How Long Does Ozempic Take to Work?

Semaglutide starts working on appetite within the first weeks, but the first month is a low starter dose meant to limit nausea, not to cause much weight loss. The Wegovy dose is raised every 4 weeks and reaches the full 2.4 mg maintenance dose at week 17. In the 68-week STEP 1 trial, people on semaglutide 2.4 mg lost 14.9% of their body weight on average versus 2.4% on placebo. Semaglutide has a half-life of about one week, so it stays in your blood for about 5 to 7 weeks after the last dose.

By Kymata Labs Editorial · Published Oct 11, 2026 · Updated Oct 11, 2026 · How we rank

Facts checked Oct 11, 2026 · Medical review pending

Quick answer

Appetite: in a 12-week trial, semaglutide 1 mg cut how much people chose to eat at buffet meals by 24% versus placebo, with less hunger and fewer cravings (grade B).
First month: the 0.25 mg starting dose is for getting used to the drug; the Ozempic label says to raise it to 0.5 mg after 4 weeks, and Wegovy reaches 2.4 mg at week 17.
Weight loss: STEP 1 averaged 14.9% at 68 weeks on Wegovy 2.4 mg versus 2.4% on placebo; 86% of people lost at least 5% (grade A).
Leaving your system: half-life about 1 week; still in the blood about 5 weeks after the last Ozempic dose and 5 to 7 weeks after the last Wegovy 2.4 mg or 7.2 mg dose, per the labels.

Week-by-week: the Wegovy dose ladder

If side effects are hard to tolerate, the label lets the prescriber delay the next step by 4 weeks, so your own timeline may be slower. That is normal and does not mean the drug is failing.

Wegovy injection starting dose and escalation, from the FDA label (DailyMed, revised 06/2026). Ozempic for diabetes starts the same way, 0.25 mg for 4 weeks then 0.5 mg, with a maximum of 2 mg.
Weeks	Weekly dose	What to expect
1-4	0.25 mg	Starter dose to limit stomach side effects; appetite may start to change
5-8	0.5 mg	Dose escalation; nausea is most common during escalation
9-12	1 mg	Dose escalation
13-16	1.7 mg	Dose escalation
17 onward	2.4 mg (or 1.7 mg)	Maintenance; a prescriber may later raise it to 7.2 mg (Wegovy HD) after at least 4 weeks at 2.4 mg

How much weight, and by when

STEP 1 (Wegovy 2.4 mg, adults without diabetes): 14.9% average loss at 68 weeks vs 2.4% on placebo; 69% lost at least 10% and 50% lost at least 15%.
Higher dose: in the label’s 72-week Study 8, Wegovy HD 7.2 mg averaged 18.8% versus 15.5% on 2.4 mg and 3.9% on placebo.
People with type 2 diabetes lose less on average. In the label’s 72-week Study 9 in people with diabetes, 7.2 mg averaged 13.2%.
Ozempic doses (0.5 to 2 mg) are lower than Wegovy’s 2.4 mg, so expect less weight loss at Ozempic doses than the Wegovy trial figures.

How long it lasts after you stop

With a half-life of about one week, most of the drug is gone within 5 to 7 weeks, and appetite usually returns. In STEP 4, people who switched to placebo after 20 weeks regained 6.9% of body weight over the next 48 weeks, while those who stayed on semaglutide lost another 7.9%. In the STEP 1 extension, people had regained about two-thirds of their lost weight one year after stopping.

The Wegovy label also says to stop at least 2 months before a planned pregnancy because of the long half-life.

FAQ

How long does it take for Ozempic to suppress appetite?

Many people notice less hunger in the first weeks, but the first 4 weeks are a 0.25 mg starter dose. In a 12-week trial, semaglutide 1 mg reduced how much people ate at self-serve meals by 24% versus placebo, with less hunger and fewer food cravings.

How much weight can you lose in the first month on Ozempic or Wegovy?

Usually only a little, because the first month is a 0.25 mg starter dose to limit nausea. Most weight loss happens after the dose is raised; in the STEP 1 trial the average loss on Wegovy 2.4 mg reached 14.9% at 68 weeks.

How long does Ozempic stay in your system?

Semaglutide has a half-life of about one week. The Ozempic label says it stays in the blood for about 5 weeks after the last dose, and the Wegovy label says about 5 to 7 weeks after the last 2.4 mg or 7.2 mg dose.

Is Ozempic not working if I have not lost weight after 4 weeks?

Not necessarily. The 0.25 mg starting dose is not meant to produce much weight loss, and Wegovy only reaches its 2.4 mg maintenance dose at week 17. Talk to your prescriber about your dose schedule rather than judging the drug on the first month.

How long does Zepbound take to work compared with Ozempic?

Zepbound (tirzepatide) also starts at a low dose (2.5 mg) and steps up every 4 weeks. Its half-life is about 5 days. In SURMOUNT-1, people on 15 mg lost 20.9% at 72 weeks versus 3.1% on placebo, and in a 72-week head-to-head trial tirzepatide averaged 20.2% versus 13.7% for semaglutide.

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Sources

Facts on this page come from the sources below, read Oct 11, 2026. We link only to sellers we have an affiliate relationship with and to government and research sources; other sellers' prices are quoted as plain text.