New light shed on who benefits most from weight-loss jabs

New light shed on who benefits most from weight-loss jabs

A recent study, published in Nature, reveals that individuals with specific genetic markers tied to hunger and digestion may achieve greater weight reduction when using drugs like Wegovy and Mounjaro. These medications mimic a natural gut hormone, reducing hunger and slowing digestion to promote satiety. The research suggests that genetic differences could explain why some users experience significant weight loss while others see minimal results or severe side effects, such as nausea and vomiting.

Over 1.6 million people in the UK have tried weight-loss medications in the past year, with most purchasing them privately through online pharmacies. The NHS provides Wegovy and Mounjaro to a smaller group, typically those with obesity and related health conditions. The study analyzed data from 15,000 participants who had previously enrolled in gene-testing via 23andMe, uncovering a genetic pattern linked to drug effectiveness and adverse reactions.

“The study found a genetic variant associated with weight loss, which was also linked to nausea,” said Professor Ruth Loos from the University of Copenhagen. “People lose more weight if they have this variant.” Those carrying two copies of the gene could see an average additional weight loss of 0.76kg (1.6lbs), doubling the typical effect.

The variant is more prevalent in individuals of European descent, with 64% having one copy and 16% possessing two. In contrast, only 7% of African Americans carry a copy. The research also identified another genetic marker connected to severe side effects, such as vomiting, in those using tirzepatide (Mounjaro). This could mean up to 1% of patients experience vomiting 15 times worse than average.

Experts emphasize that genetics is just one factor among many. Dr. Marie Spreckley from the University of Cambridge noted that “genetics is only one part of a much more complex picture,” highlighting the influence of behavioral, clinical, and treatment-related variables. These include exercise habits, dietary choices, and underlying health conditions. Additionally, factors like age, gender, and ethnicity appear to affect outcomes, though the reasons remain unclear.

Women, for instance, are more than twice as likely as men to lose 15% of their body weight on Mounjaro. Younger individuals, as well as those of white or Asian backgrounds, also show higher rates of weight reduction. However, the study’s findings require further validation, as other research has not confirmed the same links. “Overall, these findings are scientifically interesting, but they are a long way from changing clinical practice,” said Professor Naveed Sattar, a metabolic health expert. “What we really need now is more robust trial data to better define the balance of benefits and harms with these and many other emerging therapies.”

The potential for personalized treatment, or “precision medicine,” relies on integrating genetic and other patient data. While this could one day guide drug selection, the current evidence remains preliminary. The study’s results, though promising, underscore the need for more comprehensive analysis to ensure their reliability and applicability in real-world settings.