- What other names is Garlic known by?
- What is Garlic?
- Is Garlic effective?
- How does Garlic work?
- Are there safety concerns?
- Are there any interactions with medications?
- Dosing considerations for Garlic.
Garlic is used for many conditions related to the heart and blood system. These conditions include high blood pressure, low blood pressure, high cholesterol, inherited high cholesterol, coronary heart disease, heart attack, reduced blood flow due to narrowed arteries, and "hardening of the arteries" (atherosclerosis).
Some people use garlic to prevent colon cancer, rectal cancer, stomach cancer, breast cancer, prostate cancer, multiple myeloma, and lung cancer. It is also used to treat prostate cancer and bladder cancer.
Garlic has been tried for treating an enlarged prostate (benign prostatic hyperplasia; BPH), cystic fibrosis, diabetes, osteoarthritis, hayfever (allergic rhinitis), traveler's diarrhea, high blood pressure late in pregnancy (pre-eclampsia), yeast infection, flu, and swine flu. It is also used to prevent tick bites, as a mosquito repellant, and for preventing the common cold, and treating and preventing bacterial and fungal infections.
Garlic is also used for earaches, chronic fatigue syndrome, menstrual disorders, abnormal cholesterol levels caused by HIV drugs, hepatitis, shortness of breath related to liver disease, stomach ulcers caused by H. pylori infection, exercise performance, exercise-induced muscle soreness, a condition that causes lumps in the breast tissue called fibrocystic breast disease, a skin condition called scleroderma, and lead toxicity.
Other uses include treatment of fever, coughs, headache, stomach ache, sinus congestion, gout, joint pain, hemorrhoids, asthma, bronchitis, shortness of breath, low blood sugar, snakebites, diarrhea and bloody diarrhea, tuberculosis, bloody urine, a serious nose and throat infection called diphtheria, whooping cough, tooth sensitivity, stomach inflammation (gastritis), scalp ringworm, and a sexually transmitted disease called vaginal trichomoniasis. It is also used for fighting stress and fatigue.
Some people apply garlic oil to their skin or nails to treat fungal infections, warts, and corns. It is also applied to the skin for hair loss and thrush.
Garlic is used in the vagina for yeast infections.
Garlic is injected into the body for chest pain.
In foods and beverages, fresh garlic, garlic powder, and garlic oil are used to add flavor.
Garlic seems to also lower blood pressure in people with high blood pressure and possibly slow "hardening of the arteries."
There is also some evidence that eating garlic might reduce the chance of developing some cancers such as cancer of the colon, and possibly stomach cancer and prostate cancer. But there is no reliable evidence that garlic is helpful for people who already have cancer.
Some people with diabetes try garlic to help lower blood sugar. But garlic does not seem to be effective for this use.
There isn't enough information to know if garlic is effective for the other conditions people use it for, including: treating a special condition involving high cholesterol in people with HIV/AIDS, earaches, arthritis, allergies, colds, flu, traveler's diarrhea, and others.
Possibly Effective for...
- Hardening of the arteries (atherosclerosis). As people age, their arteries tend to lose their ability to stretch and flex. Garlic seems to reduce this effect. Taking a specific garlic powder supplement (Allicor, INAT-Farma, Moscow, Russia) twice daily for 24 months seems to reduce how much hardening of the arteries progresses. Higher doses of this product seem to provide more benefits in women than men when taken over a four year period. Research with other products containing garlic along with other ingredients (Kyolic, Total Heart Health, Formula 108, Wakunga) have also shown benefits.
- Colon cancer, rectal cancer. Research suggests that eating garlic can reduce the risk of developing colon or rectal cancer. Also, in people diagnosed with a certain type of colon and rectal tumors, taking high doses of aged garlic extract daily for 12 months seems to reduce the risk of developing new tumors. However, other garlic supplements do not seem to offer the same benefit.
- High cholesterol. While some conflicting research exists, the most reliable evidence to-date suggests that taking garlic can reduce total cholesterol by around 15 mg/dL and low-density lipoprotein (LDL, "bad" cholesterol) by around 6 mg/dL in people with high cholesterol levels. Garlic appears to work best if taken daily for more than 8 weeks. However, taking garlic doesn't help increase high-density lipoprotein (HDL, "good" cholesterol) or lower levels of other blood fats called triglycerides.
