Bariatric SurgeryNCT07303543
Preventing Muscle Loss After Bariatric Surgery: Protein-Collagen Supplementation and Resistance Exercise
A study testing Whey protein supplement, Hydrolyzed Collagen Supplement and Vitamin and Mineral Supplementation in people with Bariatric Surgery and Muscle Loss, run by Medipol University at 1 site in Turkey (Türkiye).
Trial summary
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. Read more about this study
- Who is it for?
- Ages 20 to 50 years
- Conditions the study is for
- Bariatric Surgery, Muscle Loss
- What is being tested?
- Whey protein supplement, Hydrolyzed Collagen Supplement and Vitamin and Mineral Supplementation
- Type of treatment
- Pill or oral medicine, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 35 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 2 Aug 2022to 30 Jan 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Istanbul Medipol University
Istanbul, Fatih
Rüken A Samancı, Msc, +90 543 939 15 94, rasamanci@medipol.edu.tr
About this study
Official 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
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?
Read more
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.
Read the detailed description
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.
- Conditions
- Bariatric Surgery, Muscle Loss
- Being tested
- Whey protein supplement, Hydrolyzed Collagen Supplement, Vitamin and Mineral Supplementation, Resistance Exercise Program
- Keywords
- Bariatric Surgery, Collagen, Resistance exercise, Whey protein, Muscle loss
- Medical subject headings
- Muscular Atrophy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Whey protein supplementDietary supplement
Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.
Hydrolyzed Collagen SupplementDietary supplement
Oral hydrolyzed collagen supplement provided daily in combination with whey protein.
Vitamin and Mineral SupplementationDietary supplement
Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.
Resistance Exercise ProgramBehavioural
Structured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week.
| Study group | Role | What they receive |
|---|---|---|
| Control Group (CG) | Active comparator | Whey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercise will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their regular physical activities.
A comparison will be made with the other groups as the control group. Receives: Dietary Supplement: Whey protein supplement; Dietary Supplement: Vitamin and Mineral Supplementation |
| Whey Protein + Collagen + Exercise Group (WPCEG) | Experimental | Collagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities.
They will begin the resistance exercise program in the 4th week after surgery. Receives: Dietary Supplement: Whey protein supplement; Dietary Supplement: Hydrolyzed Collagen Supplement; Dietary Supplement: Vitamin and Mineral Supplementation; Behavioral: Resistance Exercise Program |
| Whey Protein + Collagen + Non-Exercise Group (WPCG) | Experimental | Collagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. Receives: Dietary Supplement: Whey protein supplement; Dietary Supplement: Vitamin and Mineral Supplementation |
| Whey Protein + Exercise Group (WPEG) | Experimental | Whey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities.
They will begin the resistance exercise program in the 4th week after surgery. Receives: Dietary Supplement: Whey protein supplement; Dietary Supplement: Vitamin and Mineral Supplementation; Behavioral: Resistance Exercise Program |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Skeletal Muscle Mass (kg) Measured by BIA
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.
Measured: Baseline (preoperative), postoperative week 4 (day 29), and postoperative week 12 (day 85)
Secondary outcomes (1)
Change in Fat Mass (kg) Measured by BIA
Fat mass (kg) will be measured using BIA. Results will be summarized as the mean change from baseline for each group.
Measured: Baseline, week 4, and week 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Dec 2025
- Study start2 Aug 2022
- Primary completion20 Dec 2025 (estimated)
- Study completion30 Jan 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Bariatric SurgeryStudies of the same condition, open and under way.
