Despite the widespread use of GLP-1 weight-loss medications, a proportion of patients experience minimal benefit, with some losing less than 5% of their body weight in clinical trials. This non-response rate varies between 9% and a third of participants, depending on the specific drug and dosage.
Researchers are currently working to understand the reasons behind these varied responses. This research aims to help doctors tailor drug use, improve cost-effectiveness, and reduce side-effects.
Factors that may influence a patient's response to GLP-1 medications include age, with older individuals potentially losing less weight, and sex, as men may lose less weight than women. People with type 2 diabetes also tend to lose less weight compared to those without the condition. Studies have also suggested that ancestry could play a role, with the drugs potentially being most effective in people of European ancestry and least effective in those of African American ancestry.
Hormonal factors, such as oestrogen levels, are also being investigated for their potential impact on GLP-1 response. The use of menopausal hormone replacement therapy, which contains oestrogen, has been associated with greater weight loss in users of semaglutide.