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NCT Number: NCT07809152

Collagen Supplements and Post-MBS Muscle Mass/Body Image

This prospective, observational cohort study aims to evaluate whether the use of collagen-containing supplements is associated with differences in muscle mass, body composition, and body image among patients who have undergone sleeve gastrectomy (SG). The study will be conducted at the General Surgery outpatient clinic of a private hospital in Bursa, Türkiye, between May 2026 and March 2027, and will enroll adult patients (aged 18-65 years) who meet current ASMBS/IFSO eligibility criteria for metabolic and bariatric surgery.

Participants will be naturally allocated into two observational groups based on their own choice to use or not use collagen-containing supplements; no supplement will be provided or recommended by the study team, and no intervention will be made to participants' standard clinical care. All patients will be followed according to routine clinical practice preoperatively and at 2 weeks, 1 month, 3 months, and 6 months postoperatively.

Primary outcome measures include anthropometric parameters (body weight, BMI, fat mass, fat mass percentage, fat-free mass, muscle mass, percentage of weight loss, percentage of excess weight loss, waist and hip circumference) assessed via bioelectrical impedance analysis (Tanita MC-780 MA), and body image assessed using the Turkish-validated Body Shape Questionnaire (BSQ). Secondary outcomes include biochemical parameters, comorbidities, and macronutrient intake data obtained from 3-day dietary records analyzed using the BEBİS nutrition software.

The study hypothesizes that patients using collagen-containing supplements will show significant differences in muscle mass and body composition parameters compared with non-users, and that supplement use will be significantly associated with BSQ scores. A sample size of approximately 52 participants per group was calculated using G*Power 3.1 (one-way ANOVA, Cohen's f = 0.25, α = 0.05, power = 0.80).

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Key information

Conditions

Obesity & Overweight Bariatric Surgery Body Composition Body Image Body Weight Collagen Protein Metabolic and Bariatric Surgery Muscle Composition Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Yıldırım Doruk Hastanesi

Bursa, Yıldırım, Turkey (Türkiye)

Location status: Recruiting

Location contact

CONTACT

[email protected]

05393919700

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Patients with a BMI ≥ 35 kg/m², regardless of the presence of comorbidities
  • Patients with a BMI of 30-34.9 kg/m² who have an obesity-related metabolic disease and are considered eligible for surgical treatment
  • Patients who have undergone metabolic and bariatric surgery (MBS) in accordance with current ASMBS/IFSO guidelines (Eisenberg et al., 2022)
  • Patients under regular postoperative follow-up
  • Age 18-65 years

Exclusion criteria

  • Inflammatory bowel disease
  • History of upper gastrointestinal bleeding
  • Severe psychiatric disorders
  • Active cancer diagnosis
  • Pregnancy or breastfeeding
  • Alcohol or substance dependence
  • Physical limitations preventing participation in exercise

Treatment and study plan

Collagen-containing supplement

Dietary Supplement

Collagen-containing supplement products used at the participants' own discretion following sleeve gastrectomy. The type of product, daily dosage, and duration of use were self-reported by participants

Primary outcomes

  1. Change in Body Weight

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    Body weight (kg) measured using a Tanita MC-780 MA device.

  2. Change in Body Shape Questionnaire (BSQ) Score

    Time frame: Preoperative and postoperative 6 months

    Body image concerns were assessed using the Body Shape Questionnaire (BSQ-34), a validated instrument for the Turkish population. This 34-item self-report scale evaluates weight-related concerns and dissatisfaction with body shape over the preceding four weeks. Each item is scored from 1 (never) to 6 (always), with a total score range of 34 to 204. Higher scores indicate greater dissatisfaction with body shape, i.e., a worse outcome.

  3. Change in Body Mass Index (BMI)

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    BMI calculated as body weight (kg) divided by height squared (m²).

  4. Percentage of Total Weight Loss (%TWL)

    Time frame: Postoperative and 6 months

    Calculated as (preoperative weight - postoperative weight) / preoperative weight × 100.

  5. Percentage of Excess Weight Loss (%EWL)

    Time frame: Postoperative and 6 months

    Calculated as (preoperative weight - postoperative weight) / (preoperative weight - ideal weight) × 100. Ideal body weight was calculated assuming a BMI of 25 kg/m².

