FULLY FUNDED PhD - PREservation of muscle Size and Strength during GLP-1RA therapy with Krill Oil (PRESS-KO)

Project Description

Obesity and type 2 diabetes represent major global health challenges, with rising prevalence and substantial societal and economic burden. While recently developed pharmacological therapies such as glucagon-like peptide-1 receptor agonists (GLP-1RAs), including semaglutide and tirzepatide, have revolutionised the treatment of obesity through significant weight loss and improved glycaemic control, these benefits come with an important limitation: a substantial proportion of weight lost (20–50%) is derived from lean tissue, including skeletal muscle. Preservation of muscle mass and strength is critical, given its importance for physical function, metabolic health, and prevention of conditions such as sarcopenia, which is associated with increased risk of falls, frailty, and reduced quality of life.

This PhD project aims to investigate a novel, practical nutritional strategy to mitigate muscle loss during GLP-1RA-induced weight loss. Specifically, the project will determine whether supplementation with krill oil, a rich source of long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA), can preserve muscle mass and strength in individuals with overweight or obesity initiating GLP-1RA therapy.

Preliminary work from our group provides strong rationale for this approach. In healthy older adults, krill oil supplementation significantly improved muscle strength, grip strength, and muscle thickness, with additional evidence for enhanced neuromuscular function. Furthermore, pilot data in individuals undergoing dietary weight loss demonstrate that krill oil attenuates losses in fat-free mass and strength, while improving physical function and cardiovascular markers. However, these findings have not yet been tested in the context of pharmacologically induced weight loss using GLP-1RAs, where muscle loss may be more pronounced.

To address this, we will conduct a double-blind, randomised controlled trial in adults with overweight or obesity initiating GLP-1RA therapy (semaglutide or tirzepatide). Participants will be randomised to receive either krill oil (4 g/day) or placebo for 18 weeks. The primary outcome will be knee extensor muscle strength, with secondary outcomes including muscle size, physical function, insulin sensitivity, blood pressure, appetite, and detailed neuromuscular function.

The project will use a comprehensive, state-of-the-art assessment approach, combining imaging (ultrasound), functional testing (gait analysis, timed mobility tasks), metabolic testing (oral glucose tolerance test), and advanced neuromuscular techniques including electromyography and transcranial magnetic stimulation. This will allow not only evaluation of clinical outcomes but also mechanistic insight into how krill oil may influence muscle preservation, including effects on motor unit behaviour and neural control of muscle.

This PhD offers interdisciplinary training across clinical trials, human physiology, nutrition, and neuromuscular biology, alongside experience in advanced analytical techniques and data analysis. It would be highly suitable for students with a background, for example, in nutrition, exercise science or neuroscience. The student would work with the supervisory team of Professor Stuart Gray and Dr James Boyle, as well as the wider research group.

Project start date: October 2026.