Genetics May Predict Your GLP-1 Drug Response, Landmark Study Shows

If you've ever wondered why your friend lost 30 pounds on Wegovy while you barely budged the scale, the answer might be written in your DNA. Specific changes in two genes appear to help predict whether you will lose substantial weight on GLP-1 drugs used to treat obesity — and whether the drugs will cause nausea or vomiting, according to groundbreaking research published yesterday in Nature.

The study, conducted by the 23andMe Research Institute, represents the largest genetic analysis of GLP-1 drug response to date. "I think we have proof of concept here that genetics is playing a role in terms of GLP-1 efficacy and side effects," said Adam Auton, a vice president at the 23andMe Research Institute and the senior author on the paper.

Why Some People Don't Respond to GLP-1s

Of all the millions of people who have tried weight-loss drugs such as Wegovy and Zepbound, nearly one in four people don't respond to treatment. They lose little weight, or none at all, and see few health improvements. This puzzling reality has left both doctors and people struggling with weight management searching for answers.

The researchers surveyed over 27,885 people who had reported using at least one of Ozempic, Wegovy, compounded semaglutide, Mounjaro, Zepbound or compounded tirzepatide. Study participants were mostly female (82.4%) with a median age of 52 years, with most respondents of European ancestry (78.3%), although the study also included substantial representation from Latino (12.9%) and African American (4.2%) ancestries.

The genetic analysis revealed remarkable variation in response. Substantial inter-person variability exists in both weight loss efficacy and the incidence of side effects, with some people losing more than 20% of their body weight while others shed less than 5%.

This variability helps explain why your healthcare provider might need to try different approaches or medications to find what works best for you. Understanding that genetics play a role can remove some of the frustration when your results differ from others' experiences.

The Genetic Variants That Matter

The study identified two key genetic variants that significantly influence GLP-1 drug response:

Weight Loss Effectiveness: Researchers identified a missense variant in GLP1R that is associated significantly with increased efficacy of GLP1 medications (P = 2.9 × 10−10), with an additional −0.76 kg of weight loss expected per copy of the effect allele. People with one copy of the higher-weight-loss variant, rs10305420, lost an average of about 1.7 pounds more than those without it, while those with two copies of the variant lost more than three pounds more than people without any copies.

Side Effect Risk: The researchers identified associations linking variation in both GLP1R and GIPR to GLP1 medication-related nausea or vomiting, with the GIPR association being restricted to people using tirzepatide. This finding makes biological sense since tirzepatide targets both GLP-1 and GIP receptors, unlike semaglutide which only targets GLP-1.

"The genetic variant we found lands right in this gene [for] the GLP-1 receptor, which happens to be the target for these medications," explained Auton. The result "makes perfect biological sense," he added.

Predicting Your Response Before You Start

The researchers incorporated their genetic findings into broader models that combine demographic, clinical and genetic features to predict efficacy and side effects, and demonstrated the ability of this model to stratify people by weight loss in a held out electronic health record (EHR) dataset.

23andMe has already translated these findings into actionable information. The organization has released a new report, called GLP-1 Medications Weight Loss and Nausea, to members of its Total Health service. The new report provides insight into weight loss and nausea risk when taking a GLP-1 medication based on these new findings.

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

This wide range suggests that personalized medicine approaches could help you and your healthcare provider make more informed decisions about which GLP-1 medication might work best for your unique genetic makeup.

Study Limitations and Expert Perspectives

Outside researchers were impressed and intrigued by the findings, but some doubted whether the genetic results would impact care. Co-author Adam Auton acknowledges that the association was modest. "There's a number of factors that can influence weight loss, of which genetics is a subcomponent." But he notes that the genetic association with side effects was more substantial.

The study relied on self-reported data, which can introduce variability. However, the large sample size makes the findings compelling, says Andrea Ganna, a health data scientist at the University of Helsinki.

The results highlight the opportunity for pharmacogenetics and precision medicine approaches applied to GLP1 medication, potentially ushering in an era where genetic testing helps determine not whether to prescribe a GLP-1 drug, but which one might work best for each individual.

What This Means for You

If you've been considering GLP-1 medication or haven't seen the results you hoped for, this research offers new hope for a more personalized approach. While genetic testing for GLP-1 response isn't yet standard clinical practice, these findings suggest we're moving toward a future where your DNA could help guide treatment decisions.

For now, the key is working with healthcare providers who understand that GLP-1 response varies significantly between individuals. If you haven't had success with one medication, switching to another might be worth discussing, as different drugs may interact differently with your genetic makeup.

Don't let previous disappointing results discourage you from exploring your options. The wide genetic variation in response means that finding the right medication for your body may require some patience and experimentation with your healthcare team.

If you're ready to explore GLP-1 treatment options with providers who stay current on the latest research, find a clinic near you that can help create a personalized treatment plan based on your individual needs and circumstances.

Sources

1. Genetic predictors of GLP1 receptor agonist weight loss and side effects - Nature study by 23andMe Research Institute
2. 23andMe finds genetic changes appear to help predict response to GLP-1 drugs for weight loss - STAT News coverage
3. How well GLP-1 weight loss drugs work may depend on your genetics - Scientific American analysis