Description

Obesity is a chronic disease associated with a wide range of adverse health outcomes, including type 2 diabetes mellitus, coronary heart disease, and other metabolic disorders. The global rise in obesity is driven in part by sedentary lifestyles and the widespread availability of calorie-dense foods. According to the World Health Organization, over one billion people worldwide are affected by obesity (BMI ≥ 30 kg/m²), with even more classified as overweight (BMI ≥ 25 kg/m²). This trend poses significant challenges not only to individual health but also to public health systems due to the high costs of treating obesity-related complications.

Lifestyle modification remains the cornerstone of effective weight management. For individuals with overweight but without comorbidities, the primary goal is to prevent further weight gain through increased physical activity and dietary adjustments. Evidence suggests that even modest weight loss of 5-10% can lead to clinically meaningful improvements in cardiovascular risk factors.

In this context, dietary supplements that support appetite regulation and satiety enhancement are of growing interest. Several plant extracts-including bitter melon, yerba mate, green tea, turmeric, and others-have shown potential to stimulate the secretion of glucagon-like peptide-1 (GLP-1), a gut hormone involved in satiety signaling, appetite suppression, and insulin secretion.

GLP-1 is secreted by intestinal L-cells in response to food intake and acts via GLP-1 receptors. However, native GLP-1 has a short half-life of approximately two minutes due to rapid degradation by the enzyme dipeptidyl peptidase-4 (DPP-4). Therefore, strategies that stimulate GLP-1 secretion or inhibit DPP-4 activity may enhance satiety and support weight control. While promising, current evidence is largely limited to in vitro and animal studies, and human data are lacking.

This randomized, double-blind, placebo-controlled clinical trial aims to investigate the effects of a commercially available dietary supplement (FitLine TopShape) on GLP-1 secretion and related metabolic parameters. The supplement contains extracts from purslane, bitter melon, dandelion, mulberry, yerba mate, and green coffee beans. Preliminary user data from an observational study (n=40) suggest that daily intake of the supplement may increase satiety and promote weight loss (mean reduction: -1.32 kg over four weeks; unpublished). In vitro assays indicate that the bioactive compounds may reduce DPP-4 activity and increase GLP-1 secretion (unpublished).

The primary objective of this study is to assess the effect of the supplement on GLP-1 secretion. Secondary outcomes include changes in DPP-4 activity, gastric inhibitory peptide (GIP), insulin, and C-peptide levels. Subjective measures of satiety, appetite, and food intake will be collected via validated questionnaires. Anthropometric data (weight, height, waist and hip circumference) will be recorded at baseline and after 12 weeks of intervention.

Participants (BMI 25-40 kg/m², age 18-50 years) will be randomized 1:1 to receive either the dietary supplement or placebo for 12 weeks. Blood samples will be collected in fasting state and at multiple time points post-ingestion of the capsule and a standardized liquid meal. The study will evaluate both acute hormonal responses and long-term effects on weight control.