Many individuals beginning GLP-1 treatments for weight loss often find them to be transformative: cravings diminish, exercise feels more manageable, and those stubborn pounds finally start to disappear. It’s almost like a dream come true.
However, a smaller group of patients doesn’t experience the same success. Clinical trials indicate that around 10 to 15% of those using GLP-1 medications like Wegovy and Zepbound are “non-responders” regarding significant weight loss. Recently published research suggested that genetics might be a contributing factor.
Yet, there’s ongoing research that highlights the benefits of GLP-1 drugs beyond just weight loss. For instance, clinical studies have pointed out that these medications can potentially lower the risks of heart attacks and strokes, and enhance outcomes for patients with heart failure—even in individuals who don’t shed pounds, or in some cases, may even gain weight.
Recent findings also reveal how these drugs might positively impact liver health. Wegovy, which uses the active ingredient semaglutide, received FDA approval in August for a serious liver condition known as metabolic dysfunction-associated steatohepatitis (MASH) that affects roughly 6% of adults in the U.S. A clinical trial demonstrated significant improvement in disease markers.
Dr. Daniel Drucker, a leading figure in GLP-1 research at the University of Toronto, remarked that while most believe the positive effects stem from weight loss, hints from his lab suggest that weight loss isn’t the only factor at play.
He believes the growing evidence should prompt health insurers and government programs to reconsider how they evaluate the effectiveness of these medications—shifting the focus from weight loss alone to the broader benefits they may provide across various serious health conditions.
Dr. Jody Dushay, who prescribes these medications at Beth Israel Deaconess Medical Center in Boston, pointed out that insurance companies typically require at least a 5% weight loss within three to four months to continue coverage for GLP-1 treatments. Given the recent insights about metabolic advantages independent of weight loss, it seems necessary to reevaluate this criterion.
She notes that around 5 to 8% of her patients could be categorized as “weight non-responders” to GLP-1s. These drugs are named after the hormone they mimic, which influences insulin secretion, stomach emptying, and appetite.
As Dushay mentioned, the increasing indications for these therapies suggest we really need to look for benefits even in those who don’t fit traditional weight loss responder profiles.
Dr. Drucker’s study, spearheaded by postdoctoral fellow Dr. Maria Gonzalez-Rellan, aimed to delve into why semaglutide seemed to enhance MASH markers irrespective of weight changes observed in clinical trials.
The research team pursued this by creating lab mice that mimicked “weight non-responders,” specifically removing GLP-1 receptors in the brain so they wouldn’t lose weight despite being treated with GLP-1 medications. Drucker explained that this approach allowed them to assess whether liver health improvements persisted without weight loss.
What they found was notable: even without weight reduction, significant benefits were still evident.
They discovered a unique group of liver cells that, when activated by GLP-1, communicate with the immune system to reduce inflammation. Drucker referred to these as a rare population of blood vessel cells playing a key role in minimizing inflammation.
To reinforce their findings, the team examined how mice lacking GLP-1 receptors in those liver cells fared after substantial weight loss—and notably, there was no liver improvement.
Dr. Harlan Krumholz, a cardiologist from Yale School of Medicine who wasn’t part of the study, commended the research as impressive. But he also cautioned that since it was conducted in mice, it’s uncertain if the same processes apply to humans.
However, Krumholz suggested that it provides a biologically plausible explanation for why some benefits of GLP-1 treatments seem to extend beyond mere weight loss.
The ability of GLP-1 medications to decrease inflammation could be an essential factor in their effectiveness for heart issues and conditions like kidney disease, independent of weight changes. A 2024 study of a significant cardiovascular trial involving Wegovy found its effectiveness in reducing the risk of subsequent heart attacks or strokes wasn’t contingent on the amount of weight lost.
Professor John Deanfield from University College London noted that potential positive impacts on blood sugar and blood pressure, alongside direct effects on heart health, may explain these outcomes.
That being said, Dr. Drucker emphasized that weight loss likely contributes significantly to improvements in conditions such as arthritis and sleep apnea, but this new research adds to the evidence that these medicines can be leveraged in more nuanced ways. Given their substantial costs and possible side effects, which often include nausea, a tailored approach might be necessary.
It’s crucial to consider whether the aim should be maximizing weight reduction—which sometimes requires higher dosages, thus potentially increasing side effects—or, as in the case of metabolic liver disease, utilizing a smaller dose to minimize adverse reactions and costs for patients.
Ultimately, Drucker pointed out the clinical importance of understanding how these medications function across various conditions.
