What happens to your blood pressure when you eat garlic or take garlic supplements

Medically reviewed by Sohaib Imtiaz, MD

Key Takeaways

• Garlic may help lower blood pressure and offer similar benefits to some medications, but the evidence is limited.
• It's generally safe for most people, but can cause side effects, especially for those with GI issues or who take medications like blood thinners.
• Always talk to your healthcare provider before using garlic or any supplement to manage health conditions, and don't use it as a replacement for prescribed treatment.

Garlic may help lower blood pressure, especially in people with hypertension, whether eaten fresh or taken as a supplement. But since the research is mixed, it’s not strong enough to recommend garlic as a treatment on its own.

How Does Garlic Affect Blood Pressure?

Research indicates that garlic can lower blood pressure. Garlic can help support a 16% to 40% reduction in the risk of having a cardiovascular event.

Allicin, the main bioactive compound in garlic, can help lower blood pressure by:

• Interfering with angiotensin-converting enzymes (ACE): These vasoconstricting factors raise high blood pressure by constricting (narrowing) blood vessels. By reducing angiotensin, allicin promotes more unrestricted blood flow and lower blood pressure.
• Creating strong antioxidative and anti-inflammatory effects: These effects may protect blood vessels from damage, such as arterial stiffness, so they can better regulate blood pressure.
• Inducing vasodilation (widening blood vessels): This may be done through mechanisms that include the production of nitric oxide (NO), which relaxes blood pressure walls, resulting in lower blood pressure.

A meta-analysis of 12 trials involving 553 adults with uncontrolled high blood pressure found that garlic effectively reduced blood pressure, similar to the results expected with standard blood pressure drugs. In addition, garlic use showed fewer side effects than standard medications.

Although research suggests garlic can help lower blood pressure, it should still not be considered a treatment option.

How Much Garlic Does It Take?

Research shows that a variety of garlic formulations in the following dosages were used to lower blood pressure, including:

• Garlic powder containing egg yolk: 188 milligrams (mg) daily for 12 weeks
• Aged garlic extract: 240 to 2,400 mg daily for two to 23 weeks
• Raw garlic: 400 mg daily for six months
• Garlic powder: 600 to 2,400 mg daily for eight to 24 weeks
• Garlic oil: 12.3 mg daily for 16 weeks

Aged garlic extract delivered the most benefits, though results were achieved with all forms involved. In most cases, higher doses of 400 to 2,400 mg daily provided the best results.

Are Garlic Supplements Safe?

For most people, garlic supplements or garlic pills are a safe and convenient way to consume garlic when taken in the amounts directed. While garlic supplements are safe for most people when consumed as directed, you should consult with your healthcare provider before introducing garlic or any other new supplement into your daily routine.

Garlic supplements usually consist of dried and pulverized whole cloves. While garlic supplements don't typically cause harmful symptoms, they can trigger the following side effects in some people, including:

• Abdominal pain
• Body or breath odor
• Burping
• Constipation
• Diarrhea
• Heartburn
• Nausea, upset stomach
• Vomiting

If you experience any of these adverse effects, discontinue using garlic supplements and contact your healthcare provider for advice.

Call 911 and seek immediate medical attention if you have signs of a serious allergic reaction to garlic or other foods, including anaphylaxis, a life-threatening allergic reaction with symptoms such as difficulty breathing, chest tightness, irregular heartbeat, feeling of doom, or sudden cardiac arrest.

Who Should Avoid Garlic?

You may be more susceptible to adverse effects from garlic if you have certain health conditions or take certain drugs. Based on research evidence, you should limit or avoid garlic supplements if you have any of the following characteristics:

• Garlic allergy: Avoid garlic in all forms if you have a known allergy. If you have a food allergy to garlic, you may also have an allergy to other plants in the garlic family, which include onions, leeks, shallots, scallions, and chives.
• Chronic conditions affecting the gastrointestinal (GI) tract: Garlic can cause irritating heartburn in anyone. If you're more susceptible to this condition, you may be more likely to experience it with garlic supplements. Other GI conditions include gastroesophageal reflux disease (GERD) and ulcers.
• Pregnant or breastfeeding: There is little evidence to support the safe use of garlic supplements during pregnancy or while breastfeeding.
• Taking anticoagulants or other blood-thinning medications: Garlic supplements may increase the risk of bleeding if you take an anticoagulant such as Jantoven (warfarin) or Plavix (clopidogrel).
• Taking medication to lower high blood pressure: The properties of garlic that lower blood pressure may increase the effects of blood pressure–lowering medication, so your blood pressure is reduced too much.
• Preparing for surgery: Since garlic may increase the risk of bleeding, it may not be safe for people undergoing surgery. Advise your healthcare provider about using garlic supplements if you are scheduled for any type of surgery, including dental.
• Other medications: Garlic supplements may also impact the effectiveness and predictability of certain drugs, including birth control pills, nonsteroidal anti-inflammatory drugs (NSAIDs), blood sugar level-lowering drugs, and more.

Other Ways to Lower Blood Pressure Naturally

Most people with high blood pressure benefit from a combination of medication and natural remedies, including lifestyle changes known to impact blood pressure.

You may be able to lower blood pressure naturally with one of the following strategies:

• Stop smoking: Smoking can increase and worsen existing high blood pressure.
• Follow a healthy diet: Lower your salt intake and follow a diet rich in whole grains, lean protein, nuts, legumes, and low-fat dairy. This can help achieve and maintain healthy blood pressure.
• Limit alcohol: Drinking too much alcohol can increase your blood pressure. To avoid excess alcohol, experts advise that men limit their intake to two drinks daily, and women should consume no more than one daily drink.
• Lose weight if you have obesity: While most people can reach and maintain a healthy body weight with a combination of diet and exercise, consult your healthcare provider for alternative options if your efforts do not work.
• Stay active: Aim for 150 minutes (about 2.5 hours) of moderate-intensity exercise or 75 minutes of vigorous aerobic activity weekly to lower blood pressure. Incorporate strength training exercises at least twice weekly to support overall good health.
• Manage stress: Most people can reduce stress and tension by combining social connection, relaxation, and a regular sleep schedule of at least seven hours nightly. Other practices, such as meditation, gratitude, and joy, may also help lower blood pressure.

Read the original article on Verywell Health