- More trials run by Medipol UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 35 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medipol University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Rüken Aslınur Samanci, Medipol University
- Investigators
- Halit E Taşkın, Dr., Principal investigator, Cerrahpaşa Faculty of Medicine, General SurgeryNihal Z Erdem, PhD, Principal investigator, Istanbul Medipol University, Nutrition and DieteticsBürke Köksalan, PhD, Principal investigator
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07303543
- Sponsor's protocol ID
- E-66291034-772.02-3053
- Status last verified
- Dec 2025
- First submitted
- 17 Nov 2025
- Last updated
- 26 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because this study involves identifiable clinical and nutritional data collected at a single center, and participant privacy cannot be fully ensured despite anonymization
Study at a glance
From the registry record, last updated by the sponsor on 26 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official 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
- ClinicalTrials.gov ID
- NCT07303543
- Acronym / sponsor ID
- E-66291034-772.02-3053
- Conditions
- Bariatric Surgery, Muscle Loss
- Keywords
- Bariatric Surgery, Collagen, Resistance exercise, Whey protein, Muscle loss
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 35 participants (estimated)
- Lead sponsor
- Medipol UniversityUniversity, hospital or other
- Study start
- 2 Aug 2022 (actual)
- Primary completion
- 20 Dec 2025 (estimated)
- Study completion
- 30 Jan 2026 (estimated)
- First posted
- 26 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Control Group (CG) | Active comparator | Dietary Supplement: Whey protein supplement, Dietary Supplement: Vitamin and Mineral SupplementationWhey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercise will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their regular physical activities. A comparison will be made with the other groups as the control group. |
| Whey Protein + Collagen + Exercise Group (WPCEG) | Experimental | Dietary Supplement: Whey protein supplement, Dietary Supplement: Hydrolyzed Collagen Supplement, Dietary Supplement: Vitamin and Mineral Supplementation, Behavioral: Resistance Exercise ProgramCollagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. They will begin the resistance exercise program in the 4th week after surgery. |
| Whey Protein + Collagen + Non-Exercise Group (WPCG) | Experimental | Dietary Supplement: Whey protein supplement, Dietary Supplement: Vitamin and Mineral SupplementationCollagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. |
| Whey Protein + Exercise Group (WPEG) | Experimental | Dietary Supplement: Whey protein supplement, Dietary Supplement: Vitamin and Mineral Supplementation, Behavioral: Resistance Exercise ProgramWhey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. They will begin the resistance exercise program in the 4th week after surgery. |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (8 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Whey protein supplementOral whey protein supplement provided daily according to bariatric surgery nutrition protocol. | Dietary supplement | Control Group (CG), Whey Protein + Collagen + Exercise Group (WPCEG), Whey Protein + Collagen + Non-Exercise Group (WPCG), Whey Protein + Exercise Group (WPEG) |
| Hydrolyzed Collagen SupplementOral hydrolyzed collagen supplement provided daily in combination with whey protein. | Dietary supplement | Whey Protein + Collagen + Exercise Group (WPCEG) |
| Vitamin and Mineral SupplementationRoutine vitamin and mineral supplementation according to bariatric surgery follow-up protocol. | Dietary supplement | Control Group (CG), Whey Protein + Collagen + Exercise Group (WPCEG), Whey Protein + Collagen + Non-Exercise Group (WPCG), Whey Protein + Exercise Group (WPEG) |
| Resistance Exercise ProgramStructured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week. | Behavioural | Whey Protein + Collagen + Exercise Group (WPCEG), Whey Protein + Exercise Group (WPEG) |
Primary outcome
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.
1 secondary outcome
Change in Fat Mass (kg) Measured by BIA
Time frame: Baseline, week 4, and week 12
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Dec 2025.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because this study involves identifiable clinical and nutritional data collected at a single center, and participant privacy cannot be fully ensured despite anonymization
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Halit E Taşkın, Dr. principal investigator
Cerrahpaşa Faculty of Medicine, General Surgery
Nihal Z Erdem, PhD principal investigator
Istanbul Medipol University, Nutrition and Dietetics
Bürke Köksalan, PhD principal investigator
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Whey protein supplement, Hydrolyzed Collagen Supplement and Vitamin and Mineral Supplementation in people with Bariatric Surgery and Muscle Loss, run by Medipol University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 26 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Rüken A Samancı, Msc (+90 543 939 15 94, rasamanci@medipol.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Skeletal Muscle Mass (kg) Measured by BIA (time frame: Baseline (preoperative), postoperative week 4 (day 29), and postoperative week 12 (day 85)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Dec 2025; AzTrials last refreshed its copy on 8 Nov 2026.