Black Garlic

Also called

Aged Black Garlic

Traditional use

These are traditional uses, not proven treatments.

• Nobody knows exactly where black garlic came from. It's thought to have been eaten in Korea, Japan and Thailand since ancient times. In recent years it has become a fast-growing health food.[1]Study

Laboratory & animal research

Lab and animal results show what might be worth studying in people. They don't show that the herb has these effects in humans.

• Black garlic is made by keeping whole garlic bulbs warm (60–90 °C) and humid for 15 to 90 days, with nothing added. Lab analyses show this turns the cloves black, chewy and sweet, and changes what's in them.

  • Much less allicin, the compound behind fresh garlic's sharp smell
  • More S-allyl cysteine (SAC), a more stable sulfur compound
  • More sugars and more plant antioxidants (polyphenols)

  The amounts vary a lot with how it's made, because there's no standard method.[4]Study

  Technical detail: browning comes from the Maillard reaction, which forms melanoidins and 5-hydroxymethylfurfural (HMF). Allicin 3.45 g/kg in fresh garlic vs 0.16–0.93 g/kg; SAC 19.61 vs 28.78–124.67 µg/g; polyphenols 13.91 vs 25.81–58.33 mg GAE/g.

• In lab tests and animal studies, black garlic and its extracts acted as antioxidants and lowered inflammation signals. They also slowed or killed some cancer cells, lowered blood sugar in diabetic rats, and reduced weight and blood fats in rats fed a high-fat diet. Researchers don't yet know which of its compounds are responsible.[4]Study

  Technical detail: DPPH and ABTS IC50 166.3 and 108.1 µg/mL; extract at 120 mg/kg protected mice from LPS-induced septic shock; 1% or 3% extract in the diet of diabetic rats; 0.2–1.5% black garlic in the diet of high-fat-fed rats.

Research in people

• In a Korean trial, 60 adults with mildly high cholesterol took 6 g of aged black garlic or a placebo every day for 12 weeks, and 55 finished. Compared with placebo, black garlic didn't change total cholesterol, LDL ("bad") cholesterol or triglycerides. It did raise HDL ("good") cholesterol and lowered apolipoprotein B, a blood protein linked to heart disease risk. No side effects were reported.[2]Review or trial

  Technical detail: double-blind, randomized, placebo-controlled; analyzed 28 black garlic vs 27 placebo; LDL-C/apoB ratio increased.

• In a Spanish study, 62 adults aged 40 to 64 ate 4 cloves (12 g) of black garlic a day for 12 weeks. Half had high cholesterol and half didn't. There was no placebo group, so each person's results were compared before and after.

  • Some blood markers linked to healthy blood vessels improved in both groups, while two others went up.
  • In people without high cholesterol, total, LDL and HDL cholesterol all went up.
  • Blood pressure and weight didn't change, and safety blood tests stayed normal.

  The authors say longer studies are needed.[6]Study

  Technical detail: ApoA1 rose by about 11 mg/dL in both groups; MCP-1 fell 13.9% (hypercholesterolemic) and 7.2% (non-hypercholesterolemic); VCAM-1 fell 12.5% in the hypercholesterolemic group; atherogenic index fell from 3.86 to 3.54 in the non-hypercholesterolemic group; NCT05082350.

• In a Spanish trial, 67 adults with moderately high LDL cholesterol took a tablet of 250 mg aged black garlic extract or a placebo each day. Each person took both, for 6 weeks each, with a 3-week break between. On black garlic, diastolic blood pressure (the bottom number) was about 3.6 mm Hg lower than on placebo. The drop was seen in men but not in women. Cholesterol didn't change compared with placebo. Two authors worked for the company that makes the extract.[7]Review or trial

  Technical detail: randomized, crossover, double-blind; 1.25 mg S-allyl-L-cysteine per tablet; DBP −3.62 mm Hg (95% CI −6.2 to −0.99) vs placebo; men −5.85 mm Hg (−10.5 to −1.3); SBP −1.51 mm Hg (−9.1 to 6.1), not significant; NCT04010565.

• In a Spanish trial, 81 adults with mild (grade 1) high blood pressure who already took blood pressure medicine added a 250 mg aged black garlic extract tablet or a placebo each day for 12 weeks; 77 finished. Blood pressure fell slightly more with black garlic: about 1.8 mm Hg for the top number and 1.5 mm Hg for the bottom number. The company that makes the extract funded the study and employed some of the authors.[3]Review or trial

  Technical detail: randomized, triple-blind, placebo-controlled; 0.25 mg S-allyl-cysteine a day; SBP −1.8 mm Hg (95% CI 0.7 to 4.1), DBP −1.5 mm Hg (0.3 to 3.0); nitric oxide +10.3 µM; uric acid −0.3 mg/dL; ACE activity −9.3 U/L.

• In another Spanish trial, 75 adults with mild (grade 1) high blood pressure finished 12 weeks of a daily 250 mg aged black garlic extract or a placebo. Black garlic didn't change total, LDL or HDL cholesterol or triglycerides. More detailed blood fat tests hinted at small changes, but the authors say these need confirming in larger trials. The extract's maker funded the study.[8]Review or trial

  Technical detail: randomized, triple-blind, placebo-controlled; NMR lipoprotein subclass analysis (exploratory); NCT04915053.