  6. Change in Fat Mass

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    Fat mass (kg) assessed by multi-frequency bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  7. Change in Fat Mass Percentage

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    Fat mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  8. Change in Muscle Mass

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    Muscle mass (kg) assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  9. Change in Muscle Mass Percentage

    Time frame: Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

    Muscle mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

Secondary outcomes

  1. Change in Fasting Blood Glucose

    Time frame: Preoperative and 6 months

    Fasting blood glucose (mg/dL) obtained from routine clinical laboratory follow-up.

  2. Change in Fasting Insulin

    Time frame: Preoperative and 6 months

    Fasting insulin (µIU/mL) obtained from routine clinical laboratory follow-up.

  3. Change in HbA1c

    Time frame: Preoperative and 6 months

    Glycated hemoglobin (HbA1c, %) obtained from routine clinical laboratory follow-up.

  4. Change in LDL Cholesterol

    Time frame: Preoperative and 6 months

    LDL cholesterol (mg/dL) obtained from routine clinical laboratory follow-up.

  5. Change in HDL Cholesterol

    Time frame: Preoperative and 6 months

    HDL cholesterol (mg/dL) obtained from routine clinical laboratory follow-up.

  6. Change in Triglycerides

    Time frame: Preoperative and postoperative 6 months

    Triglycerides (mg/dL) obtained from routine clinical laboratory follow-up.

  7. Change in Total Cholesterol

    Time frame: Preoperative and postoperative 6 months

    Total cholesterol (mg/dL) obtained from routine clinical laboratory follow-up.

  8. Change in ALT

    Time frame: Preoperative and 6 months

    Alanine aminotransferase (ALT, U/L) obtained from routine clinical laboratory follow-up.

  9. Change in AST

    Time frame: Preoperative and 6 months

    Aspartate aminotransferase (AST, U/L) obtained from routine clinical laboratory follow-up.

  10. Change in Uric Acid

    Time frame: Preoperative and 6 months

    Uric acid (mg/dL) obtained from routine clinical laboratory follow-up.

  11. Change in Urea

    Time frame: Preoperative and 6 months

    Urea (mg/dL) obtained from routine clinical laboratory follow-up.

  12. Change in Hemoglobin

    Time frame: Preoperative and 6 months

    Hemoglobin (g/dL) obtained from routine clinical laboratory follow-up.

  13. Change in Hematocrit

    Time frame: Preoperative and 6 months

    Hematocrit (%) obtained from routine clinical laboratory follow-up.

  14. Change in Ferritin

    Time frame: Preoperative and 6 months

    Ferritin (ng/mL) obtained from routine clinical laboratory follow-up.

  15. Change in Serum Iron

    Time frame: Preoperative and 6 months

    Serum iron (µg/dL) obtained from routine clinical laboratory follow-up.

  16. Change in Vitamin B12

    Time frame: Preoperative and 6 months

    Vitamin B12 (pg/mL) obtained from routine clinical laboratory follow-up.

  17. Change in Folic Acid

    Time frame: Preoperative and 6 months

    Folic acid (ng/mL) obtained from routine clinical laboratory follow-up.

  18. Change in Magnesium

    Time frame: Preoperative and 6 months

    Magnesium (mg/dL) obtained from routine clinical laboratory follow-up.

  19. Change in Total Calcium

    Time frame: Preoperative and 6 months

    Total calcium (mg/dL) obtained from routine clinical laboratory follow-up.

  20. Change in Serum Sodium

    Time frame: Preoperative and 6 months

    Serum sodium (mEq/L) obtained from routine clinical laboratory follow-up.

  21. Change in Serum Potassium

    Time frame: Preoperative and 6 months

    Serum potassium (mEq/L) obtained from routine clinical laboratory follow-up.

Study contacts

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

Emre Şen, Master's degree graduate

CONTACT

0 532 163 30 87

Seher Şen, Assistant Professor

CONTACT

[email protected]

+905393919700

Sponsors and collaborators

Lead sponsor

Mudanya University

Other

Registry information

Official study title

Relationship Between Collagen-Containing Supplement Use and Muscle Mass and Body Image Following Metabolic and Bariatric Surgery: A Prospective Observational Study

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Sep 9, 2026
Registry last updated
Sep 9, 2026

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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