methoxypyridoxine) that indirectly inhibits the enzyme glutamate decarboxylase. The resulting reduction in the levels of the neurotransmitter GABA increases the likelihood of seizures [161, 162].

Ginkgo biloba has been reported to cause spontaneous bleeding and may interact with blood thinners. A case of post-laparoscopic bleeding in a patient taking ginkgo has been reported [163, 164, 165].

Due to the lack of safety studies, pregnant or breastfeeding women should avoid Ginkgo biloba supplements.

Do not consume fresh Ginkgo seeds as they are poisonous and potentially deadly [166].

Dosage

Because ginkgo extract is not approved by the FDA for any condition, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor if Ginkgo biloba may be useful as a complementary approach in your case and which dose you should take.

A daily dose between 120 mg and 600 mg moderately enhanced a number of cognitive functions in healthy individuals [167].

A meta-analysis showed that a dosage of 240 mg might be necessary to yield clinically relevant effects in people with dementia [168].

About the Author

Carlos Tello

Carlos Tello

PhD (Molecular Biology)
Carlos received his PhD and MS from the Universidad de Sevilla.
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.

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