Millions of people are losing weight using GLP-1 drugs, but the medications are having unexpected impacts on their romantic relationships. Prescribing doctors often warn of side-effects such as nausea and vomiting, but the effects on love lives are less understood.
Jennifer's story: Weight loss reveals deeper issues
Jennifer, a 57-year-old litigation attorney who asked to keep her surname private, had struggled with obesity since childhood. She underwent gastric sleeve surgery in her 30s but regained the weight. In 2023, she started taking Mounjaro, a GLP-1 medication. Three years later, she is 40kg (88lb) lighter. But the drug has brought unexpected fallout to her 30-year marriage.
Her husband had concerns about side-effects but agreed it was worth trying. Now, after her weight loss, he suggested couples therapy because Jennifer did not 'magically become more physically demonstrative in the bedroom' and commented she had become 'meaner.' Jennifer says: 'I'm less afraid of our relationship failing, so maybe I hold him to a higher standard than I used to.' Without her obesity to blame, she realises her marital problems were 'always a two-person problem.'
Potential mechanisms and mixed evidence
Dr Terri-Lynne South, a GP specialising in obesity medicine, notes that GLP-1s may affect dopamine reward pathways, reducing pleasure-seeking around alcohol, nicotine, and potentially sex drives. But evidence on sexual function is limited and mixed. Some studies suggest improved testosterone levels; a 2025 FDA analysis found 185 reports of sexual dysfunction, especially in men. A 2025 Kinsey study showed 18% of respondents reported increased sexual desire on GLP-1s while 16% reported decreased desire.
Dr Mark Mellor, a bariatric doctor, says: 'Human libido and relationships are complex at their core, so it would be very difficult to extrapolate what it is about these medicines specifically.'
Relationship disruption and new dynamics
Glenn Mackintosh, a psychologist specialising in weight management, says couples often mention disruption to shared routines, like finishing the day with Netflix and chips. 'It can really cause friction. What we often say is that weight loss doesn't cause relationship problems but it can reveal them.'
For some, renewed confidence can lead to new relationships. Joanna Wood, a former Australian diplomat, lost 25kg taking a GLP-1 and started dating again after 14 years of singledom. She felt shame about using the drug, but her partner Bruce Hart, a social worker, did not mind. 'To me, it was such a background issue,' Hart says.
Dr Rebecca Puhl, a psychologist studying weight stigma, says people sometimes hide GLP-1 use: 'They’re worried that they’ll be viewed as cheating or lacking willpower by a potential partner.' Wood briefly stopped the medication, regained 10kg, and found herself hiding confectionery from Hart. She has since restarted, accepting lifelong treatment.
Uncertain futures
Jennifer remains on a GLP-1 and expects to be for life. Her marriage is stable for now but unresolved: 'We will adapt in some way – I am just not sure how yet.'
