Why Do Weight Loss Jabs Work Differently? Your DNA Might Hold a Clue

Daily Health

09/04/2026

Weight-loss medications known as GLP-1 agonists, such as semaglutide (Wegovy) and tirzepatide (Mounjaro), have become a significant tool in managing obesity. They work by mimicking natural gut hormones that regulate appetite and digestion. However, a common question has emerged: why do some individuals experience dramatic weight loss while others see more modest results? New research suggests our genetics may play a role.

The Genetic Link to Treatment Response

A recent study published in the journal Nature explored the genetic data of nearly 28,000 people using GLP-1 medications. Researchers investigated how variations in our DNA might influence the effectiveness and side effects of these popular drugs. The core idea is that since these drugs interact with specific biological pathways, genetic differences in those pathways could lead to different outcomes for patients.

Key Findings on Weight Loss and Side Effects

The research identified specific genetic variants that appear to be associated with how people respond to these treatments. For instance, individuals carrying a particular variant in the GLP-1 receptor gene (rs10305420) were found to lose slightly more weight compared to those without it. Another variant (rs1800437) was linked to a higher likelihood of experiencing side effects like nausea and vomiting, particularly with the drug tirzepatide. These findings provide a plausible biological explanation for some of the variability seen in clinical practice.

A Piece of a Much Larger Puzzle

While these genetic links are a fascinating discovery, it is crucial to place them in context. The study's authors and other experts in the field emphasize that the overall impact of these genetic variants is modest. The research suggests that non-genetic factors—such as the specific drug used, dosage, duration of treatment, and a person's sex—account for a much larger portion of the difference in weight-loss results. Genetics is just one piece of a highly complex picture.

What This Means for Treatment Today

This research marks an important step toward a future of precision medicine, where treatments could be tailored to an individual's genetic profile. However, the evidence is not yet strong enough to support using genetic testing to guide treatment decisions in routine clinical practice. For now, discussions about starting, stopping, or changing obesity medications should be had with a healthcare provider. They can help navigate the benefits and risks based on a comprehensive view of your health, where genetics is just one of many contributing factors.

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