Ozempic is a weekly injectable medication approved by the FDA to treat type 2 diabetes in adults. It contains semaglutide, a compound that mimics a natural gut hormone to help control blood sugar, and it has gained widespread attention for its significant weight loss effects. Beyond blood sugar management, Ozempic now carries two additional FDA-approved uses: reducing the risk of heart attacks, strokes, and cardiovascular death in adults with type 2 diabetes and heart disease, and slowing kidney disease progression in adults with type 2 diabetes and chronic kidney disease.
How Ozempic Works in the Body
Your gut naturally produces a hormone called GLP-1 after you eat. It signals your pancreas to release insulin, slows digestion, and tells your brain you’re full. The problem is that natural GLP-1 breaks down within minutes. Semaglutide, the active ingredient in Ozempic, is a synthetic version that shares 94% of its structure with human GLP-1 but lasts long enough to work with a single weekly injection.
Once injected, semaglutide does several things at once. It triggers insulin release, but only when blood sugar is elevated, which lowers the risk of dangerous blood sugar drops. It suppresses glucagon, a hormone that tells your liver to dump sugar into the bloodstream. It slows the rate at which food leaves your stomach, so glucose enters your blood more gradually after meals. And it acts on appetite centers in the brain, reducing hunger and food cravings. This combination of effects is why Ozempic lowers blood sugar and causes weight loss simultaneously.
Blood Sugar Control in Type 2 Diabetes
Ozempic’s primary approved use is improving blood sugar control in adults with type 2 diabetes, alongside diet and exercise. In the SUSTAIN clinical trial program, the 1 mg dose reduced A1C (a measure of average blood sugar over roughly three months) by 0.38 to 1.07 percentage points more than comparison treatments. For context, most diabetes guidelines consider an A1C drop of 0.5 percentage points clinically meaningful, so these reductions represent a substantial improvement for many patients.
The medication is injected once a week, which is a notable convenience compared to daily diabetes medications. You start at a low dose of 0.25 mg for the first four weeks, which is not actually a treatment dose. It exists solely to let your body adjust and minimize side effects. From there, the dose increases gradually, with a maximum recommended dose of 2 mg once weekly.
Heart and Kidney Protection
In January 2025, the FDA expanded Ozempic’s label to include two additional uses, both for people who already have type 2 diabetes plus other serious conditions.
For adults with type 2 diabetes and established heart disease, Ozempic is approved to reduce the risk of cardiovascular death, non-fatal heart attack, and non-fatal stroke. This makes it one of the few diabetes drugs that has proven cardiovascular benefits beyond simply lowering blood sugar.
For adults with type 2 diabetes and chronic kidney disease, the evidence is equally striking. The FLOW trial found that semaglutide reduced the risk of major kidney events (including kidney failure, significant loss of kidney function, and death from kidney or cardiovascular causes) by 24% compared to placebo. Kidney function also declined more slowly: patients on semaglutide lost about 1.16 fewer units of kidney filtration capacity per year. Cardiovascular death specifically was 29% lower in the semaglutide group. The trial was actually stopped early because the benefits were so clear.
Weight Loss Effects
Ozempic is not FDA-approved for weight loss on its own. That approval belongs to Wegovy, which contains the same drug at a higher maximum dose. However, significant weight loss is a well-documented effect of Ozempic, and many doctors prescribe it off-label for this purpose.
The weight loss data comes primarily from the STEP trial program, which tested semaglutide at the higher 2.4 mg Wegovy dose. In one two-year trial, participants lost an average of 15.2% of their body weight, compared to 2.6% in the placebo group. That translates to roughly a 12.6 percentage point difference. For someone weighing 220 pounds, that would mean losing about 28 pounds more than they would have with diet and exercise alone. Earlier trials showed placebo-subtracted weight losses of 10 to 12% over about 16 months.
At the lower doses used in Ozempic (up to 2 mg versus Wegovy’s 2.4 mg), weight loss is still significant but somewhat less dramatic. Many patients prescribed Ozempic for diabetes experience meaningful reductions in body weight as a secondary benefit.
Ozempic vs. Wegovy
Since both contain semaglutide, the most common question is what actually differs between them. The distinctions are regulatory, not chemical.
- Approved uses: Ozempic is approved for type 2 diabetes, cardiovascular risk reduction (in people with diabetes and heart disease), and kidney protection (in people with diabetes and kidney disease). Wegovy is approved for weight management in adults and children 12 and older, for a type of liver disease called MASH, and for cardiovascular risk reduction in adults with obesity or overweight and heart disease.
- Maximum dose: Ozempic tops out at 2 mg weekly. Wegovy goes up to 2.4 mg.
- Injection device: Ozempic uses a multi-use pen (you dial your dose and use the same pen for multiple injections). Wegovy comes as a single-use, pre-filled pen.
Both are injected once a week, and both are also available in a daily oral pill form.
Common Side Effects
Digestive side effects are the most frequent complaint and the main reason people stop taking GLP-1 medications. In the SUSTAIN trials (testing the diabetes doses), nausea occurred in 15 to 24% of patients, vomiting in 7 to 15%, diarrhea in 7 to 19%, and constipation in 4 to 7%. At the higher doses used for weight loss in the STEP trials, these numbers climb considerably: nausea hit 14 to 58% of participants, and constipation affected 12 to 37%.
These side effects are most common during dose increases and typically improve over weeks as the body adjusts. This is exactly why the dosing schedule starts low and ramps up gradually. Most people who tolerate the first few months of treatment find that nausea and other gut symptoms settle down significantly.
Who Should Not Take Ozempic
Ozempic carries a boxed warning, the FDA’s most serious label alert, regarding thyroid tumors. In animal studies, semaglutide caused thyroid tumors including a type called medullary thyroid carcinoma. It is not known whether this risk applies to humans, but as a precaution, Ozempic is contraindicated for anyone with a personal or family history of medullary thyroid carcinoma or a condition called Multiple Endocrine Neoplasia syndrome type 2. Signs to be aware of include a lump in the neck, difficulty swallowing, shortness of breath, or persistent hoarseness.
People who have had a serious allergic reaction to semaglutide or any inactive ingredient in Ozempic should also avoid it. Ozempic is not approved for type 1 diabetes and has not been studied in people with a history of pancreatitis, though it is not formally contraindicated in that group.