Garlic Extract
Supplements · Cardiovascular & Anti-Inflammatory Herbs · Supplement, Typed Supps
Its key compound only forms once you crush or chew it.
Stage by stage
- Intake (Aged extract or powder): Allicin, garlic’s key compound, is unstable, so quality varies widely between products.
- Small intestine (Absorbed): Absorbed into the bloodstream.
- Bloodstream (Circulates): Circulates through the blood, where its mild blood-thinning effect also takes place.
- Blood pressure & lipids (Modest effects studied): Studied for modest effects on blood pressure and lipid levels, with a mild blood-thinning effect.
What the evidence supports
- Lowering blood pressure modestly — moderate evidence. Pooled trials show a small reduction, mainly in people who are hypertensive to begin with. Real, but smaller than any blood pressure medication.
- Lowering LDL cholesterol — limited evidence. Effects in trials are small and inconsistent, and better-controlled studies tend toward null.
- Preventing colds — limited evidence. One frequently cited trial found fewer colds. It has not been convincingly replicated.
Typical dose
The best-characterised dose is 600 to 900 mg daily of standardised garlic powder, providing roughly 3.6 to 5.4 mg of allicin potential. Aged garlic extract has been trialled across a much wider and less consistent range, from a few hundred milligrams to several grams daily, so its labels are harder to compare with each other.
Upper limit: No formal UL. Culinary amounts are safe; in practice the limit is the smell and the stomach.
Timing
With food — raw garlic in large amounts can irritate the stomach.
Time to effect
- Weeks: Modest blood pressure/lipid changes reported in studies.
Medication interactions
- Warfarin and antiplatelets: Adds to bleeding risk; stop before scheduled surgery. (high)
- HIV protease inhibitors (saquinavir): Garlic supplements substantially reduced blood levels in at least one study. (high)
Common myth
“Garlic supplements work as well as fresh garlic.” In reality: Allicin content varies enormously between products, making effects far less consistent than fresh garlic.
Food sources
More in Cardiovascular & Anti-Inflammatory Herbs
In the glossary
Sources