Ozempic contains one active ingredient: semaglutide, a lab-made version of a hormone your body naturally produces after eating. Each milliliter of the injectable solution holds 1.34 mg of semaglutide along with a small number of inactive ingredients that keep the drug stable and safe to inject.
The Active Ingredient: Semaglutide
Semaglutide belongs to a class of drugs called GLP-1 receptor agonists. GLP-1 (glucagon-like peptide-1) is a hormone your gut releases when food hits your digestive tract. It signals your pancreas to produce insulin, tells your liver to stop dumping sugar into your bloodstream, and communicates with your brain that you’ve eaten enough. The natural version of this hormone breaks down in minutes. Semaglutide is engineered to last much longer, with a half-life of roughly 6.5 days, which is why Ozempic only needs to be injected once a week.
The drug works on multiple systems at once. It boosts insulin release, but only when blood sugar is actually elevated, which lowers the risk of dangerous blood sugar crashes. It suppresses glucagon, a hormone that raises blood sugar. It slows how quickly your stomach empties food into your intestines, keeping you feeling full longer. And it acts on appetite centers in the brain, specifically the hypothalamus, to reduce hunger and food cravings.
The Inactive Ingredients
Beyond semaglutide itself, each milliliter of Ozempic solution contains:
- Disodium phosphate dihydrate (1.42 mg): a buffering agent that helps keep the solution at a stable pH of about 7.4, close to the pH of your blood
- Propylene glycol (14.0 mg): a common stabilizer used across injectable medications and food products
- Phenol (5.50 mg): a preservative that prevents bacterial growth in the multi-dose pen
- Water for injection: the base of the solution
Small amounts of hydrochloric acid or sodium hydroxide may also be added during manufacturing to fine-tune the pH. The final product is a clear, colorless liquid.
Available Doses and Pen Strengths
Ozempic comes in three prefilled pen configurations. The starter pen delivers doses of 0.25 mg or 0.5 mg per injection, with a total of 2 mg in 3 mL of solution. A mid-range pen delivers 1 mg per injection (4 mg in 3 mL). The highest-dose pen delivers 2 mg per injection (8 mg in 3 mL). Most people start at the 0.25 mg dose for the first four weeks, then step up gradually. Each pen contains multiple doses.
Before first use, pens need refrigeration between 36°F and 46°F. Once you’ve used a pen for the first time, it stays good for 56 days either in the fridge or at room temperature (up to 86°F). After 56 days, the pen should be discarded even if solution remains inside.
What Ozempic Is Approved to Treat
The FDA has approved Ozempic for three specific uses, all in adults with type 2 diabetes: improving blood sugar control alongside diet and exercise, reducing the risk of major cardiovascular events like heart attack and stroke in people who also have established heart disease, and reducing the risk of kidney disease progression in people who also have chronic kidney disease. Ozempic is not FDA-approved for weight loss on its own, though a higher-dose version of semaglutide (sold under the brand name Wegovy) does carry that approval.
How Your Body Processes It
After injection, semaglutide reaches steady levels in the bloodstream over the course of a few days. Your body breaks it down the same way it handles other proteins: enzymes snip apart the peptide backbone and process the fatty acid chain attached to it. About 53% of the drug’s breakdown products leave through urine, roughly 19% through stool, and only about 3% exits as intact semaglutide. A small amount (about 3%) is exhaled. Because the drug clears slowly, it takes about five weeks after your last injection for semaglutide to fully leave your system.
Key Safety Warnings
Ozempic carries an FDA boxed warning, the most serious type, regarding thyroid tumors. In rodent studies, semaglutide caused thyroid C-cell tumors at doses comparable to human use. Whether this translates to humans remains unknown, but the drug is not for anyone with a personal or family history of medullary thyroid carcinoma or a rare condition called Multiple Endocrine Neoplasia syndrome type 2. A lump in the neck, trouble swallowing, or persistent hoarseness are symptoms worth reporting immediately.
Pancreatitis is another concern, though the actual risk appears low. In clinical trials, confirmed cases of acute pancreatitis occurred in about 0.3% of Ozempic-treated patients per year, a rate similar to what was seen in people taking a placebo. Persistent, severe abdominal pain (sometimes radiating to the back) is the hallmark symptom. People with a history of pancreatitis are generally directed toward other medications.