Effects of Capsicum annuum supplementation on the components of metabolic syndrome: a systematic review and meta-analysis

Systematic review and meta-analysis of 11 studies including 609 adults aged 18 years or older from the United States, Korea, Japan, Australia, and China. Most participants were overweight or obese, with both men and women represented; intervention durations ranged from 4 to 12 weeks.

Capsicum annuum supplementation was tested in multiple formulations, including capsaicinoids, capsinoids, dihydrocapsiate, fermented red pepper paste, red pepper capsules, chili powder, and freshly chopped chili. Doses varied across studies, ranging from 1.25 g chili powder (5 mg/day capsaicin) to 34.5 g fermented red pepper paste or 3 to 9 mg/day of dihydrocapsiate or capsinoids, typically for 4 to 12 weeks, compared with placebo or control.

Capsicum annuum supplementation significantly lowered LDL-cholesterol and showed a marginal effect on body weight. No significant effects were observed for total cholesterol, HDL-cholesterol, triglycerides, glucose, or blood pressure. Across 11 studies, the evidence suggests a limited but potentially favorable lipid effect, with no consistent benefit on other metabolic syndrome components. The authors concluded that larger, better-designed trials are needed to confirm efficacy and safety.

The evidence base was small, with only 11 studies and 609 participants overall. Trial formulations, doses, and durations were heterogeneous, follow-up was short at 4 to 12 weeks, and the review was limited by risk of bias. Adverse-event reporting was inconsistent, which limits confidence in safety conclusions and generalizability.