The same active ingredient
Read the description sections of the two labels side by side and they match word for word: semaglutide, a GLP-1 analogue whose peptide backbone is made by yeast fermentation, with a fatty acid chain at position 26 that binds it to albumin and a change at position 8 that protects it from the enzyme DPP-4 [1][2].
So the question is not which molecule is different, but which label applies. A label sets out who a product is approved for, at which doses, in which devices and with which precautions. Those are the parts that differ, and they are what the rest of this article compares.
Row by row: the two injection labels
Every cell below comes from the current US label of that product; the section number is in the first column [1][2]. The EU row comes from the European product information [5][6].
| Label item | Ozempic® injection | Wegovy® injection |
|---|---|---|
| Approved uses (section 1) | Blood sugar control in adults with type 2 diabetes; lowering major cardiovascular events in those with heart disease; lowering kidney decline and cardiovascular death in those with chronic kidney disease [1] | Lowering major cardiovascular events in adults with heart disease and obesity or overweight; weight reduction and maintenance; MASH with moderate to advanced fibrosis (accelerated approval) [2] |
| Ages covered (section 1) | Adults [1] | Adults; for weight, also ages 12 and older [2] |
| Highest weekly dose (section 2.2) | 2 mg [1] | 7.2 mg for weight reduction in adults who tolerated 2.4 mg for at least 4 weeks [2] |
| Devices (section 3) | Multi-dose pens and single-dose prefilled syringes [1] | Single-dose pens, single-dose syringes and a FlexTouch® pen holding four 2.4 mg doses [2] |
| Bioavailability and peak (section 12.3) | 89%; peak 1 to 3 days after a dose [1] | 89%; peak 1 to 3 days after a dose [2] |
| Half-life (section 12.3) | About 1 week [1] | About 1 week [2] |
| Still circulating after the last dose (section 12.3) | About 5 weeks [1] | About 5 to 7 weeks after 2.4 mg or 7.2 mg [2] |
| Steady state (section 12.3) | Reached after 4 to 5 weeks of weekly doses [1] | Average levels given; no time stated [2] |
| Heart rate (sections 5 and 6) | Mean rise of 2 to 3 beats per minute, reported among adverse reactions [1] | Own warning (5.9); mean rise of 1 to 4 beats per minute [2] |
| Planned pregnancy (section 8.3) | Stop at least 2 months before [1] | Stop at least 2 months before, for weight and heart use; for MASH, weighed case by case [2] |
| In the EU (section 4.1) | Type 2 diabetes only; heart and kidney results described in 5.1 [5] | Weight management in adults and adolescents 12+ over 60 kg; 7.2 mg for adults starting at a BMI of 30 or more [6] |
Do the milligrams mean the same thing here?
For these two injections, largely yes: the same molecule is given the same way and both labels report the same absorption and timing [1][2]. One milligram from an Ozempic® pen and one milligram from a Wegovy® pen is the same amount of semaglutide.
That still does not make the pens interchangeable. The products differ in devices, strengths, inactive ingredients and approved uses, neither label describes moving from one brand to the other, and the Wegovy® label advises against combining it with any other semaglutide product [1][2]. The tablets are a different story again, because so little of a swallowed dose is absorbed [3].
What the trials behind each label measured
Each label rests on its own trials, run in different people with different goals. The table sets one key trial from each label under the same headings to show what was measured, not how much changed. These are separate studies, so their results are not placed side by side here [1][2].
| Heading | Ozempic® monotherapy trial (section 14.1) | Wegovy® Study 2 (section 14.2) |
|---|---|---|
| Who took part | 388 adults with type 2 diabetes managed with diet and exercise [1] | 1,961 adults with obesity, or overweight plus a weight-related condition, without diabetes [2] |
| How long | 30 weeks [1] | 68 weeks [2] |
| Main measure | Change in HbA1c [1] | Percent change in body weight [2] |
| Compared with | Placebo [1] | Placebo [2] |
The trial that gave both doses
STEP 2 is the closest the published evidence comes to a direct look. It enrolled 1,210 adults with type 2 diabetes and a BMI of at least 27 and randomly gave them weekly semaglutide 2.4 mg, semaglutide 1.0 mg (described in the paper as the dose approved for diabetes) or placebo for 68 weeks, alongside lifestyle support [4].
