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NCT Number: NCT07303543

Preventing Muscle Loss After Bariatric Surgery: Protein-Collagen Supplementation and Resistance Exercise

The aim of this clinical trial is to investigate the effectiveness of collagen, considered a new approach to prevent muscle mass loss after bariatric surgery, and to demonstrate the relationship between this effect and exercise. The key questions it aims to answer are:

Does whey protein supplementation with collagen combined with resistance exercise prevent muscle mass loss after bariatric surgery? Do whey protein supplementation with collagen combined with resistance exercise affect fat mass after bariatric surgery?

Researchers will compare collagen with whey protein.

The study groups and interventions to be implemented are summarized below:

Group 1: Control Group (CG; n: 10) Whey protein supplementation will be administered Vitamin and mineral supplementation will be administered No resistance exercise will be performed The participants will eat according to bariatric surgery nutrition guidelines and perform physical activities.

Group 2: Whey Protein + Collagen + Exercise Group (WPCEG; n: 10) Whey protein supplements with collagen will be given. Vitamin and mineral supplements will be given. Resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

They will begin a resistance exercise program 4 weeks after surgery.

Group 3: Whey Protein + Collagen + No Exercise Group (WPCG; n: 10) Whey protein supplements with collagen will be given. Vitamin and mineral supplements will be given. No resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

Group 4: Whey Protein + Exercise Group (WPEG; n: 10) Whey protein supplements will be given. Vitamin and mineral supplements will be given. Resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

A resistance exercise program will begin at 4 weeks post-operatively.

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Key information

Conditions

Bariatric Surgery Atrophy Muscle Loss Muscular Atrophy Nervous System Diseases Neurologic Manifestations Neuromuscular Manifestations Pathological Conditions, Anatomical Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

20 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Istanbul Medipol University

Istanbul, Fatih, Turkey (Türkiye)

Location status: Recruiting

Location contact

Rüken A Samancı, Msc

CONTACT

[email protected]

+90 543 939 15 94

About this study

Bariatric surgery is an effective method for treating obesity, but a significant decrease in skeletal muscle mass can be observed in the early postoperative period. This loss of muscle mass can negatively affect physical functions, reduce metabolic rate, and make long-term weight maintenance more difficult. Therefore, developing strategies to prevent muscle loss after bariatric surgery is of great clinical importance.

The use of whey protein to support muscle protein synthesis in the postoperative period is a common practice. In recent years, there has been increased scientific interest in the potential of collagen peptides, especially when used in conjunction with resistance exercise, to contribute to muscle mass preservation. However, studies evaluating the combined effect of collagen supplementation and exercise programs in addition to whey protein in individuals undergoing bariatric surgery are limited.

This clinical study aims to investigate the effectiveness of adding collagen to standard whey protein supplementation and a resistance exercise program in preventing muscle loss. Four different groups will be designed to evaluate the independent and combined effects of collagen and exercise:

  • Group receiving only whey protein,
  • Whey + collagen + exercise group,
  • Whey + collagen but no exercise group,
  • Whey + exercise but no collagen group.

All participants will follow a standard post-bariatric surgery nutrition protocol and receive routine vitamin and mineral supplements. The resistance exercise program will begin four weeks after surgery; it will consist of progressively more intense, supervised exercises targeting large muscle groups. Body composition assessments will be performed at baseline and at specified follow-up weeks. The primary outcome measure is change in skeletal muscle mass; secondary outcome measures are fat mass, functional capacity, and exercise compliance.

This study is expected to contribute to the identification of optimal nutrition and exercise strategies to reduce muscle loss after bariatric surgery.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Being between 20-50 years old
  • Body mass index; 35 ≤ BMI< 60 kg/m2
  • Not being pregnant
  • Not being addicted to alcohol and drugs
  • Not having entered menopause
  • No exercise restrictions

Exclusion criteria

  • Having at least one of the following inflammatory bowel diseases, upper gastrointestinal bleeding, advanced psychiatric diseases, cancer, and kidney failure.
  • using statins
  • be pregnant
  • Being addicted to alcohol and drugs
  • to have entered menopause
  • Having exercise restrictions
  • Becoming a professional athlete
  • Having done more than 60 minutes of regular and structured exercise per week in the last year

Treatment and study plan

Whey Protein Supplement

Dietary Supplement

Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.

Hydrolyzed Collagen Supplement

Dietary Supplement

Oral hydrolyzed collagen supplement provided daily in combination with whey protein.

Vitamin and Mineral Supplementation

Dietary Supplement

Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.

Resistance exercise program

Behavioral

Structured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week.

Primary outcomes

  1. Change in Skeletal Muscle Mass (kg) Measured by BIA

    Time frame: Baseline (preoperative), postoperative week 4 (day 29), and postoperative week 12 (day 85)

    Skeletal muscle mass (kg) will be measured using a multi-frequency bioelectrical impedance analysis (BIA) device. The outcome will be reported as the mean change from baseline at each time point in each study group.

Secondary outcomes

  1. Change in Fat Mass (kg) Measured by BIA

    Time frame: Baseline, week 4, and week 12

    Fat mass (kg) will be measured using BIA. Results will be summarized as the mean change from baseline for each group.

Study contacts

Contact information is provided by the study sponsor or research team.

Rüken A Samancı, Msc

CONTACT

[email protected]

+90 543 939 15 94

Sponsors and collaborators

Lead sponsor

Medipol University

Other

Registry information

Official study title

Preventing Muscle Loss in the Early Postoperative Period of Bariatric Surgery With a Combination of Whey Protein, Hydrolyzed Collagen, and Resistance Exercise: A Prospective, Randomized, Controlled Clinical Study

Important dates

Study start
2022
Primary completion
2025
Study completion
2026
First posted
Dec 26, 2025
Registry last updated
Dec 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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