Study summary
As people get older, they naturally lose muscle mass and strength. This age-related muscle loss can make everyday activities, such as climbing stairs or carrying shopping, more difficult and may reduce independence. Researchers believe this decline may be partly linked to lower levels of a substance in the body called NAD+, which helps cells produce energy. Understanding whether boosting NAD+ levels can improve muscle health is important for supporting healthy ageing.
This study will investigate whether a form of vitamin B3, called nicotinamide riboside (NR), can improve muscle health in older men. We now know that taking an NR supplement can boost the NAD+ levels in our blood and muscle. Participants will be randomly assigned to take either NR or a placebo (a look-alike capsule with no active ingredient) for nine weeks. Neither participants nor researchers will know which treatment is being taken until the study ends, ensuring fair and accurate results. Before and after the 9 weeks of taking either the NR or the lookalike (placebo) supplement participants will attend the laboratory where basic muscle function will determine and a full body MRI scan well be completed. Participants will also complete 1 session of strength type (weightlifting) exercise (focused only on the legs) before and after the supplementation to understand if taking NR is able to improve how the body responds to exercise.
Blood and muscle samples will be taken throughout the study; participants will provide six blood samples and undergo four muscle biopsies (small samples of muscle tissue taken from the outside part of the thigh under local anaesthetic). Blood and muscle samples will allow us to measure NAD+ levels, markers of muscle health, and how muscles respond to exercise. These measurements will help determine whether NR improves muscle function and cellular energy production.