12 Health Benefits of Garlic: Health Effects Explained

Medically Reviewed By Peter Pace, MS, RDN, CSCS, CPT
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Garlic contains many nutrients and bioactive compounds, which may make it a beneficial and effective supplement for health. Historical use of garlic in medicine goes back centuries, and modern research is now working to investigate its benefits and efficacy as a clinical treatment option. You can take garlic by either consuming raw garlic or supplementing with garlic pills. There is evidence of positive effects on health with both options.

Read on to learn more about the health benefits of garlic, how it can improve your health, and effective use of garlic to achieve health benefits.

Is garlic good for you?

A row of garlic
Carles Rodrigo Monzo/Stocksy United

Garlic contains many vitamins, minerals, and other nutrients that are essential to the human diet. This includes nutrients such as fiber, manganese, selenium, vitamin C, several types of vitamin B, and other antioxidants. It also contains iron, calcium, potassium, and copper.

These nutrients are fundamental to human health, as they give us energy and allow the body to perform all of its essential functions.

Other compounds garlic contains, such as alliin, may have further beneficial effects. Alliin turns into

allicin when garlic is crushed or chopped.

One 2019 study of 27,437 older Chinese people suggested that those who frequently consumed garlic — more than five times per week — lived longer than those who ate it only rarely, or less than once per week.

Researchers also suggested that garlic may relate to a lower risk of all-cause mortality, meaning the death rate from any cause was lower.

Additionally, garlic has other diverse benefits on health.

1. Infection and immunity

Research has shown that garlic and its compounds may have anti-inflammatory, antibacterial, antifungal, and antiviral effects.

Researchers of one 2016 study observed that consumption of an aged garlic extract reduced the severity of colds and the flu. It reduced the number of symptoms, the amount of days on which illness affected function, and the number of sick days study participants had to take from school or work.

Researchers also suggested that garlic supplementation enhanced the function of immune cells. This relates to reduced inflammation.

2. Improved memory

One 2020 study suggests that certain compounds of garlic and garlic extracts may be neuroactive, meaning they can stimulate neural tissue.

Researchers of the study used a mature garlic extract to investigate its effects on cognitively impaired mice. Results suggest that garlic compounds positively contribute to learning and memory formation in animals, having a positive effect on brain function.

3. Improved blood pressure

Garlic may help improve blood pressure and health.

One 2019 study into the effectiveness of Kyolic Aged Garlic Extract observed that an aged garlic extract significantly lowered blood pressure, pulse pressure, and arterial stiffness.

Researchers also suggest that garlic supplements are highly safe, and that they can offer additional benefits for cardiovascular health, indicating garlic extract as a useful treatment.

However, researchers outline the need for further long-term trials to confirm garlic’s impact on cardiovascular-related mortality and morbidity.

4. Lower cholesterol

A 2016 investigation into the effects of garlic and lemon juice found favorable effects on cholesterol. Researchers in the 2016 investigation observed evidence that consuming one-half to one clove of garlic per day lowers cholesterol levels by around 9%. The researchers’ discussion of this statistic was based on a finding in an older 1993 meta-analysis.

However, in an older 1998 study also, researchers observed that garlic powders did not lower cholesterol levels, suggesting that raw garlic may be more beneficial for cholesterol.

Learn more about high cholesterol and how to treat it at our online cholesterol information center.

5. Reduced risk of heart disease

Due to its potential effects of lowering blood pressure and cholesterol, garlic may reduce the risk of heart disease.

The properties of garlic that are beneficial to cardiovascular health may also be due to how it enhances nitric oxide production. Nitric oxide is essential to maintaining healthy blood flow and blood pressure, as well as inhibiting arterial disease, inflammation, and blood clotting.

The 2020 study on the effectiveness of garlic supplements suggested that aged garlic extracts offer multiple benefits for cardiovascular health. Another 2016 study suggests that garlic supplementation may potentially reduce risk factors for cardiovascular disease and protect cardiovascular health.

However, many clinical studies use high dosage levels of garlic, which may not be suitable for everyone. If you are considering supplementation with garlic, first talk with your doctor.

6. Athletic performance

Many cultures have used garlic for strength and stamina.

Recent research has investigated whether garlic may support certain aspects of physical activity and recovery.

One 2015 study into garlic supplementation and aerobic exercise observed that the antioxidants of garlic could possibly decrease exercise-induced oxidative damage in males.

Oxidative damage occurs when unstable atoms called free radicals become unbalanced and react with other molecules in the body, causing damage. Antioxidants, such as those found in garlic, may help to alleviate this oxidative stress.

A 2016 study of six male subjects also suggests that garlic supplementation may improve muscle performance. After 10 days of supplementation with 5 milliliters of aged garlic extract, the participants’ muscle function and power improved.

7. Bone health

The antioxidants in garlic may also improve certain osteopathic or bone diseases.

A 2017 clinical trial investigated the effect of garlic tablets on females experiencing postmenopausal osteoporosis, which is a weakening of bones.

Researchers suggest that garlic consumption can reduce the oxidative stress associated with many diseases, including bone disorders.

Additionally, they suggest that both raw garlic and garlic-derived medicine may aid the absorption of calcium.

8. Nutritional and gut health

Garlic can act as a prebiotic, which stimulates the growth of healthy bacteria in the digestive system.

