Off-label GLP-1 weight-loss medicine use among online bodybuilders: Folk pharmacology, risk and harm reduction

GLP-1 medicines (e.g. Semaglutide; Tirzepatide) are diabetes medicines that have recently been approved for weight loss purposes. These drugs are increasingly common, with many users accessing these medicines for off-label lifestyle-oriented purposes. While recent research has explored increased interest in these drugs, to date no studies have explored their use in bodybuilding cultures. With bodybuilders often at the forefront of experimental drug use, and diffusing knowledge of drugs to other populations, this research examines bodybuilders' understandings of use and risk of GLP-1 medicines, and community approaches to harm reduction. This research adopted a netnographic approach, exploring 12,392 unique posts from 160 threads across two popular bodybuilding forums. Qualitative thematic analysis of posts was undertaken. Bodybuilders frequently undertook experimental approaches to GLP use, including 'stacking' multiple compounds and 'cycling' between them, presenting risk. GLPs' utility for bodybuilding was questioned by some owing to their muscle-wastage effects, but many bodybuilders combined them with anabolic-androgenic steroids (AAS) to off-set these side-effects. In addition to their weight-loss properties, many users discussed the drugs' anti-ageing properties, and older men appear to be a significant emerging user population. While displacing potentially dangerous fat burners in bodybuilders' folk pharmacologies, GLPs nonetheless presented risks of hypoglycaemia when combined with AAS, and broader harms. Harm reduction information was frequently shared in forum spaces as part of bodybuilders' communal folk pharmacology, but some enabling behaviours likely to heighten risk were also identified. We examine the likely implications of these findings for public health, with particular reference to the practices of 'cycling' and 'stacking' GLP medicines and the risk this presents, particularly when combined with drugs such as AAS and far burners. We discuss the need for harm reduction services such as drug testing services, and the need for healthcare professionals to be aware of anti-ageing motivations for use among older men. Continued research into novel GLP use is needed.