What Is Ozempic? A Plain-Language Explainer

Ozempic is a brand name, not a drug

The drug is semaglutide. It is a GLP-1 receptor agonist with 94% sequence homology to human GLP-1 that binds and activates the GLP-1 receptor, including receptors in brain areas that regulate appetite and calorie intake, and it delays gastric emptying [3]. The injection goes under the skin of the abdomen, thigh or upper arm once a week, at any time of day, with or without meals [3].

Novo Nordisk's Ozempic injection was approved on December 5, 2017, under application 209637 [1]. The injection comes in pens delivering weekly doses from 0.25 mg up to 2 mg [1][3]. An oral Ozempic tablet also exists, in 1.5 mg, 4 mg and 9 mg strengths, and it was approved under the Rybelsus application rather than the injection's [2][4].

After an injection, semaglutide peaks in the blood at 1 to 3 days and has an elimination half-life of about a week. It is broken down by cleavage of the peptide backbone rather than by CYP enzymes, and about 3% of a dose is excreted unchanged in urine [3]. That long washout is why the label tells women to stop Ozempic at least 2 months before a planned pregnancy [3].

What Ozempic is approved to treat

The Ozempic injection label, effective June 1, 2026, lists three indications [3]:

• As an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes.
• To reduce the risk of major adverse cardiovascular events — cardiovascular death, non-fatal heart attack or non-fatal stroke — in adults with type 2 diabetes and established cardiovascular disease.
• To reduce the risk of sustained eGFR decline, end-stage kidney disease and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.

Safety and efficacy have not been established in pediatric patients [3].

Neither the Ozempic injection nor the tablets has a weight-loss indication [3][4]. Semaglutide 2.4 mg has instead been studied for weight management, and FDA lists Wegovy as a separate semaglutide product [5][6].

Ozempic, Wegovy and Rybelsus: different labels

All three contain semaglutide, but they are separate FDA-approved products with different indications, different dose ranges and different prescribing information. Wegovy injection was approved on June 4, 2021 [6]. Its weight-management trials tested 2.4 mg weekly, and a 7.2 mg strength now exists for adults [6][7].

Rybelsus and Ozempic tablets are not substitutable on a milligram-for-milligram basis, even though both are oral semaglutide [4]. Tablet dosing follows its own schedule — Rybelsus starts at 3 mg for 30 days and Ozempic tablets at 1.5 mg for 30 days, and those starting doses are not effective for glycemic control [4].

How Ozempic is dosed

The injection starts at 0.25 mg once weekly for 4 weeks, a dose the label describes as a starting dose rather than a maintenance dose, then moves to 0.5 mg [3]. If more glycemic control is needed, the dose rises to 1 mg after at least 4 weeks on 0.5 mg, then to 2 mg after at least 4 weeks on 1 mg; 2 mg weekly is the maximum [3]. For the kidney indication, the label directs an increase to 1 mg after at least 4 weeks on 0.5 mg [3].

A missed dose can be given within 5 days; otherwise it is skipped [3]. The label allows changing the day of the week as long as the two doses are more than 48 hours apart [3]. When Ozempic is used with insulin, the two are given as separate injections and never mixed [3]. The Ozempic injection label warns that sharing a pen, even with a new needle, can transmit blood-borne infections [3].

What the blood-sugar trials show

The Ozempic label summarizes the SUSTAIN program. As monotherapy over 30 weeks, HbA1c fell 1.4 points on 0.5 mg and 1.6 points on 1 mg, against 0.1 points on placebo, from a baseline around 8.0 to 8.1; HbA1c below 7% was reached by 73% and 70% of those two groups versus 28% on placebo [3].

In SUSTAIN FORTE, 961 adults with type 2 diabetes on metformin and an HbA1c of 8.0 to 10.0% received 2 mg or 1 mg weekly for 40 weeks, and weight changed by −6.9 kg on 2 mg versus −6.0 kg on 1 mg [8]. The Ozempic injection label reports HbA1c reductions of 2.1 versus 1.9 points and HbA1c below 7% in 64% versus 56% [3].

