How Much Weight Do You Lose on Semaglutide? Results by Dose and Type

In the STEP 1 trial, adults with overweight or obesity who took 2.4 mg of semaglutide once weekly lost an average of 14.9% of their body weight over 68 weeks, or 15.3 kg (about 34 lb), compared with 2.4% (2.6 kg) for people on placebo ^[1]. That is the number most often quoted as “the” semaglutide result, but it is really the result for one dose, one formulation, and one group of people: adults without diabetes, taking the weekly injection, alongside structured lifestyle counseling ^[1].

There is no single average. The answer changes with the dose, the formulation (weekly injection versus daily pill), how long treatment lasts, whether the person has type 2 diabetes, and how much lifestyle support is bundled with the drug ^{[1][2][3][6][7]}. For context on who is taking what: semaglutide is approved, at doses up to 1 mg once weekly by injection, for type 2 diabetes in adults and for reducing the risk of cardiovascular events in people with type 2 diabetes and cardiovascular disease ^[1]. The 2.4 mg weekly injection is approved for weight management in the United States, Europe, the United Kingdom and Canada, for adults with a BMI of 30 or higher, or 27 or higher with at least one weight-related comorbidity ^[2]. The weight-loss results below come mostly from the STEP (Semaglutide Treatment Effect in People with obesity) phase 3 program and its related trials.

Trial	Treatment	Duration	Mean weight change (drug)	Comparator	Comparator result
STEP 1 [1]	2.4 mg weekly injection	68 weeks	−14.9% (−15.3 kg)	Placebo	−2.4% (−2.6 kg)
STEP 5 [2]	2.4 mg weekly injection	104 weeks	−15.2%	Placebo	−2.6%
STEP 3 [3]	2.4 mg weekly injection + intensive behavioral therapy	68 weeks	−16.0%	Placebo + same therapy	−5.7%
STEP 8 [4]	2.4 mg weekly injection	68 weeks	−15.8%	Liraglutide 3.0 mg daily (primary comparison); pooled placebo	−6.4%; −1.9%
OASIS 1 [7]	50 mg daily pill	68 weeks	−15.1%	Placebo	−2.4%
OASIS 4 [6]	25 mg daily pill	64 weeks (71-week trial)	−13.6%	Placebo	−2.2%
REDEFINE 1 [8]	CagriSema (cagrilintide + semaglutide 2.4 mg)	68 weeks	−20.4%	Placebo	−3.0%

What was the average weight loss in the STEP 1 trial?

STEP 1 enrolled 1,961 adults at 129 sites in 16 countries and randomly assigned them 2:1 to semaglutide 2.4 mg weekly or placebo for 68 weeks, both plus lifestyle intervention ^[1]. To qualify, participants needed a BMI of 30 or higher, or 27 or higher with at least one treated or untreated weight-related condition such as hypertension, dyslipidemia, obstructive sleep apnea, or cardiovascular disease — and they could not have diabetes (HbA1c had to be below 6.5%) ^[1].

The mean weight change at week 68 was −14.9% with semaglutide versus −2.4% with placebo, a treatment difference of −12.4 percentage points (95% CI −13.4 to −11.5) ^[1]. In kilograms, that was −15.3 kg (about 34 lb) versus −2.6 kg, a difference of −12.7 kg (about 28 lb) ^[1].

The trial’s dose schedule started at 0.25 mg weekly and increased every 4 weeks to reach the 2.4 mg maintenance dose by week 16, with lower maintenance doses permitted for people who could not tolerate the full dose ^[1]. Lifestyle support included counseling every 4 weeks, a 500-calorie-per-day deficit diet, and a target of 150 minutes of physical activity per week ^[1]. Nausea and diarrhea were the most common side effects, typically transient and mild to moderate; 4.5% of the semaglutide group stopped treatment because of gastrointestinal events versus 0.8% of the placebo group ^[1].

How many people lost 5%, 10% or 15% of their body weight?

Averages hide the spread, so the trials also report how many people crossed each threshold. In STEP 1 at week 68 ^[1]:

• At least 5% weight loss: 86.4% (1,047 participants) on semaglutide versus 31.5% (182) on placebo
• At least 10%: 69.1% (838) versus 12.0% (69)
• At least 15%: 50.5% (612) versus 4.9% (28)

So about half of semaglutide users in STEP 1 lost 15% or more, and roughly 1 in 7 did not reach even 5% ^[1]. In OASIS 1, the oral 50 mg trial, the pattern was similar: 85% reached 5%, 69% reached 10%, 54% reached 15%, and 34% reached 20%, versus 26%, 12%, 6%, and 3% on placebo ^[7].

Does the weight loss last past one year?

Yes, at least through two years in the trial that ran longest. STEP 5 followed 304 adults (152 on semaglutide 2.4 mg, 152 on placebo, both with behavioral intervention) for 104 weeks, making it the longest semaglutide weight-management trial at the time of publication ^[2]. Mean weight change at week 104 was −15.2% with semaglutide versus −2.6% with placebo, a difference of −12.6 percentage points (95% CI −15.3 to −9.8) ^[2]. Of the semaglutide group, 77.1% had lost at least 5% of baseline weight at week 104, versus 34.4% of the placebo group ^[2].

The trial population was mostly female (77.6%) and white (93.1%), with a mean age of 47.3 years, mean weight of 106.0 kg, and mean BMI of 38.5 ^[2]. Not everyone stayed on the drug the whole time: 92.8% completed the trial, but 79.9% were still on treatment at the end-of-treatment visit — about a fifth had stopped ^[2]. Gastrointestinal adverse events occurred in 82.2% of the semaglutide group versus 53.9% of the placebo group, mostly mild to moderate ^[2].

