Effects of curcumin and/or coenzyme Q10 supplementation on metabolic control in subjects with metabolic syndrome: a randomized clinical trial

Randomized clinical trial in adults with metabolic syndrome diagnosed by IDF criteria in Tehran, Iran. Active-arm sample sizes were 22 participants each: curcumin plus placebo, coenzyme Q10 plus placebo, and curcumin plus coenzyme Q10.

This 12-week randomized clinical trial tested oral curcumin and coenzyme Q10 in adults with metabolic syndrome. The curcumin arm received 200 mg per capsule once daily plus a matching placebo capsule; the coenzyme Q10 arm received 60 mg per capsule once daily plus a matching placebo capsule; and the combination arm received one curcumin capsule and one coenzyme Q10 capsule daily, all taken before lunch.

Curcumin improved lipid parameters, while coenzyme Q10 alone and the curcumin plus coenzyme Q10 combination did not produce meaningful benefits on metabolic syndrome components. In the curcumin arm, triglycerides fell by −58.0 ± 49.1 (P < 0.001), HDL cholesterol rose by 10.0 ± 5.3 (P < 0.001), total cholesterol fell by −30.9 ± 35.1 (P < 0.001), and LDL cholesterol fell by −14.1 ± 6.2 (P < 0.001). In the coenzyme Q10 arm, triglycerides changed by −9.8 ± 30.4 (P = 0.08) and total cholesterol by −10.1 ± 30.2 (P = 0.06), with no significant changes in blood pressure, waist circumference, or fasting plasma glucose. In the combination arm, triglycerides decreased by −16.0 ± 48.4 (P = 0.01), but other lipid and metabolic outcomes were not significantly changed.

Small active-arm sample size (22 per group) and short 12-week duration limit certainty and longer-term inference. The study was conducted in a single city in Iran, which may restrict generalizability. Diet and physical activity were monitored/advised, but broader lifestyle control and external validity remain limited.