Why GLP-1 drugs fail for up to a third of patients — SkimNews
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- Clinical trials show between 9% and a third of participants on GLP-1 medications lose less than 5% of their body weight, depending on the drug and dose, yet the reason remains unclear.
- Mercedes, a recently retired Canadian teacher, cycled through Ozempic, Wegovy, Contrave, Mounjaro and Zepbound over more than a year and saw no weight loss, describing cravings 'like heroin withdrawal' even when she strictly limited food.
- Yury K, 57, who exercises five days a week and avoids fast food, weighed the same 242lb after six months on Wegovy and also experienced constipation and sensitive skin.
- Researchers have identified factors that predict weaker response: older age, male sex, type 2 diabetes, and African American ancestry, with oestrogen and menstrual cycle phase also appearing to alter GLP-1 response.
- A 23andMe study found people carrying one copy of a genetic variant affecting GLP-1 brain receptors lose about 0.76kg extra on average, while two copies roughly doubles that — accounting for around 10% of expected weight loss.
- Endocrinologist Mahesh Umapathysivam and colleagues identified genetic variants affecting the PAM enzyme that appears to produce 'GLP-1 resistance,' meaning a given dose has less effect on appetite, insulin and gastric emptying.
- For non-responders, Prof Alexander Miras suggests switching to non-GLP-1 drugs like Mysimba or considering bariatric surgery, stressing that GLP-1 non-response does not predict surgical non-response.
Why it matters: With up to a third of patients getting minimal benefit from GLP-1 drugs that often cost over $1,000 a month privately, the lack of a predictive test leaves doctors and patients to discover failure after months of expense and side effects. The emerging genetic and demographic markers — including ancestry-based differences in response — point toward a future of tailored prescribing, but until those tests exist, many users will continue paying for medications that were never going to work for them.
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