Serrano · Nutrients 2023 · Randomized, triple-blind, placebo-controlled parallel trial · n=?

Antihypertensive Effects of an Optimized Aged Garlic Extract in Subjects with Grade I Hypertension and Antihypertensive Drug Therapy: A Randomized, Triple-Blind Controlled Trial.

Cited 31 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial

PubMed 37686723 · doi:10.3390/nu15173691 · record verified 2026-08-29

What was done

A randomized, triple-blind, placebo-controlled parallel trial was conducted to evaluate the antihypertensive effects of an optimized aged black garlic extract providing low-dose s-allyl-cysteine (SAC; 0.25 mg/day) over 12 weeks. The study population consisted of individuals diagnosed with Grade I hypertension who were currently receiving standard antihypertensive drug therapy.

What was found

SAC supplementation resulted in a reduction in systolic blood pressure of 1.8 mmHg (95% CI: 0.7 to 4.1) and diastolic blood pressure of 1.5 mmHg (95% CI: 0.3 to 3.0). Secondary biochemical changes included an increase in blood nitric oxide (10.3 µM, 95% CI: 1.1 to 19.5) and antioxidant capacity (7 × 10^-3 µM TE/min, 95% CI: 1.2 to 13 × 10^-3), along with decreases in uric acid (-0.3 mg/dL, 95% CI: -0.5 to -0.001) and ACE activity (-9.3 U/L, 95% CI: -18.4 to -0.4). No changes were observed in endothelial function or inflammatory cytokines.

Why it matters

The findings suggest that an optimized aged garlic extract may serve as a low-dose adjuvant therapy to provide modest additional blood pressure lowering in patients already receiving antihypertensive medication.

Limits

The abstract does not report the total sample size or participant characteristics beyond Grade I hypertension with drug treatment. Blood pressure reductions were small (under 2 mmHg), endothelial function and inflammatory markers showed no improvement, and long-term outcomes beyond 12 weeks were not measured.

Cited by