By Deborah Borfitz 

May 13, 2026 | An engaged research cohort of over 11 million genotyped individuals has enabled 23andMe to produce a library of more than 300 peer-reviewed publications over the past 16 years. Following a 2025 bankruptcy filing, when it reemerged as a nonprofit medical research organization, the focus has settled on providing individuals with access to their genetic information, supporting genetics education, and studies that provide a deeper understanding of human genetics, says Adam Auton, vice president of human genetics at 23andMe Research Institute. 

A new major paper published under the new nonprofit structure is about GLP-1 drugs, determining that the efficacy and side effects people experience when taking the widely prescribed weight-loss medications have a genetic basis and may vary depending on the variety of medication they’re prescribed— semaglutide (sold under the brand names Ozempic and Wegovy), or tirzepatide (sold as Mounjaro or Zepbound). Results of the genome-wide association study, using data from 27,885 individuals who have used GLP-1 medications, were published recently in Nature (DOI: 10.1038/s41586-026-10330-z). 

In terms of weight loss, a key finding of the latest study is that a missense variant in the GLP1R gene is significantly associated with increased efficacy of GLP-1 drugs. Medication-related nausea and vomiting are also linked to variations in both the GLP1R and GIPR genes, but there are drug-specific effects—notably, that the association between the GIPR genetic variation and those adverse reactions is specific to individuals using tirzepatide but not semaglutide. 

The beauty of the study results is that they make “very clear biological sense,” notes Auton. “It all hangs together.”  

For members of the clinician-supervised Total Health service of 23andMe, available via a paid annual subscription ($499 initially, renewing for $199 annually), a new GLP-1 report and interactive tool offer- personalized guidance on the weight loss medications.  

Total Health, a physician-guided service introduced in 2023, includes exome sequencing, twice-a-year measurement of more than 55 blood biomarkers (via Quest Diagnostics), and access to physicians trained in genetics-informed preventive care and health action plans, according to a company spokesperson. Customers can contact these physicians directly via unlimited messaging and schedule an appointment for in-depth consultation tailored to their GLP-1 results or print out their reports to share with other physicians or specialists of their choosing. 

Genetic Predictors 

For individuals carrying two copies of one of the risk variants, genetics explain about 10% of the differences in therapeutic response to GLP-1 medications, reports Auton. That suggests that most of the variation in whether a drug works or fails is determined by non-genetic factors. As such, while the genetic contribution to efficacy may not be “make or break” for individuals preparing for their weight loss journey, he says, the side effects information can be quite meaningful. People carrying both the GLP1R and GIPR genetic variants have an approximately 14-fold increase in the rate of experiencing side effects. 

None of these learnings would have been possible without 23andMe’s many willing research volunteers and the company’s unique model for collecting this type of data, Auton stresses. Study participants readily agreed to complete a survey about their experiences with GLP-1 medications, including which one they were taking and for how long, the dosage, and the resulting weight loss and side effects. “This is very much a crowdsourced approach ... that is part of the 23andMe experience.”  

The recontactable genetics research community of the 23andMe Research Institute is the world's largest, with more than 80% of its over 14 million genotyped members having consented to participate in research. Researchers can gather data across a broader spectrum of behaviors and at a scale that would otherwise be difficult to do in a more traditional clinical setting, says Auton. 

Many of the studies conducted by 23andMe have been the largest of their kind, offering new genetic insights on conditions such as depression, Parkinson's Disease, COVID-19, lung cancer, and rare diseases. It is also responsible for breakthroughs in understanding human traits such as height, genetic ancestry, and sexual orientation. 

Modeling Outcomes 

Unlike standard reports, the GLP-1 pharmacogenetic report is delivered through an interactive tool designed for use in the physician-supervised Total Health service, says Auton. The tool allows members to model potential outcomes by combining genetic variants identified in the Nature study with demographics (age, sex, and starting body mass index) and health history (e.g., type 2 diabetes, non-alcoholic fatty liver disease, and high blood pressure). 

Information on expected weight loss and side effects in the GLP-1 report is presented in an easy-to-interpret format, based on the experience of research participants with the same genetic result. The meaning of an individual’s genetic variants is briefly described, along with an invitation to use the interactive tool for a better estimation of their likely experience on one of the prescribed drugs. 

Among this group of 23andMe research participants, weight loss estimates vary between 6% and 20% of starting weight, the company reports. The chances of nausea or vomiting range from 5% to 78%, depending on genetics and other factors.   

This knowledge could help inform GLP-1 medication choice and the dose escalation rate, says Auton. Total Health clinicians use these results alongside a member's blood labs and medical history to facilitate the shift from trial-and-error weight management toward data-driven decisions. “People can be on these medications for many months and spend thousands of dollars on them, so I think ... [it’s helpful] to understand the journey they may be on before making those decisions.” 

Research Opportunities 

While the GLP-1 study was a demonstration of the crowdsource research model used by 23andMe, Auton says that the 23andMe Research Institute is now focused on enabling more of the scientific community to access and analyze the data that it produces to expand the number of studies being conducted. Academic, not-for-profit, and commercial partners are all being sought in this quest. “We’re going to have to partner with all of those to maximize the benefit we can have ... while maintaining our ability to do that in a sustainable way.” 

Results of the Nature study could help inform the development of next-generation GLP-1 drugs. There are some “interesting questions still open,” points out Auton, including what’s driving the variation in weight regained by patients when they stop taking GLP-1 drugs. The medication class also appears to have benefits in disease areas beyond managing blood sugar and obesity.