Capsaicinoids, compounds found in chili peppers of the genus Capsicum, are responsible for their spiciness and may have potential benefits in weight control and cardiometabolic health. They act on processes such as appetite regulation, fat burning, inflammation, and metabolism, although their effects vary among individuals, possibly due to genetic factors. In Mexico, where chili consumption is high and obesity is a significant public health problem, it is particularly relevant to study these genetic variations. The proposed research aims to identify genetic markers that can predict the response to capsaicinoid supplementation and thus develop personalized nutritional strategies for the treatment of obesity and its complications.

This study is a clinical investigation designed to understand how a natural compound found in chili peppers may influence the health of individuals with excess body weight, and why some people respond better than others to this type of intervention.

In recent years, it has been observed that certain compounds present in foods can affect metabolism-that is, how the body uses energy, regulates appetite, and stores fat. However, not all individuals respond in the same way to these compounds. This suggests that there are individual differences, possibly related to genetics, that may modify their effects.

The study will be conducted with a small group of adults with excess body weight, who will be randomly assigned to one of two groups. One group will receive daily supplementation with capsules containing an active compound derived from chili peppers, while the other group will receive identical capsules without the active ingredient (placebo). Neither the participants nor the researchers will know who receives which treatment during the study, helping to ensure more objective results.

The intervention will last 16 weeks, during which changes in body weight, body composition (such as fat mass), and metabolic health indicators such as blood glucose and lipid levels will be evaluated.

In addition to assessing the overall effects of the supplement, the study also aims to determine whether genetic characteristics can explain why some individuals show better responses than others. This could, in the future, support the development of more personalized dietary strategies tailored to each person's biological needs.

Overall, this research aims to contribute to the understanding of the potential of chili-derived compounds in supporting weight management, while also advancing toward a more personalized approach in nutrition and health.

Inclusion Criteria:

• Adults diagnosed with overweight or obesity within the age range established for the study
• Willingness to participate in the study
• Signed informed consent form

Exclusion Criteria:

• History of thyroid or metabolic disorders requiring pharmacological treatment, such as diabetes mellitus or coronary heart disease
• Pregnant or breastfeeding women
• Active smokers
• High alcohol consumption, defined as >20 g/day in women and >40 g/day in men
• Use of hypocaloric diets or weight-loss medications within the three months prior to study initiation
• Daily chili consumption or high habitual intake of capsaicinoids
• Known hypersensitivity to capsaicinoids
• Gastrointestinal disorders, such as ulcerative colitis or irritable bowel syndrome

Individual participant data will not be shared with other researchers. The information collected during the study will be used exclusively for the purposes of the present research and will be analyzed in aggregate form. Confidentiality of the data will be ensured through anonymization and compliance with applicable ethical guidelines and data protection regulations.

Participants will be randomly assigned to one of two intervention groups: capsaicin supplementation (CAP) or placebo (PLA). The study will be conducted under a double-blind design, in which both participants and researchers will remain unaware of the treatment allocation throughout the entire intervention period.