Ozempic has been used off-label for weight loss since roughly 2019, though it was originally approved by the FDA in 2017 as a diabetes medication. That means doctors have been prescribing it specifically to help patients lose weight for about five to six years, even though it has never been formally approved for that purpose. The drug approved for weight loss is Wegovy, which contains the same active ingredient at a higher dose.
Ozempic’s Original Approval and Early Off-Label Use
The FDA approved Ozempic in December 2017 for adults with type 2 diabetes. It was designed to help control blood sugar, but patients and their doctors quickly noticed a significant side effect: weight loss. By 2018, 92% of people filling Ozempic prescriptions had a diabetes diagnosis. By 2021, that number had dropped to 77%, according to the Health Care Cost Institute. That 15-point shift represents a rapid rise in off-label prescriptions, mostly for weight management.
The trend accelerated through 2022 and into 2023, fueled by social media attention and celebrity endorsements. Demand grew so sharply that it created widespread shortages, making it harder for diabetes patients to fill their prescriptions.
When Formal Weight Loss Research Began
Even before off-label use took off, Novo Nordisk (the company behind both Ozempic and Wegovy) was running clinical trials to test semaglutide specifically for obesity. The first major trial, known as STEP 1, enrolled its first participants in June 2018 and completed primary data collection by March 2020. These trials used a higher dose of semaglutide (2.4 mg per week) than what Ozempic provides (up to 2 mg per week), and the results were strong enough to support a separate FDA approval.
That approval came in June 2021, when the FDA cleared Wegovy for chronic weight management in adults with obesity or overweight with at least one weight-related health condition. The European Medicines Agency followed in January 2022.
Ozempic vs. Wegovy for Weight Loss
Both Ozempic and Wegovy contain semaglutide, but they’re dosed differently. Ozempic maxes out at 2 mg per week, while Wegovy goes up to 2.4 mg. That higher ceiling matters. Clinical trials of the 2.4 mg dose showed more consistent and larger weight reductions, which is why Wegovy is considered the better option when weight loss is the primary goal.
In practice, many people still receive Ozempic off-label for weight loss because of insurance coverage issues, Wegovy supply problems, or prescriber preference. The two drugs work the same way: they mimic a gut hormone that slows digestion, reduces appetite, and signals the brain to feel full sooner. The difference is really about dosing and what’s printed on the label.
What the Longest Studies Show
The largest and longest trial of semaglutide for weight loss, called SELECT, followed over 17,600 adults across 41 countries for an average of 40 months. Participants were 45 or older, had overweight or obesity, and did not have diabetes. Those taking semaglutide lost an average of 10% of their body weight and more than 7 centimeters from their waistline over four years.
Weight loss in the semaglutide group continued through about week 65, then held steady for the remaining years of the trial. That plateau is normal and reflects the body reaching a new equilibrium rather than the drug losing effectiveness. Notably, the semaglutide group experienced fewer serious side effects than the placebo group over the full four years, which provides reassurance about sustained use.
A separate 68-week trial tested what happens when people stop the drug. Patients who switched from semaglutide to placebo after 20 weeks regained weight, ending up with only about 5% total loss compared to roughly 8% in those who stayed on the medication. This pattern has made it clear that semaglutide works best as an ongoing treatment rather than a short course.
The Practical Timeline
Putting it all together: semaglutide has been studied for weight loss in clinical trials since mid-2018, prescribed off-label for weight loss in growing numbers since around 2019, and available as an FDA-approved weight loss drug (as Wegovy) since June 2021. The longest safety data now stretches to four years. While the cultural explosion around Ozempic feels recent, the science behind using this class of drug for weight management has been building for more than six years.