Not losing weight on GLP-1 medication is more common than ads suggest. In the main obesity trials, about 1 in 7 people on semaglutide 2.4 mg and 9% to 15% on tirzepatide lost less than 5% of their body weight.[1][2] Lower doses, type 2 diabetes, early dose escalation and other weight-gaining medicines are the usual explanations.
This guide covers semaglutide (Ozempic, Wegovy; see our semaglutide profile) and tirzepatide (Mounjaro, Zepbound; see the tirzepatide profile). For background on the drug class, visit the GLP-1 basics hub.
How many people don’t respond?
Weight loss varies widely, even in tightly run trials. Researchers often use 5% of starting weight as the threshold for a meaningful response.
| Trial | Drug and dose | Average loss | Reached 5% or more |
|---|---|---|---|
| STEP 1 (no diabetes) | Semaglutide 2.4 mg | 14.9% | 86.4%[1] |
| SURMOUNT-1 (no diabetes) | Tirzepatide 5 / 10 / 15 mg | 15.0% / 19.5% / 20.9% | 85% / 89% / 91%[2] |
| STEP 2 (type 2 diabetes) | Semaglutide 2.4 mg | 9.6% | 68.8%[3] |
| SURMOUNT-2 (type 2 diabetes) | Tirzepatide 10 / 15 mg | 12.8% / 14.7% | 79% to 83%[4] |
Put the other way, about 13.6% of people on semaglutide in STEP 1 and roughly 3 in 10 in STEP 2 did not reach 5%.[1][3] An average is not a promise. In STEP 1, the placebo group also followed a lifestyle program and 31.5% of them reached 5%; in SURMOUNT-1, 35% on placebo did. Individual results vary widely in both directions.[1][2] For the full range of results, see our guides to semaglutide weight loss results and tirzepatide weight loss results.
Are you on a weight-loss dose?
Dose matters, and the brands are dosed differently.
- Ozempic is approved for type 2 diabetes, with maintenance doses of 0.5 mg, 1 mg or 2 mg weekly chosen for blood sugar control.[6]
- Wegovy injection for weight reduction has a maintenance dose of 1.7 mg or 2.4 mg (2.4 mg recommended). People who tolerate 2.4 mg for at least 4 weeks can go up to 7.2 mg if more weight loss is clinically needed.[7]
- Zepbound has maintenance doses of 5 mg, 10 mg or 15 mg. In SURMOUNT-1, average loss rose with dose, from 15.0% at 5 mg to 20.9% at 15 mg.[8][2]
STEP 2 compared semaglutide 2.4 mg with 1.0 mg, which it called the dose approved for diabetes treatment, because the weight-loss dose is higher.[3] In real-world care, lower doses are common. In a 2025 health-system study of 7,881 people without diabetes, 80.8% were on low maintenance doses, and average 1-year weight loss was 8.7%. The authors linked this to stopping treatment and low doses.[11]
Doses go up gradually, usually every 4 weeks, to limit nausea. Your clinician sets the pace. For maintenance dose details, see semaglutide maintenance dose and tirzepatide maintenance dose.
Type 2 diabetes and lower response
People with type 2 diabetes lose less weight on the same drug. Semaglutide 2.4 mg produced 14.9% loss without diabetes but 9.6% with it.[1][3] Tirzepatide 15 mg produced 20.9% without diabetes and 14.7% with it.[2][4] Those smaller numbers are still well above placebo (3.4% and 3.2%), so lower loss in diabetes is expected, not necessarily a failure.[3][4]
Timing and plateaus
Weight loss in the first weeks can be small, because treatment starts at low doses that are not approved as maintenance doses. Wegovy steps up over 16 weeks before reaching 2.4 mg, and Zepbound rises in 2.5 mg steps after at least 4 weeks on each dose.[7][8] In SURMOUNT-1, dose escalation alone took 20 weeks.[2]
Plateaus are normal. In STEP 5, a 2-year trial, weight loss on semaglutide 2.4 mg leveled off after about week 60 and then held steady, ending at 15.2% at week 104.[5] The authors noted the same leveling around week 60 in the 68-week trials.[5] If your weight stops falling after a year or more, you may simply have reached your plateau. A plateau on the drug is different from regain: in STEP 5, people who stayed on semaglutide held their loss through week 104.[5] Judging progress by waist size, blood pressure, blood sugar and how you feel, not only the scale, gives a fuller picture.
Medicines that can work against you
Many common prescriptions can cause weight gain. The Endocrine Society’s obesity drug guideline recommends choosing medicines with favorable weight effects where possible.[10] Classes it links to weight gain include:
| Category | Examples linked to weight gain[10] |
|---|---|
| Diabetes | Insulin, sulfonylureas, glinides, thiazolidinediones such as pioglitazone |
| Antidepressants | Amitriptyline, mirtazapine, paroxetine |
| Antipsychotics | Olanzapine, clozapine, quetiapine, risperidone |
| Seizure and nerve-pain drugs | Valproate, gabapentin, pregabalin, carbamazepine |
| Steroids | Glucocorticoids such as prednisone |
| Blood pressure | Some beta-blockers, such as metoprolol |
| Contraception | Injectable progestin-only methods |
Never stop a prescribed medicine on your own. A clinician may be able to suggest an alternative with less effect on weight. The same guideline notes that some medicines have the opposite effect and can support weight loss, which a prescriber can weigh when choosing treatments for other conditions.[10]
When is it time to reassess?
The labels handle this differently:
- Saxenda (liraglutide): check weight after 16 weeks and stop if an adult has not lost at least 4%, since meaningful long-term loss is unlikely.[9]
- Wegovy and Zepbound: no fixed cutoff. The labels say to consider treatment response and tolerability when choosing the maintenance dose.[7][8]
What clinicians typically review
If weight loss is slow, a clinician may look at:
- Dose and time on treatment: whether you have reached a maintenance dose and stayed on it long enough.
- Missed or delayed doses: gaps can mean restarting at a lower dose.[7]
- Other medicines: anything from the table above.[10]
- Diabetes status: expectations are lower with type 2 diabetes.[3]
- Eating pattern and protein intake: our GLP-1 diet guide covers this.
- Alcohol: drinks add calories; see GLP-1 and alcohol.
If you are thinking about coming off the drug instead, read what happens when you stop a GLP-1 first.
