In the present study, we found that C. annuum has marginally significant effects on body weight. Capsaicin is known to promote negative energy balance by increasing satiety and suppressing hunger, reducing energy and fat intake, and inducing thermogenesis. Capsinoids, including capsiate and dihydrocapsiate, are also known to exert beneficial effects on energy balance. Reinbach et al., reported that CH-19 sweet pepper (non-pungent) reduces energy intake during positive energy balance. Additionally, CH-19 sweet pepper is associated with increased oxygen consumption, diet-induced thermogenesis, and an activated sympathetic nervous system (SNS). Furthermore, a meta-analysis revealed that capsiate increases energy expenditure (EE), but capsaicin has no overall effect on EE; however, both capsaicin and capsiate enhance fat oxidation.

The effects of C. annuum on weight management are due to the activation of transient receptor potential vanilloid type 1 (TRPV1) receptors. In a preclinical study, dose-dependent administration of a TRPV1 agonist, capsaicin, prevented adipogenesis in stimulated 3T3-L1-preadipocytes, and oral administration of capsaicin prevented obesity in males. Non-pungent capsiate is also an exogenous agonist of TRPV1 receptors and is associated with improved body metabolism including glucose homeostasis and obesity. TRPV1 activation leads to activation of the SNS, and inhibition of food intake by SNS activation accounts for reduced body fat stores and weight loss. Some herbs and their active compounds, including several piperine analogs from Piper nigrum, can also reduce weight through TRPV1-dependent mechanisms.