- High blood pressure. Some research shows that garlic by mouth can reduce blood pressure by as much as 7% or 8% in people with high blood pressure. Most studies have used a specific garlic powder product (Kwai, from Lichtwer Pharma).
- Prostate cancer. Men in China who eat about one clove of garlic daily seem to have a 50% lower risk of developing prostate cancer. Also, population research shows that eating garlic may be associated with a reduced risk of developing prostate cancer. But other research suggests that eating garlic does not affect prostate cancer risk in men from Iran. Early clinical research suggests that taking garlic extract supplements might reduce the risk of prostate cancer or reduce symptoms associated with prostate cancer.
- Tick bites. People who consume high amounts of garlic over about an 8-week period seem to have a reduced number of tick bites. But it's not clear how garlic compares to commercially available tick repellants.
- Ringworm. Applying a gel containing 0.6% ajoene, a chemical in garlic, twice daily for one week seems to be as effective as antifungal medication for treating ringworm.
- Jock itch. Applying a gel containing 0.6% ajoene, a chemical in garlic, twice daily for one week seems to be as effective as antifungal medication for treating jock itch.
- Athlete's foot. Applying a gel containing 1% ajoene, a chemical in garlic, seems to be effective for treating athlete's foot. Also, applying a garlic gel with 1% ajoene seems to be about as effective as the medicine Lamisil for treating athlete's foot.
Possibly Ineffective for...
- Breast cancer. Taking garlic does not seem to reduce the risk of developing breast cancer.
- Cystic fibrosis. Research suggests that taking garlic oil macerate daily for 8 weeks does not improve lung function, symptoms, or the need for antibiotics in children with cystic fibrosis and lung infection.
- Diabetes. Some research suggests that taking a specific garlic product (Allicor, INAT-Farma, Moscow, Russia) along with antidiabetes medication for 4-24 weeks can reduce blood sugar, cholesterol, and triglycerides in people with diabetes. However, analyses of research suggest that garlic does not seem to have any effect on blood sugar or cholesterol in people with or without diabetes.
- Inherited high cholesterol. In children with high levels of low-density lipoprotein (LDL or "bad") cholesterol, taking garlic powdered extract by mouth does not seem to improve cholesterol levels or blood pressure.
- Infections caused by helicobacter pylori (H. pylori) bacteria. Taking garlic by mouth for H. pylori infection used to look promising due to laboratory evidence showing potential activity against H. pylori. However, when garlic cloves, powder, or oil is used in humans, it does not seem to help treat people infected with H. pylori.
- Lung cancer. Taking garlic by mouth does not seem to reduce the risk of developing lung cancer.
- Mosquito repellent. Taking garlic by mouth does not seem to repel mosquitos.
- Leg pain caused by poor blood circulation in the legs (peripheral arterial disease or PAD). Taking garlic by mouth for 12 weeks does not seem to reduce leg pain when walking due to poor circulation in the legs.
- High blood pressure in pregnancy (pre-eclampsia). Early evidence suggests that taking a specific garlic extract (Garlet) daily during the third trimester of pregnancy does not reduce the risk of developing high blood pressure in women who are at high risk or pregnant for the first time.
Insufficient Evidence to Rate Effectiveness for...
- Hair loss (alopecia areata). Early evidence suggests that applying a garlic 5% gel along with a topical steroid for 3 months increases hair growth in people with hair loss.
- Chest pain (angina). Early research suggests that administering garlic intravenously (by IV) for 10 days reduces chest pain compared to intravenous nitroglycerin.
- Benign prostatic hyperplasia (BPH). Early research suggests that taking a liquid garlic extract daily for one month reduces prostate mass and urinary frequency. But the quality of this research is questionable.
- Common cold. Early research suggests that garlic might reduce the frequency and number of colds when taken for prevention.
