Clinical trial Recruiting at 1 site Interventional Ages 18 to 70

Investigating gut hormones after gastric bypass surgery

Official title: Do Gut Hormones Mediate the Beneficial Effects of Roux-en-Y Bypass?

Run by Imperial College London · NCT01945840 · Data updated 2026-11-12

This study is testing how certain gut hormones change after gastric bypass surgery to see if they help with weight loss and managing blood sugar in people with obesity and type 2 diabetes.

Quick facts

Study typeInterventional
Ages18 Years to 70 Years
SexAll
Enrollment190 (estimated)
SponsorImperial College London
Academic / other
Locations1 site (London, Greater London)
StatusRecruiting
StartedOctober 2013
Main results expectedOctober 31, 2028
Study endsOctober 31, 2028
Registry record updatedApril 20, 2021
Trial IDNCT01945840 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates include adults aged 18-70 with impaired glucose regulation or type 2 diabetes who are eligible for bariatric surgery.

Probably not a fit

Patients with a history of medical or psychological conditions that could interfere with the study or those who are pregnant or breastfeeding may not benefit.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This study aims to explore the role of gut hormones in the metabolic benefits observed after Roux-en-Y gastric bypass surgery. It will assess the chronic elevation of hormones such as GLP-1, oxyntomodulin, and PYY, and their impact on glycaemia, energy expenditure, food intake, and weight loss. Participants will undergo surgery, receive gut hormone infusions, and follow a very low-calorie diet to evaluate these effects. The study seeks to clarify the mechanisms behind the surgery's effectiveness in treating obesity and type 2 diabetes.

Why it matters

Potential benefit: If successful, this study could lead to improved treatment strategies for obesity and type 2 diabetes through better understanding of gut hormones.

How similar studies have gone: Other studies have shown promising results in understanding the role of gut hormones in metabolic changes post-surgery, indicating this approach has potential.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion criteria

* Aged 18 - 70 years.
* Male or female.
* Eligible for bariatric surgery under the NHS.
* Diagnosed with impaired glucose regulation or type 2 diabetes, according to WHO 2011 criteria.
* Those with diabetes should be stable and well controlled with either diet or one oral hypoglycaemic agent.
* HbA1c ≤9.0% or 74.9 mmol/mol.

Exclusion criteria

* History of any medical, psychological or other condition, or use of any medications, including over-the-counter products, which, in the opinion of the investigators, would either interfere with the study or potentially cause harm to the volunteer.
* Without access at home to a telephone or other factor likely to interfere with ability to participate reliably in the study.
* Pregnancy or breastfeeding.
* Smokers.
* Unable to maintain adequate contraception for the duration of the study and for one month afterwards.
* History of hypersensitivity to any of the components of the subcutaneous infusions.
* Donated blood during the preceding 3 months or intention to do so before the end of the study.
* Insulin treatment.
* Uncontrolled hypertension.
* Any other co-morbidity that would compromise the validity of the study or the safety of the participant such as heart failure, clinically apparent cardiovascular disease.
* Volunteers on anti-coagulants such as warfarin and factor Xa inhibitors will not undergo adipose tissue biopsy.
* Unable to give informed consent.
* Previous bariatric surgery.
* Unable to undergo fMRI due to:

  * Claustrophobia.
  * Pacemaker, metal implant, clips, implanted device, shrapnel or bullet, metal in eyes that precludes magnetic resonance imaging.
  * Significant structural abnormality on magnetic resonance brain scan

Where it's running

  • NIHR/Wellcome Trust Imperial CRF, Hammersmith Hospital
    London, Greater London, United Kingdom
    Recruiting

Study contacts

  • Principal investigator: Stephen R Bloom, FRS FRCP MD — Imperial College London
  • Study coordinator: Tricia Tan, MBChB MRCP
  • Email: t.tan@imperial.ac.uk

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.