New light shed on who benefits most from weight-loss jabs
New light shed on who benefits most from weight-loss jabs
Recent research published in the Nature journal highlights how genetic differences can influence the effectiveness of weight-loss medications. Scientists found that individuals with specific variations in two genes related to hunger and digestion may achieve greater weight reduction when using drugs such as Wegovy and Mounjaro. These findings could help clarify why some patients experience dramatic results while others see minimal progress, or suffer severe side effects like nausea and vomiting.
These medications work by mimicking a natural hormone produced in the gut, which suppresses appetite and promotes a feeling of fullness. While genetic factors may play a minor role in determining their success, experts emphasize that lifestyle choices, health conditions, and even demographic characteristics also affect outcomes. For instance, previous studies suggest women are more than twice as likely as men to lose significant weight on Mounjaro, and younger individuals, particularly those of white or Asian descent, may also benefit more, though the exact reasons remain unclear.
The study analyzed data from 15,000 people who had participated in genetic testing through 23andMe. By examining millions of DNA variations, researchers identified a pattern linking certain gene forms to both weight loss and adverse reactions. Professor Ruth Loos of the University of Copenhagen noted,
“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.”
Participants with two copies of the gene lost an average of 0.76kg (1.6lbs) extra compared to those with one copy. However, the variant is more common in people of European ancestry, with 64% carrying one copy and 16% having two, whereas only 7% of African Americans possess a single copy.
Another gene variation was connected to severe side effects, particularly vomiting, when taking tirzepatide (Mounjaro). This could mean up to 1% of users experience vomiting 15 times worse than typical. While the genetic impact is modest, Prof Loos called it “similar to other factors and not trivial.” Nevertheless, she added that the findings need confirmation through additional studies.
Dr Marie Spreckley from the University of Cambridge stressed that genetics is just one piece of the puzzle. She pointed out that behavioral choices, clinical conditions, and treatment specifics like dosage and duration are critical. For example, the type of medication, how long it’s used, and the patient’s adherence to healthy habits all contribute to weight loss outcomes. The National Health Service (NHS) provides Wegovy and Mounjaro to a limited group, while most people purchase these drugs privately through online pharmacies.
Despite the potential for personalized treatment, Professor Naveed Sattar from the University of Glasgow cautioned,
“These findings are scientifically interesting, but they are a long way from changing clinical practice.”
He argued that more comprehensive trial data is needed to better understand the risks and benefits of these therapies. In the future, combining genetic and clinical data could support precision medicine, helping doctors select the most effective drug for each patient.
