Experts have identified why weight-loss injections such as Mounjaro and Wegovy may cause a drop in sex drive. The drugs, originally developed for diabetes, work by mimicking the hormone GLP-1 to suppress appetite, but they also appear to dampen dopamine-driven reward signals that influence libido.
Dr Ryan Sultan, assistant professor of clinical psychiatry at Columbia University, told Medscape: 'Sex is based on drive and reward as well, and many neuronal networks involved in food and sex drives overlap. When we take GLP-1s, we are essentially dampening the internal processes that drive us to address our evolutionary needs.'
Dr Bronwyn Holmes, a hormone specialist at US weight loss clinic Eden, added: 'These drugs are thought to dampen dopamine-driven reward signals, which help reduce the cravings for food and other compulsive behaviors. This can indirectly affect mood and motivation, useful for weight loss but potentially relevant to other reward-driven activities like intimacy.'
A British study published last year in QJM: An International Journal of Medicine found that new patients on the drug may experience cognitive changes in decision-making, partly due to calorie deficit and the effects of GLP-1 on brain function. However, no large-scale studies have determined how common these side effects are or which groups are most affected.
At least half a million NHS patients and 15 million US patients are now using weight-loss jabs. The warning comes amid a reported global decline in sexual activity, with a survey showing 27 per cent of Britons having less sex than before.
