Effect of a Dietary Supplement on Hormones Involved in Appetite Regulation in Overweight and Obese Adults

March 27, 2026 updated by: FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation

Effect of a Dietary Supplement (FitLine TopShape) on the Incretin Response

Obesity is a chronic condition linked to numerous health risks and affects more than one billion people worldwide. While pharmacological treatments such as incretin-based therapies are available, they may have side effects, are not suitable for all patients, and adherence can be limited. Dietary supplements that influence appetite and satiety may represent an alternative or complementary approach.

This study will evaluate whether a dietary supplement containing plant extracts stimulates the intestinal incretin response. The primary focus is the effect on glucagon-like peptide-1 (GLP-1) secretion. Secondary outcomes include dipeptidyl peptidase-4 (DPP-4), gastric inhibitory peptide (GIP), and insulin, as well as measures of appetite, satiety, food intake, and anthropometrics.

The trial is designed as a 12-week, double-blind, randomized, placebo-controlled parallel-group study in adults with overweight or obesity (BMI 25-40, age 18-50). Participants will receive either the dietary supplement or placebo. Blood samples will be collected at baseline and after 12 weeks, both fasting and following capsule intake and a standardized liquid meal. Anthropometric measurements and visual analog scales (VAS) for hunger and satiety will also be assessed.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed 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.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Austria
    • Salzburg
      • Salzburg, Salzburg, Austria, 5020
        • Salzburger Universitätsklinikum

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Signing the consent form
  • BMI 25-40 kg/m²
  • Age 18-50 years

Exclusion Criteria:

  • Known allergy to ingredients in the administered substances
  • Type 1 or 2 diabetes
  • Pregnancy
  • Breastfeeding mothers
  • Acute infectious disease
  • Renal insufficiency

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Dietary Supplement
Participants receive a dietary supplement: Capsule preparation containing hypromellose, calcium phosphate, inulin, yeast extract (Saccharomyces cerevisiae), bitter melon extract, green coffee bean extract, white mulberry extract, purslane extract, peppermint leaf extract, dandelion extract, green mate extract, zinc gluconate, ginger extract, biotin and yellow iron oxide (E172 - capsule colouring)
Dietary supplement: Intervention: Dietary Supplement with Plant Extracts
Capsule containing a blend of plant extracts, administered twice daily three capsules (total six capsules), 30-60 minutes before main meals, for 12 weeks.
Placebo Comparator: Placebo
Participants receive a capsule preparation containing hypromellose, calcium phosphate, inulin and yellow iron oxide (E172 - capsule colouring agent)
Other: Placebo
Matching capsule without active plant extracts, administered twice daily three capsules (in total six), 30-60 minutes before main meals, for 12 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
GLP-1 secretion
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks changes GLP-1 secretion (area under the curve (AUC) over 60 minutes) in overweight or obese subjects* compared to the start of the study (AUC over 60 minutes).
12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intervention vs. Placebo
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks changes GLP-1, DPP-4, GIP, and insulin secretion (AUC over 60 min) in overweight or obese subjects* compared to taking a placebo (AUC over 60 min).
12 weeks
Liquid Meal
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks changes GLP-1, DPP-4, GIP, and insulin secretion (AUC over 60 min) in overweight or obese subjects* after consuming a standardised liquid meal compared to intake at the start of the study (AUC over 60 min).
12 weeks
Liquid Meal: Intervention vs. Placebo
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks changes GLP-1, DPP-4, GIP, and insulin secretion (AUC over 60 min) in overweight or obese subjects* after consuming a standardised liquid meal compared to taking a placebo (AUC over 60 min).
12 weeks
Body weight
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks leads to changes in body weight (kg).
12 weeks
Body mass index (BMI) in kg/m²
Time Frame: 12 weeks
BMI in kg/m² will be determined using weight (kg) and height (m). Taking the dietary supplement over a period of 12 weeks leads to changes in BMI.
12 weeks
Abdominal Circumference
Time Frame: 12 weeks
Taking the dietary supplement over a period of 12 weeks leads to changes in the abdominal circumference (cm).
12 weeks
Waist to Hip Ratio
Time Frame: 12 weeks
Taking the dietary supplement leads to changes in the waist-hip ratio (cm waist/cm hip = WHR).
12 weeks
Changes in Control of Eating Questionnaire (CoEQ)
Time Frame: 12 weeks
Participants report on their control of eating by answering the Control of Eating Questionnaire (CoEQ) with 19 questions. Rating on a horizontal, non-calibrated line of 10 cm, ranging from very low (0) to very high (10).
12 weeks
Visual analog scale (VAS) to assess hunger
Time Frame: 12 weeks
Visual analog scale (VAS) to assess hunger on a horizontal, non-calibrated line of 10 cm, ranging from not hungry at all (0) to very hungry (10)
12 weeks
Visual analog scale (VAS) to assess satiation
Time Frame: 12 weeks
Visual analog scale (VAS) to assess satiation (process that leads to the termination of eating) on a horizontal, non-calibrated line of 10 cm, ranging from completely empty (0) to cannot eat another bite (10)
12 weeks
Visual analog scale (VAS) to assess desire to eat
Time Frame: 12 weeks
Visual analog scale to assess desire to eat on a horizontal, non-calibrated line of 10 cm, ranging from very low (0) to very strong (10)
12 weeks
Visual analog scale (VAS) to assess the amount that can be eaten right now
Time Frame: 12 weeks
Visual analog scale to assess the amount that can be eaten right now on a horizontal, non-calibrated line of 10 cm, ranging from not at all (0) to a large amount (10)
12 weeks
Visual analog scale (VAS) to assess satiety
Time Frame: 12 weeks
Visual analog scale to assess satiety (feeling of fullness that persists after eating suppressing further energy intake) on a horizontal, non-calibrated line of 10 cm, ranging from not full at all (0) to totally full (10)
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

FFoQSI - Austrian Competence Centre for Feed and Food Quality, Safety & Innovation

Collaborators

University of Applied Sciences Upper Austria
Salzburger Universitätsklinkum

Investigators

  • Study Director: Daniel Weghuber, Prim. Univ. Prof. Dr., Salzburger Universitätsklinikum

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 24, 2025

Primary Completion (Actual)

March 11, 2026

Study Completion (Estimated)

May 11, 2026

Study Registration Dates

First Submitted

September 24, 2025

First Submitted That Met QC Criteria

November 16, 2025

First Posted (Actual)

November 20, 2025

Study Record Updates

Last Update Posted (Actual)

March 30, 2026

Last Update Submitted That Met QC Criteria

March 27, 2026

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1098/2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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