Ozempic results are the blood sugar and body weight changes measured in the clinical trials described in the FDA label for Ozempic (semaglutide) injection.
- FDA-approved for
- Type 2 diabetes, heart and kidney risk reduction in T2D [1]
- A1C drop (2 mg, 40 weeks)
- 2.1 points vs 1.9 on 1 mg [1]
- Weight change (2 mg, 40 weeks)
- Average 6.4 kg vs 5.6 kg on 1 mg [1]
- Half-life
- About 1 week; in the body about 5 weeks after the last dose [1]
- Weight-loss sibling
- Wegovy: 14.9% average loss at 68 weeks in STEP 1 [3]
How Ozempic works in the body
Ozempic contains semaglutide, a GLP-1 receptor agonist. It increases insulin release and lowers glucagon in a glucose-dependent way, so the effect is strongest when blood sugar is high [1]. It also causes a minor delay in how fast food leaves the stomach [1]. The label's main measure of success is A1C, a blood test that reflects average blood sugar over about three months. Weight loss is not a labeled outcome, though the trials did record weight.
Ozempic's label covers three uses, all in adults with type 2 diabetes: blood sugar control, lowering the risk of major heart events in people with heart disease, and lowering the risk of kidney decline, kidney failure and cardiovascular death in people with chronic kidney disease [1]. For the class-wide picture, see how GLP-1 medicines work.
Is Ozempic approved for weight loss?
No. Weight loss is not one of Ozempic's labeled uses [1]. When a clinician prescribes Ozempic only to lose weight, that is off-label use, and insurers usually treat it differently. Wegovy contains the same active ingredient and is approved to reduce excess body weight and keep it off long term [2]. In the STEP 1 trial, adults without diabetes on Wegovy's 2.4 mg dose lost an average of 14.9% of body weight at 68 weeks, vs 2.4% on placebo [3]. Those results apply to Wegovy's doses and population, not to Ozempic. The Ozempic vs Wegovy comparison covers the differences.
What the Ozempic trials found
| Trial (length) | Comparator | A1C change on Ozempic | Weight change on Ozempic |
|---|---|---|---|
| Monotherapy (30 weeks) | Placebo: A1C -0.1, weight -1.2 kg | -1.4 (0.5 mg), -1.6 (1 mg) | -3.8 kg (0.5 mg), -4.7 kg (1 mg) |
| vs sitagliptin (56 weeks) | Sitagliptin: A1C -0.7, weight -1.7 kg | -1.3 (0.5 mg), -1.5 (1 mg) | -4.2 kg (0.5 mg), -5.5 kg (1 mg) |
| vs exenatide ER (56 weeks) | Exenatide ER: A1C -0.9, weight -2.0 kg | -1.4 (1 mg) | -4.8 kg (1 mg) |
| vs insulin glargine (30 weeks) | Glargine: A1C -0.9, weight +0.9 kg | -1.2 (0.5 mg), -1.5 (1 mg) | -3.2 kg (0.5 mg), -4.7 kg (1 mg) |
| Add-on to basal insulin (30 weeks) | Placebo: A1C -0.2, weight -1.2 kg | -1.3 (0.5 mg), -1.7 (1 mg) | -3.5 kg (0.5 mg), -6.0 kg (1 mg) |
| 2 mg vs 1 mg (40 weeks) | 1 mg: A1C -1.9, weight -5.6 kg | -2.1 (2 mg) | -6.4 kg (2 mg) |
In the SUSTAIN 6 heart outcomes trial, major cardiovascular events occurred in 6.6% of people on Ozempic vs 8.9% on placebo (hazard ratio 0.74) [1]. In the FLOW kidney trial, Ozempic 1 mg lowered the combined risk of kidney decline, kidney failure and kidney or cardiovascular death (hazard ratio 0.76) [1].
How long Ozempic takes to work
The label does not name a day when Ozempic starts working. Its trials measured A1C and weight at 30 to 56 weeks [1]. Treatment starts at 0.25 mg once weekly for 4 weeks, then 0.5 mg, with any further increase after at least 4 weeks on the current dose [1]. Following that schedule, the earliest week a person could reach 2 mg is week 13. Appetite changes are not timed in the label. Your prescriber will usually judge progress with A1C tests and your weight over months, not days. The Ozempic dosage page has the full schedule.
How long Ozempic stays in your system
Semaglutide's elimination half-life is about 1 week, and it stays in circulation for about 5 weeks after the last dose [1]. The 0.5 mg and 2 mg doses share that half-life; dose does not change it in the label. Because of the long washout, the label says to stop Ozempic at least 2 months before a planned pregnancy [1].