Dietary supplementation with garlic could help to maintain healthy gut microorganisms and improve overall health. Good gastrointestinal health could even support the health or function of other bodily systems.

Garlic also contains many nutrients that are essential to overall health.

9. Anti-inflammation

Garlic and its compounds may offer anti-inflammatory properties.

Inflammation is an important process of the immune system, as it can help protect the body. However, chronic inflammation may be linked to many diseases, including diabetes, arthritis, Alzheimer’s disease, and depression.

A diet that includes foods with anti-inflammatory properties, such as garlic, may help reduce the risk of illness and help avoid exacerbating existing inflammatory diseases.

10. Anticancer

Garlic and garlic compounds may offer certain anticancer properties.

Clinical studies suggest that garlic can have anticancer or preventative effects, including:

  • inhibiting the activation of carcinogens, compounds that can cause cancer
  • boosting enzymes that deactivate carcinogens
  • reducing inflammation that could relate to the development of cancer
  • supporting DNA repair
  • inhibiting the growth and spread of cancer and cancerous cells

However, more research is necessary to understand how these clinical properties may translate to practical cancer treatment and prevention methods, as well as how laboratory findings relate to dosage, formulas, lifestyle factors, and individual differences.

For example, one 2020 analysis suggests that garlic supplements were most beneficial for the prevention of gastric cancer in participants who did not drink alcohol.

11. Skin health

Due to its antioxidant and other biological properties, garlic may be an effective herbal remedy for certain skin health issues.

An older 2011 review of 23 studies into garlic in dermatology suggests that oral administration of garlic may aid immunity, microcirculation, and protect against UVB damage.

Researchers also suggest that using garlic extracts topically may improve skin health issues, including:

However, some people are allergic to garlic, and contact dermatitis or skin irritation can occur.

Garlic burn is also a common side effect of applying garlic to the skin. Crushed garlic can cause chemical burns, and application of garlic to the skin can cause an adverse reaction even with only brief contact.

Only introduce new supplements or treatments under the advice of a doctor. Stop use and seek immediate medical care for any serious skin irritation following application of a new treatment, including garlic.

12. Heavy metal toxicity

Supplementation of garlic may help to treat mild to moderate metal poisoning.

In a trial studying garlic as a treatment for lead poisoning that was published in 2012, researchers observed that treatment with garlic related to significant clinical improvements in symptoms.

Garlic treatment reduced blood lead concentration significantly, with researchers suggesting that garlic was just as effective as a typical medication for lead poisoning but clinically safer.

How to take garlic and garlic supplements

You can supplement with garlic by eating raw or cooked garlic, or by taking commercially available garlic pills, tablets, capsules, or liquids.

However, research associates different health benefits with different methods of supplementation, and what supplementation will be most effective will vary from person to person. For example, aged garlic may have more antioxidant properties compared with fresh garlic extract.

Additionally, certain processes such as cooking can alter the composition of the garlic and impact its biological effects, so raw garlic may offer more therapeutic benefits.

Garlic supplementation may not be suitable for everyone.

Garlic supplementation may not be safe for people such as:

  • those who are pregnant
  • those who are breastfeeding
  • those who take anticoagulant medication
  • those who are due to undergo surgery

Garlic supplements may vary in strength, and they can react negatively with medications and other supplements. It is thus important that you discuss taking garlic with your doctor before starting use.

What are the side effects of eating too much garlic?

Garlic in any amount, used both orally and topically, can have side effects. These can include:

  • breath or body odor
  • heartburn
  • upset stomach
  • allergic reaction
  • increased risk of bleeding
  • adverse interaction with other medications, herbs, foods, and supplements, including saquinavir (an HIV antiviral) and anticoagulants
  • chemical burns

Frequently asked questions

Here are some common questions about garlic and garlic supplementation.

Is it healthy to eat garlic every day?

Garlic is probably safe for everyday consumption in the amounts usually used in food.

Additionally, garlic and other vegetables give you beneficial nutrients.

How much garlic can you eat in a day?

Clinicians and other regulatory bodies have not yet determined standard safe or effective dosages of garlic for particular ailments or diseases.

Appropriate dosing will depend on individual and lifestyle factors, underlying conditions, and the condition you hope to improve.

Recent clinical investigation suggests that an effective daily dosage of garlic powder ranges from 150–2,400 milligrams, with aged garlic being effective at around 0.25–7.2 grams per day.

However, participants took these doses under clinical supervision with monitoring for other medical treatments and health conditions. Discuss your supplements and their dosages with your doctor before starting any new supplements.

Summary

Garlic and garlic extracts offer many potential health benefits, due to the nutritional properties of garlic and the compounds it contains.

Garlic benefits include areas of health concerning bone strength, infection and inflammation, skin health, cancer, and more.

However, much research is clinical and focuses on animal studies. Further research is necessary to confirm the effectiveness of garlic outside of clinical contexts, and to identify the most effective dosing and supplementation methods.

Garlic can have side effects, so contact your doctor before starting supplementation. Be sure to inform your medical care team of your supplement routine before starting other new treatments.

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Medical Reviewer: Peter Pace, MS, RDN, CSCS, CPT
Last Review Date: 2022 Apr 29
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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