Background: Dihydrocapsiate is a capsinoid found in chili peppers. Dihydrocapsiate is similar to capsaicin, which is known for its thermogenic properties.
Objective: The objective was to determine the acute and chronic effect of dihydrocapsiate on resting metabolic rate (RMR).
Design: Seventy-eight healthy subjects in a double-blind, parallel-arm trial were randomly assigned to 3 groups receiving 0 (placebo), 3, or 9 mg dihydrocapsiate/d for 28 d. After a 10-h overnight fast, RMR was measured by indirect calorimetry for 30 min before and 120 min after ingestion of dihydrocapsiate.
Results: RMR was similar in the 3 groups before dosing on day 1 [1714 ± 41 kcal/d (0 mg), 1760 ± 41 kcal/d (3 mg), and 1694 ± 38 kcal/d (9 mg)] and after acute dosing (41 ± 17, 55 ± 17, and 3 ± 24 kcal/d for 3-mg, 9-mg, and placebo groups, respectively). When the chronic effect of dihydrocapsiate on RMR was calculated from the average 2-h RMR on day 28 minus the 30-min preingestion RMR at baseline, a borderline effect in subjects receiving 3 mg dihydrocapsiate/d compared with placebo was observed (61 ± 24 kcal/d compared with -1 ± 12 kcal/d, P = 0.054), whereas no significant increase in RMR in comparison with placebo was noted for the 9-mg/d dose (48 ± 23 kcal/d compared with -1 ± 12 kcal/d, P = 0.12). When data from both groups were combined, the thermic effect of dihydrocapsiate reached significance (53 ± 9 kcal/d compared with -1 ± 12 kcal/d in the placebo group, P = 0.04). Fat oxidation was unaffected by dihydrocapsiate.
Conclusion: After 1 mo of supplementation, dihydrocapsiate had a small thermogenic effect of ≈50 kcal/d, which is in the range of day-to-day RMR variability. This trial was registered at clinicaltrials.gov as NCT00999297.