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Botanical

Garlic

Garlic (Allium sativum) is a bulb of the onion family, used as food and in traditional medicine for thousands of years. Crushing it releases allicin.

Also listed as Garlic Extract, Allium sativum, Garlic Bulb, Garlic Powder

CardiovascularLongevityGut HealthImmune Support

Who might see a blood-pressure change?

A meta-analysis of ten trials found reductions among participants with elevated systolic blood pressure, but not among those without it. Only three trials studied the high-pressure group. This supports a possible targeted use, while leaving important questions about long-term outcomes and harms. 1

Blood pressureMixed

Benefits are more plausible in people with high blood pressure; they were not demonstrated in the normal-pressure group. 1

Cholesterol changes are usually modest

An umbrella review found total-cholesterol reductions in most included meta-analyses, but less consistent results for LDL, HDL and triglycerides. NCCIH’s current summary describes small total- and LDL-cholesterol reductions in people with high cholesterol. These are changes in risk markers, not proof that a particular supplement prevents a heart attack. 2 3

Cholesterol balanceMixed

Total cholesterol generally improves, but the size and other lipid responses vary. 2 3

What do antioxidant findings mean?

A meta-analysis of twelve trials found changes in several blood markers of antioxidant capacity and oxidative stress. Studies lasted two to 24 weeks and used different doses. These measurements are useful research leads; they do not show that users feel better, age more slowly or avoid disease. 4

Oxidative stressToo little evidence

Blood-marker findings are promising but do not establish a patient-important benefit. 4

Will it prevent a cold?

NCCIH notes that the small studies suggesting an immune benefit have methodological weaknesses. The available research does not establish reliable cold prevention, despite the popularity of that claim. 3

Immune SupportToo little evidence

A few weak studies leave the clinical immune benefit uncertain. 3

Effects by health goal

Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.

Gut Health1 effect

Gut healthModerateBNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

Immune Support1 effect

Immune SupportModerateBNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

Other effects1 effect

InflammationModerateBNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

All studies

6 publications are linked to Garlic, newest first.

Garlic and Hypertension: Efficacy, Mechanism of Action, and Clinical Implications2024Effects of garlic supplementation on oxidative stress and antioxidative capacity biomarkers: A systematic review and meta‐analysis of randomized controlled trials2021The effects of garlic supplementation on oxidative stress markers: A systematic review and meta-analysis of randomized controlled trials.2020Effect of Garlic’s Active Constituents in Inflammation, Obesity and Cardiovascular Disease2020An umbrella review of garlic intake and risk of cardiovascular disease.2016Effects of Garlic on Blood Pressure in Patients with and Without Systolic Hypertension: A Meta-Analysis2008

Sources