What the cardiovascular and kidney trials show

SUSTAIN-6 randomized 3,297 adults with type 2 diabetes, 83% of whom had established cardiovascular disease, chronic kidney disease or both, to semaglutide 0.5 mg or 1 mg weekly or placebo for 104 weeks. The composite of cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 6.6% versus 8.9% (hazard ratio 0.74, 95% CI 0.58 to 0.95); non-fatal stroke was 1.6% versus 2.7% [9]. Retinopathy complications were more frequent on semaglutide (hazard ratio 1.76, 95% CI 1.11 to 2.78), and the label notes that rapid improvement in glucose control can temporarily worsen diabetic retinopathy [3][9].

The FLOW trial enrolled 3,533 adults with type 2 diabetes and chronic kidney disease and compared Ozempic 1 mg weekly with placebo. It stopped early at a planned interim analysis. The composite of kidney failure, at least 50% eGFR decline, or kidney or cardiovascular death occurred in 18.7% versus 23.2% (hazard ratio 0.76, 95% CI 0.66 to 0.88), and all-cause death was 12.8% versus 15.8% [10]. This trial underpins the kidney indication.

Does Ozempic cause weight loss?

Neither Ozempic injection nor Ozempic tablets is approved for weight loss [3][4]. Weight fell modestly in the diabetes trials — 6.9 kg versus 6.0 kg in SUSTAIN FORTE [8], and 4.6 versus 2.3 kg and 6.5 versus 3.0 kg in SUSTAIN 7, which compared semaglutide 0.5 mg and 1 mg with dulaglutide 0.75 mg and 1.5 mg over 40 weeks [11].

The large weight numbers come from trials of the 2.4 mg Wegovy dose, not Ozempic's 0.5 to 2 mg range. In STEP 1, 1,961 adults with obesity or overweight and no diabetes received 2.4 mg weekly or placebo for 68 weeks; mean weight change was −14.9% versus −2.4%, and 86.4% versus 31.5% lost at least 5% [5].

What the common side effects are

In the Ozempic label's pooled placebo-controlled diabetes trials (mean 32.9 weeks), nausea occurred in 6.1% on placebo, 15.8% on 0.5 mg and 20.3% on 1 mg; vomiting 2.3%, 5% and 9.2%; diarrhea 1.9%, 8.5% and 8.8%; abdominal pain 4.6%, 7.3% and 5.7%; constipation 1.5%, 5% and 3.1% [3]. Any gastrointestinal reaction occurred in 15.3%, 32.7% and 36.4%, and treatment was stopped for gastrointestinal reasons in 0.4%, 3.1% and 3.8% [3].

The label's warnings cover acute pancreatitis (stop if suspected), acute gallbladder disease, hypoglycemia when combined with insulin or a sulfonylurea, acute kidney injury from volume depletion, severe gastrointestinal reactions, hypersensitivity including anaphylaxis and angioedema, diabetic retinopathy complications, and pulmonary aspiration during general anesthesia or deep sedation — patients are told to inform healthcare providers of planned surgeries [3]. Ozempic is not recommended in patients with severe gastroparesis [3].

The boxed warning and contraindications

Semaglutide caused dose- and treatment-duration-dependent thyroid C-cell tumors in rodents at clinically relevant exposures. Whether it causes thyroid C-cell tumors, including medullary thyroid carcinoma, in humans is unknown [3]. Ozempic is contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, and in people with a prior serious hypersensitivity reaction to semaglutide or any excipient in the product [3]. The label lists neck mass, trouble swallowing, shortness of breath and persistent hoarseness as symptoms of thyroid tumors, and says routine calcitonin monitoring or thyroid ultrasound is of uncertain value [3].

What about compounded semaglutide?

FDA says compounded drugs are not FDA approved and are not reviewed for safety, effectiveness or quality before marketing [14]. As of May 31, 2026, FDA had received 990 adverse event reports for compounded semaglutide and says this likely undercounts; it also reports dosing errors with compounded injectable semaglutide and states that semaglutide sodium and semaglutide acetate salts are different active ingredients from the approved drug, with no lawful basis for use in compounding that it is aware of [14]. On April 30, 2026, FDA proposed to exclude semaglutide from the list of bulk substances outsourcing facilities may compound with, finding no clinical need; no final decision has been made [15].