Genetics may shape GLP‑1 response
A study using self‑reported data from nearly 28,000 people suggests genetic differences may explain why some users of semaglutide or tirzepatide lose less weight than others, according to recent reporting (independent.co.uk). The reporting notes that variable outcomes are showing up in large, real‑world datasets as use expands (independent.co.uk).
Weight-loss drugs mimic gut hormones that slow digestion and curb appetite, but a new Nature study found DNA may help explain why results differ from person to person. (nature.com) Researchers analyzed genetic data and self-reported treatment outcomes from 27,885 people who said they had used glucagon-like peptide 1 receptor agonists, including semaglutide and tirzepatide. The paper was published April 8, 2026. (nature.com) The team found a protein-altering variant in the GLP1R gene, which encodes the receptor these drugs target, that was linked to greater weight loss. Each copy of the variant was associated with an additional 0.76 kilograms, or about 1.7 pounds, of weight loss. (nature.com) The study also linked variation in GLP1R and in GIPR, a related gut-hormone receptor gene, to nausea and vomiting. The GIPR signal appeared only in people taking tirzepatide, which acts on both the glucagon-like peptide 1 and gastric inhibitory polypeptide pathways. (nature.com) That split matches how the medicines work. Semaglutide targets the glucagon-like peptide 1 receptor alone, while tirzepatide targets both glucagon-like peptide 1 and gastric inhibitory polypeptide receptors. (nature.com) The researchers said responses to these drugs already vary widely in practice. In the 23andMe summary of the findings, some users lost less than 5% of body weight while others lost more than 20%. (23andme.com) Outside experts said the genetic effect on weight loss was real but small. Marie Spreckley of the University of Cambridge told The Independent that sex, drug type, dose, and treatment duration appear to explain much more of the variation than the newly identified variants do. (independent.co.uk) The paper points toward pharmacogenomics, the use of DNA to predict how a patient will respond to a drug, but it does not give doctors a ready-made test. Nature’s news coverage said the study offers clues for precision medicine, while the authors described the current model as a foundation rather than a clinical tool. (nature.com 1) (nature.com 2) The study has limits that matter. It relied on self-reported medication use, weight loss, and side effects from 23andMe participants, not on randomized trial data or medical records alone. (nature.com) 23andMe also moved quickly to commercialize the work. On the same day the paper appeared, the company said it had added a “GLP-1 Medications Weight Loss and Nausea” report to its Total Health service. (23andme.com) For now, the clearest takeaway is narrower than the hype: the same drugs can produce very different outcomes, and this study suggests part of that gap is written into the genes that those drugs are designed to hit. (nature.com)
