Background: Individual differences in response to GLP-1 treatment

Associations have been reported between weight loss response to glucagon-like peptide-1 (GLP-1) receptor agonists and genetic variants. In a prediction model incorporating both genetic and non-genetic factors, genetic factors had a much smaller influence than non-genetic factors. Caution is needed when interpreting genetic information as determining treatment outcomes.

A research highlight by Margot Brandt, published in Nature Genetics on May 14, 2026, covered a Nature study by Su et al. The researchers analyzed changes in body mass index (BMI) and side effects during treatment with GLP-1 receptor agonists using surveys completed directly by 23andMe participants. The study examined individual differences in drug response in relation to genetic information.

The supplied publicly available highlight text did not specify the number of participants, the breakdown by drug, doses, or treatment duration. It is therefore difficult to extrapolate the findings to specific drugs or dosing conditions.

Key findings: A genetic locus associated with weight loss and side effects

The signal most strongly associated with BMI reduction was a missense variant in GLP1R, the gene encoding the GLP-1 receptor. A missense variant is a genetic variant that changes an amino acid in a protein. The highlight reported that this variant was associated with a 0.76 kg difference in weight loss per allele. However, because the effect allele and direction were not specified, this cannot be interpreted definitively as either 0.76 kg of additional weight loss or 0.76 kg less weight loss.

The same locus was also associated with side effects, including nausea and vomiting. This offers a lead for studying individual differences in both treatment efficacy and tolerability. However, observing associations at the same locus does not establish that weight loss and side effects arise from the same variant or mechanism.

The precise effect of the variant on the receptor protein has not yet been determined. The highlight proposed that altered protein stability might affect the amount of receptor on the cell surface. This is a possible mechanistic hypothesis, not evidence demonstrating changes in drug-binding affinity or impaired intracellular signaling.

The researchers also built a model to predict BMI reduction using genetic and non-genetic predictors together. Genetic factors had a much smaller influence than non-genetic factors in this model. The supplied text did not report the specific contribution of each factor or the model's predictive performance.

Meaning and outlook: Validation remains before personalized prescribing

These findings add support for considering genetic differences when seeking to understand responses to GLP-1 receptor agonists. However, discovering an association with a genetic variant is distinct from validating a prediction tool for use in patients. The highlight only suggested that further research could contribute to predicting individual treatment responses and side effects.

The study's reliance on self-reported surveys should also be considered when interpreting the findings. Based on the supplied highlight alone, it is difficult to assess the accuracy of weight-change and side-effect measurements, the comparison conditions, or adjustments for confounding factors. The variant's specific function and the potential clinical use of the prediction model could not be confirmed from this material either.

A task for future research is to determine how much genetic information improves prediction of treatment response and side effects beyond non-genetic factors. The available findings do not provide sufficient evidence to recommend drug selection or alternative treatment based on genetic testing.

Source: Nature Genetics research highlight. The DOI of the original study cited by the highlight is 10.1038/s41586-026-10330-z; this article is based on the supplied publicly available text of the highlight.