New light shed on who benefits most from weight-loss jabs
New Insights on Weight-Loss Drug Efficacy and Individual Responses
A recent study published in the Nature journal indicates that individuals with specific genetic variations may experience greater weight reduction when using medications like Wegovy and Mounjaro. These drugs function by mimicking natural gut hormones that suppress appetite, making users feel satiated. The research highlights how genetic differences can influence both the effectiveness of these treatments and the occurrence of side effects.
Genetic Variants Linked to Weight Loss and Nausea
Scientists examined data from 15,000 participants who had undergone gene testing via 23andMe. Their findings revealed a connection between particular genetic markers and the extent of weight loss achieved. One variant was associated with increased weight reduction, while another correlated with severe nausea and vomiting. People carrying two copies of the first variant, which is more common in individuals of European descent, could see nearly double the weight loss compared to those with one copy.
“The study found a genetic variant associated with weight loss, which was also linked to nausea. People who have this variant tend to lose more weight,” explained Professor Ruth Loos from the University of Copenhagen.
According to the research, 64% of Europeans carry one copy of the variant, with 16% having two. This contrasts with 7% of African Americans with one copy. The presence of the variant appears to contribute to the variability in weight loss outcomes, though experts caution that it is not the sole determinant.
Factors Beyond Genetics Shape Results
Dr. Marie Spreckley of the University of Cambridge emphasized that genetics is just one aspect of a broader, complex equation. Behavioral choices, clinical conditions, and treatment specifics—such as exercise routines, dietary habits, and support systems—also play significant roles. For instance, previous studies suggest women are more than twice as likely as men to achieve a 15% body weight reduction with Mounjaro. Demographic factors like age, ethnicity, and other health issues may further influence effectiveness, though the exact mechanisms remain unclear.
Weight loss percentages can differ significantly among individuals using these medications. Trials showed semaglutide (Ozempic, Wegovy) led to about 14% weight loss, while tirzepatide (Mounjaro) achieved up to 20%. In the study, participants averaged 11.7% loss over eight months, with some reporting 30% reduction and others little to none.
While the genetic impact is modest, Professor Naveed Sattar from the University of Glasgow noted it “is similar to other factors—and not trivial.” However, he added that the findings require validation in additional studies. “Overall, these results are scientifically intriguing, but they are a long way from altering clinical practice,” he stated.
The potential for personalized treatment options—known as “precision medicine”—could arise from combining genetic and other data. This approach might help tailor drug choices to maximize benefits and minimize risks. Yet, for now, such applications remain in development. Most weight-loss drug users in the UK are purchasing them privately through online pharmacies, with the NHS reserving Wegovy and Mounjaro for a select group with obesity and related health concerns.
