Ingredient guide
Garlic supplements, especially aged garlic and standardised garlic powder, lower blood pressure modestly in people with raised readings. The cholesterol evidence is more mixed. Garlic is well tolerated apart from odour and a small bleeding-risk caution.
Moderate evidenceGarlic is a kitchen staple that has been used as a remedy for thousands of years. As a supplement, it comes in several forms. Garlic powder is standardised to allicin, the famous sulphur compound formed when fresh garlic is crushed. Aged garlic extract is mellower, with much less allicin but different sulphur compounds that are well absorbed.
Garlic's sulphur compounds appear to relax blood vessels by nudging up nitric oxide, a signal that widens vessels and lowers pressure. The compounds also influence platelet stickiness, which is why garlic has a mild blood-thinning effect. Some compounds may also influence how the body handles cholesterol, though this part of the story is weaker.
For blood pressure, the evidence is reasonably consistent. Meta-analyses of randomised trials report that garlic, especially aged garlic extract, lowers systolic blood pressure by around 5 to 8 mmHg in people with raised readings, with smaller drops in diastolic pressure. The effect is comparable to some first-line blood pressure medicines on paper, though garlic is a complement rather than a replacement.
For cholesterol, the picture is mixed. Some trials and meta-analyses show small reductions in total and LDL cholesterol with garlic powder, while others find no clear effect. Form and dose seem to matter. We grade the overall evidence as moderate. Garlic is a sensible add-on for blood pressure, with weaker support for cholesterol on its own.
For blood pressure, aged garlic extract at 600 mg to 2,400 mg per day, or a standardised garlic powder at 600 mg to 900 mg per day, taken for at least two to three months, matches what trials used. If you take blood thinners or are heading for surgery, talk to a healthcare provider first, and consider stopping garlic supplements ahead of any planned procedure.
Trials commonly use aged garlic extract at 600 mg to 2,400 mg per day, or garlic powder around 600 mg to 900 mg per day standardised to allicin. Allow at least 8 to 12 weeks. Take with food to limit stomach upset. Ask your healthcare provider before starting if you take blood-thinning medicine.
In meta-analyses of trials, yes, by around 5 to 8 mmHg in people with raised readings. The effect is modest but real, especially with aged garlic extract.
Some, but trials use concentrated supplements with measured allicin or aged garlic. Cooking destroys much of the allicin, so a daily clove is a fraction of the trial dose.
Often, yes. Aged garlic extract is the most odour-free option. Enteric-coated capsules help, though absorption can vary.
Use caution. Garlic has a mild blood-thinning effect, so combining high-dose supplements with warfarin, aspirin, or clopidogrel needs medical input.