Why some people lose less, or gain
Trial numbers are averages, so some people lose more and some lose less. Even with Wegovy's higher weight-loss dose in STEP 1, 86.4% of people lost at least 5% of their weight, which means about 1 in 7 did not [3]. Ozempic's top dose is 2 mg, and moving from 1 mg to 2 mg added only 0.8 kg of average loss, a difference that was not statistically significant [1]. If weight is your main goal, ask your prescriber whether a medicine labeled for weight management fits better, such as Wegovy or Zepbound. Other medicines, including insulin, can push weight up; in one trial, people on insulin glargine gained an average of 0.9 kg [1]. Eating habits on treatment are covered in what to eat on Ozempic, and the tirzepatide comparison is on Mounjaro results.
Safety, age limits and how long people stay on it
The label states that safety and effectiveness in children have not been established [1], so Ozempic is not labeled for a 16-year-old. Wegovy injection, by contrast, is labeled for weight reduction from age 12 [2]. Semaglutide's first US approval was in 2017 [4]. No maximum treatment length is set in the Ozempic label. The thyroid C-cell tumor boxed warning and the warnings on pancreatitis, gallbladder disease and kidney injury are covered on Ozempic side effects, and dose-day rules on how to use Ozempic.
Ozempic's label does not report muscle or bone changes. In a tirzepatide trial substudy, about 25% of weight lost was lean mass [5], which is a reason to keep up protein and strength work; see how to keep muscle on a GLP-1. After people stopped semaglutide 2.4 mg in the STEP 1 extension, they regained about two-thirds of the weight they had lost within a year [6]. More on that in what happens when you stop Ozempic.
Before you start
Do not use Ozempic if you or a family member has had medullary thyroid carcinoma or MEN 2 [1]. Severe stomach pain that will not go away needs a call to your prescriber right away, because pancreatitis has been reported [1]. With insulin or a sulfonylurea, low blood sugar becomes more likely [1]. Call 911 for trouble breathing or swelling of the face or throat.
Prices change often. NovoCare lists Ozempic self-pay at $349 a month for 0.25, 0.5 or 1 mg and $499 for 2 mg, with a $199 offer for the first two fills of the starter doses through December 31, 2026 (checked October 17, 2026) [7]. Details and insurance routes are on Ozempic cost.
Questions people ask
How does Ozempic work?
Ozempic (semaglutide) is a GLP-1 receptor agonist. It raises insulin and lowers glucagon when blood sugar is high and slightly slows stomach emptying [1].
Is Ozempic FDA approved for weight loss?
How much weight do people lose on Ozempic?
In Ozempic's diabetes trials, average weight loss ranged from 3.2 kg to 6.4 kg depending on dose and trial; the 2 mg dose averaged 6.4 kg at 40 weeks [1]. These are averages, not a promise.
How long does it take for Ozempic to work?
The label gives no start date. Treatment begins at 0.25 mg weekly for 4 weeks, and trials measured A1C and weight at 30 to 56 weeks [1].
How long does Ozempic stay in your system?
Semaglutide has a half-life of about 1 week and remains in circulation for about 5 weeks after the last dose [1].
Why am I not losing weight on Ozempic?
How long has Ozempic been around?
Semaglutide was first approved in the US in 2017, according to the initial approval year on its FDA label [4].
Can a 16-year-old take Ozempic for weight loss?
Do you gain weight back after Ozempic?
Ozempic's label has no stopping data. In the STEP 1 extension of semaglutide 2.4 mg, people regained about two-thirds of their lost weight within a year of stopping [6].
Sources
7 cited
- Ozempic (semaglutide) injection prescribing information. DailyMed, U.S. National Library of Medicine, May 2026.
- Wegovy (semaglutide) injection and tablets prescribing information. DailyMed, U.S. National Library of Medicine, Jun 2026.
- STEP 1 trial of semaglutide 2.4 mg in adults with overweight or obesity (Wilding et al., NEJM 2021), PubMed record. PubMed, National Library of Medicine, Feb 10, 2021.
- Wegovy structured product label (FDALabel). U.S. Food and Drug Administration, Jun 18, 2026.
- SURMOUNT-1 body composition substudy (Look et al., Diabetes Obes Metab 2025), PubMed record. PubMed, National Library of Medicine, Feb 25, 2025.
- STEP 1 trial extension: weight regain after stopping semaglutide (Wilding et al., Diabetes Obes Metab 2022), PubMed record. PubMed, National Library of Medicine, May 19, 2022.
- Ozempic self-pay and savings offers. NovoCare (Novo Nordisk), Oct 17, 2026.
This page is general information, not medical advice. Talk with a licensed clinician about your own care.