The abstract does not report the weight result for the 1.0 mg arm, and the Wegovy® label shows this trial (its Study 3) only against placebo, so the two doses cannot be compared on weight from these sources [2][4]. Any adverse event was reported by 87.6% on 2.4 mg, 81.8% on 1.0 mg and 76.9% on placebo, and gut-related events, mostly mild to moderate, by 63.5%, 57.5% and 34.3% [4]. The trial was funded by Novo Nordisk and compared two doses of one molecule, not two branded products.
Side-effect tables: same rows, different trials
Each label has a table of reactions that were common and more frequent than on placebo. The rows below use the same five reactions from both tables. The Ozempic® pool comes from 2 placebo-controlled trials in type 2 diabetes with an average of about 33 weeks on the drug; the Wegovy® pool from 3 trials in 2,116 adults with obesity or overweight treated for up to 68 weeks [1][2].
- The populations, doses and trial lengths differ, and even the placebo rates differ, so the two columns in the table below are not a ranking [1][2].
- The Ozempic® label notes that most nausea, vomiting and diarrhoea happened while the dose was being raised [1].
- Beyond the five reactions in the table, the Wegovy® list of common reactions is longer, and includes headache, fatigue, dizziness, a skin-sensation change called dysesthesia and hair loss [2].
| Reaction | Ozempic®: placebo / 0.5 mg / 1 mg | Wegovy®: placebo / 2.4 mg |
|---|---|---|
| Nausea | 6.1 / 15.8 / 20.3 [1] | 16 / 44 [2] |
| Diarrhoea | 1.9 / 8.5 / 8.8 [1] | 16 / 30 [2] |
| Vomiting | 2.3 / 5 / 9.2 [1] | 6 / 24 [2] |
| Constipation | 1.5 / 5 / 3.1 [1] | 11 / 24 [2] |
| Abdominal pain | 4.6 / 7.3 / 5.7 [1] | 10 / 20 [2] |
The tablets are separate products
There is now an Ozempic® tablet as well, but it sits in a different label: the one shared with Rybelsus®, for type 2 diabetes. That label says Rybelsus® and Ozempic® tablets are not substitutable milligram for milligram [3].
Wegovy® tablets are covered by the Wegovy® label and come in four strengths: 1.5, 4, 9 and 25 mg [2]. Ozempic® tablets share the first three numbers, but they sit in a different label with different uses and maintenance doses [2][3]. All of these tablets are taken once a day on an empty stomach in the morning with a small amount of water, then a wait of at least 30 minutes before food, drink or other oral medicines [2][3].
Missed doses and changing the day
- Ozempic® injection: a missed dose can be taken within 5 days; after that it is skipped. The weekly day can change as long as at least 2 days separate two doses [1].
- Wegovy® injection: if the next dose is more than 2 days away, the missed dose is taken as soon as possible; if it is less than 2 days away, it is skipped. If 2 or more doses in a row are missed, the label says to restart the dose steps at a lower dose [2].
- Wegovy® tablets and Ozempic® tablets: a missed tablet is skipped and the next one taken the following day [2][3].
Warnings both labels carry
Both labels share the boxed warning about thyroid C-cell tumours in rodents and the warnings on pancreatitis, gallbladder disease, low blood sugar with insulin or sulfonylureas, kidney injury from dehydration, severe stomach reactions, allergic reactions, diabetic eye complications and aspiration during anaesthesia or deep sedation [1][2].
Both also warn never to share a multi-dose pen between people, even with a new needle: every Ozempic® pen, and the Wegovy® FlexTouch® pen [1][2].
Not to be combined, and no bridge between them
The Wegovy® label says using it with other semaglutide-containing products or any other GLP-1 receptor agonist is not recommended [2]. In practice that means Ozempic® and Wegovy® are not meant to be used together, and moving from one to the other is something your prescriber plans.
Neither label gives a schedule for that move. The only switch the Wegovy® label describes is between its own injection and its own tablets [2]. Because semaglutide stays in the circulation for weeks after the last dose, a change does not start from zero [1][2].
Ozempic®, Wegovy® and Rybelsus® are registered trademarks of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
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