- Clogged arteries (coronary heart disease). Some early research suggests that taking a specific garlic product (Allicor, INAT-Farma, Moscow, Russia) for 12 months reduces the risk of sudden death and heart attack in people at risk for developing clogged arteries. Other early research suggests that taking a supplement containing aged garlic (Kyolic, Total Heart Health, Formula 108, Wakunga) might prevent clogged arteries from worsening.
- Corns. Early research suggests that applying certain garlic extracts to corns on the feet twice daily improves corns. One particular garlic extract that dissolves in fat seems to work after 10-20 days of treatment.
- Cancer in the esophagus. Early research on the use of garlic for preventing cancer in the esophagus is inconsistent. Some evidence suggests that eating raw garlic does not prevent the development of cancer in the esophagus. However, other population research suggests that consuming garlic weekly does decrease the risk of developing cancer in the esophagus.
- Muscle soreness after exercise. Early evidence suggests that taking allicin, a chemical in garlic, daily for 14 days can reduce muscle soreness after exercise in athletes.
- Exercise performance. Early research suggests that taking a single 900 mg dose of garlic before exercise can increase endurance in young athletes.
- Lumpy breast tissue (fibrocystic breast disease). Early research suggests that taking a specific combination product (Karinat, INAT-Farma, Moscow Russia) containing garlic, beta-carotene, vitamin E, and vitamin C twice daily for 6 months reduces the severity of breast pain, premenstrual syndrome, and lumpy breast tissue in people with fibrocystic breast disease.
- Stomach cancer. Some research suggests that eating more garlic is linked to a lower risk of developing stomach cancer. But taking a specific aged garlic extract (Kyolic, Wakunaga Pharmaceutical Co) does not seem to reduce the risk of developing pre-cancer in the stomach.
- Stomach inflammation (gastritis). Early research suggests that taking a specific combination product containing garlic (Karinat, INAT-Farma, Moscow Russia) twice daily for 6 months improves digestion, stops the growth of certain bacteria (H. pylori), and reduces the risk of stomach cancer in people with stomach inflammation. However, the effect of garlic alone has not been determined.
- Hepatitis. Early research suggests that taking garlic oil together with diphenyl-dimethyl-dicarboxylate improves liver function in people with hepatitis. However, the effects of garlic alone are not clear.
- Shortness of breath and low oxygen levels associated with liver disease (hepatopulmonary syndrome). Early research suggests that taking garlic oil for 9-18 months might improve oxygen levels in people with hepatopulmonary syndrome.
- Lead poisoning. Early research suggests that taking garlic three times daily for 4 weeks can reduce blood lead concentrations in people with lead poisoning. But it does not seem to be more effective than D-penicillamine.
- Cancer of certain bone marrow cells (multiple myeloma). Early research suggests that taking garlic might be linked with a lower risk of developing cancer of the plasma cells in the bone marrow.
- Thrush (oral candidiasis). Early research suggests that applying garlic paste to affected areas in the mouth can increase the healing rate in people with oral thrush.
- Mouth ulcers (oral mucositis). Early research suggests that using a garlic mouthwash three times daily for 4 weeks improves redness in people with mouth sores. People seem to be more satisfied with garlic than the drug nystatin, but it is less effective.
- Hardening and tightening of the skin and connective tissue (scleroderma). Research suggests that taking garlic daily for 7 days does not benefit people with scleroderma.
- Vaginal yeast infections. Some early research suggests that applying a vaginal cream containing garlic and thyme nightly for 7 nights is as effective as clotrimazole vaginal cream for treating yeast infections. But other early research suggests that taking garlic (Garlicin, Nature's Way) twice daily for 14 days does not improve symptoms.
- Warts. Early evidence suggests that applying a specific fat-soluble garlic extract to warts on the hands twice daily removes warts within 1-2 weeks. Also, a water-soluble garlic extract seems to provide modest improvement, but only after 30-40 days of treatment.
- Weight loss. Early research suggests that taking a combination product (Prograde Metabolism) containing many different extracts including garlic root extract twice daily for 8 weeks reduces body weight, fat mass, and waist and hip circumference when used together with diet and exercise.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Next: How does Garlic work?
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