One in eight adults in the US have taken the weight loss drugs like Ozempic, according to survey analysis. But more than 30 percent of those drop the meds after just four weeks, according to a study by Blue Health Intelligence, a US healthcare data company, before the drug can have a meaningful impact on their health.Along with weight loss, Ozempic, which is also sold under the brand name Wegovy, has also won a reputation for its unpleasant side effects. The most common side effects people report are nausea, diarrhea or other digestive problems.Vision changes, erectile dysfunction and mood changes have also been reported, and you may have heard of side effect phenomena like ʺOzempic faceʺ or ʺOzempic buttʺ (sagging in all the wrong places).But what’s worrying medical professionals more are reports of severe medical illnesses after taking the weight loss drug, also called semaglutide or GLP-1 drugs, for several months.ʺThe most concerning side effects include pancreatitis and the effects on musculoskeletal disorders,ʺ Penny Ward, a physician-doctor at Kings College London, UK, told DW.A UK regulator has highlighted potentially deadly side effects of acute pancreatitis — an inflammation of the pancreas — after at least ten deaths were linked to this condition among British users of GLP-1 drugs.
Side effects after clinical trials ‘not unusual’
GLP-1 drugs have been on the US market since 2017. Ozempic was first approved to treat type 2 diabetes, while Wegovy was approved as a weight-loss medication in 2021.Clinical trials testing their safety and effectiveness showed them to be safe enough for their intended users. But since being release to the public, people have been reporting new side effects that hadn’t appeared in the original clinical trials.Ward said it’s ʺnot unusualʺ for additional adverse reactions to be noted once a product goes into clinical use. ʺRarer side effects may emerge as more patients take these medicines in clinical practice,ʺ she said, “simply as a result of the much larger number of people treated than were included in the clinical development trials.ʺThis is why we continue to monitor the safety of medicines on the market,ʺ Ward added.A major study published in the journal Nature Medicine in January 2025 set out to systematically analyse all the reported health risks of over 215,000 people taking GLP-1 drugs to treat diabetes.The researchers found risks of taking GLP-1 drugs beyond those previously recognized in clinical trials, including an 11 percent increased risk in arthritis and a 146 percent increased risk of pancreatitis. Increased risks of low blood pressure, dizziness or fainting, kidney stones and kidney inflammation were also reported.The study also highlighted well-known risks of several gastrointestinal disorders, backing up numerous past studies showing an increased risk of gastrointestinal side effects.
More research on side effects needed
Last year, people also started reporting that they’d gone blind after taking Wegovy. Researchers who investigated the matter found that GLP-1 drugs are associated with an increased risk of a disease affecting the optic nerve, called nonarteritic anterior ischemic optic neuropathy (NAION).While the condition is rare, affecting an estimated 10 in 100,000 people, a study published in the journal JAMA Ophthalmology found that people with diabetes taking GLP-1 drugs are four times more likely to develop NAION than the population average.ʺThis research does suggest an association between semaglutide treatment and one form of sight-threatening optic neuropathy, but this would ideally be tested in larger studies,ʺ Graham McGeown, an honorary professor of physiology at Queen’s University Belfast, UK.Experts say much more research is needed in representative populations to better understand the side effects of GLP-1 drug and their real-world risks for people taking them.ʺFor example, [more data is needed about] those taking the drug for obesity, who need a higher dose compared to people with diabetes, and taking it for longer than two years,ʺ said Karolina Skibicka, a neuroendocrinologist at University of Calgary, Canada.ʺBut especially, we need studies which include women. Women show unique side-effects to many pharmacotherapies, and still [in] most studies women are often underrepresented at various stages of testing,ʺ Skibicka added.
Benefits outweigh the risks
Despite concerns about new side effects, Skibicka told DW, ʺthe list of benefits for this drug, if taken as prescribed, is still significantly longer and more impactful than risks. It has the promise of saving and improving many lives.ʺAs such, Skibicka said it was ʺunlikelyʺ that the appearance of rare but serious side effects would be grounds to create new, stricter recommendations for prescribing GLP-drugs.Researchers are also finding surprising ‘beneficial’ side effects of taking GLP-1 dugs, too.Studies show that GLP-1 drug use is associated with a reduced risk of dementia and Alzheimer’s disease. Researchers are also investigating whether the drugs could be used to treat substance use disorders.The January study also reported reduced risks of blood coagulation and clotting disorders, cardiorenal and metabolic disorders, and several respiratory conditions in diabetic patients taking GLP-1 drugs.The authors speculate that GLP-1 drugs might influence the risk of so many conditions for two reasons: first because they act on many parts of the body, and second because they treat obesity, which contributes to several health issues.