Aged Garlic Extract

Built from two randomised placebo-controlled trials of aged garlic extract taken on top of blood-pressure medication by people whose hypertension was not controlled. Ried 2013 (PMID 23169470), a dose-response trial in 79 general practice patients over 12 weeks, gave 240, 480 or 960 mg a day: 240 mg did not lower systolic pressure compared with placebo, 480 mg lowered it by 11.8 mmHg (P=0.006), and 960 mg reached a borderline 7.4 mmHg at 8 weeks (P=0.07). Ried 2010 (PMID 20594781), in 50 patients over 12 weeks, found 960 mg a day lowered systolic pressure by 10.2 mmHg (p=0.03) in those starting at 140 mmHg or above, with no significant change in those below 140. The 960 mg point sits no higher than 480 mg because the one trial that compared doses found no extra benefit at the higher dose. 480 mg is the lowest dose with a significant fall. No optimal dose is set, because that trial's arms were small and 960 mg lowered pressure in the second trial, and no ceiling is set on this curve. A 2024 meta-analysis that reported a benefit only above the doses these trials tested has been retracted (PMID 39437887), and no point on this curve rests on it. Aged black garlic extracts dosed by their S-allyl cysteine content (PMID 35276764, 37686723) are a different preparation and are not placed on this axis, and neither is a 2,400 mg trial whose blood pressure result was a secondary before-and-after change in the garlic group (PMID 32349742).