Does adding intensive behavioral therapy change the results?

It raises the raw percentage but shrinks the gap over placebo. STEP 3 enrolled 611 US adults without diabetes at 41 sites and assigned them 2:1 to semaglutide 2.4 mg (n=407) or placebo (n=204) for 68 weeks; both groups got an 8-week initial low-calorie diet plus 30 counseling visits over the 68 weeks ^[3]. Mean weight change was −16.0% with semaglutide versus −5.7% with placebo, a difference of −10.3 percentage points (95% CI −12.0 to −8.6) ^[3].

Threshold results were 86.6% versus 47.6% for 5%, 75.3% versus 27.0% for 10%, and 55.8% versus 13.2% for 15% ^[3]. The participants averaged 46 years old, 105.8 kg, and BMI 38.0, and 81.0% were women ^[3].

Notice the trade-off: the semaglutide group lost more in STEP 3 (−16.0%) than in STEP 1 (−14.9%), but the placebo group also lost far more (−5.7% versus −2.4%) because of the intensive therapy. The placebo-subtracted difference was 12.4 percentage points in STEP 1 versus 10.3 in STEP 3 at week 68 ^[2]. Gastrointestinal adverse events occurred in 82.8% versus 63.2%, and 3.4% of the semaglutide group discontinued for gastrointestinal events versus 0% of the placebo group ^[3].

What were the results with oral semaglutide pills?

Two oral doses have been studied for weight management: 25 mg and 50 mg once daily ^[6][7].

OASIS 1, a phase 3 trial at 50 clinics in nine countries, randomly assigned 667 adults (334 to drug, 333 to placebo) to oral semaglutide 50 mg or placebo for 68 weeks ^[7]. Mean weight change at week 68 was −15.1% (SE 0.5) versus −2.4% (SE 0.5), a difference of −12.7 percentage points (95% CI −14.2 to −11.3) ^[7]. Gastrointestinal adverse events, mostly mild to moderate, occurred in 80% of the drug group versus 46% of the placebo group ^[7].

OASIS 4, indexed as a phase 2 trial, tested the 25 mg daily dose in a 71-week double-blind study at 22 sites in four countries, with coprimary endpoints measured at week 64; 205 participants got the drug and 102 got placebo ^[6]. Eligibility matched the injection trials: no diabetes, BMI of 30 or higher, or 27 or higher with at least one obesity-related complication ^[6]. Mean weight change to week 64 was −13.6% versus −2.2%, a difference of −11.4 percentage points (95% CI −13.9 to −9.0) ^[6]. Gastrointestinal adverse events occurred in 74.0% versus 42.2% ^[6].

These pill-versus-shot numbers come from separate trials in different populations, so they are not head-to-head evidence that one formulation beats the other.

How does semaglutide compare with liraglutide?

STEP 8 was a 68-week, open-label phase 3b trial at 19 US sites comparing semaglutide 2.4 mg weekly (n=126) with liraglutide 3.0 mg daily (n=127) in 338 adults without diabetes, with a pooled placebo group (n=85) ^[4]. Mean weight change was −15.8% with semaglutide versus −6.4% with liraglutide, a difference of −9.4 percentage points (95% CI −12.0 to −6.8); pooled placebo was −1.9% ^[4].

Threshold results favored semaglutide across the board: at least 10% loss in 70.9% versus 25.6%, at least 15% in 55.6% versus 12.0%, and at least 20% in 38.5% versus 6.0% ^[4]. Fewer semaglutide participants discontinued treatment for any reason (13.5% versus 27.6%), while gastrointestinal adverse events were similar (84.1% versus 82.7%) ^[4]. The semaglutide arm used a 16-week dose escalation versus 4 weeks for liraglutide, and participants who could not tolerate 2.4 mg could use 1.7 mg ^[4]. Because the active-treatment comparison was open-label — participants knew which drug they were getting — the results are not blinded in the way the placebo comparisons are ^[4].

What about the cagrilintide combination (CagriSema)?

REDEFINE 1, a phase 3a trial, randomly assigned 3,417 adults without diabetes (BMI 30 or higher, or 27 or higher with a complication) in a 21:3:3:7 ratio to CagriSema (semaglutide 2.4 mg plus cagrilintide 2.4 mg, n=2,108), semaglutide 2.4 mg alone (n=302), cagrilintide alone (n=302), or placebo (n=705) for 68 weeks ^[8]. Mean weight change with CagriSema was −20.4% versus −3.0% with placebo, a difference of −17.3 percentage points (95% CI −18.1 to −16.6) ^[8]. Confirmatory secondary endpoints included weight loss of 20%, 25%, and 30% or more ^[8]. Gastrointestinal adverse events occurred in 79.6% of the CagriSema group versus 39.9% of the placebo group, mainly transient and mild to moderate ^[8].

One caution on these numbers. The cited report gives a figure for CagriSema and for placebo but does not report the mean percentage change for the semaglutide-alone arm, so none is quoted here.

Why is the same trial quoted with two different percentages?

Because trials use different “estimands” — precise descriptions of the treatment effect that handle dropouts, rescue treatments, and missing data differently. STEP 1’s primary estimand assessed effects regardless of treatment discontinuation or rescue interventions ^[1]. STEP 5 used two estimands: a “treatment policy” estimand that quantifies the effect over the in-trial period regardless of discontinuation or other weight-loss interventions, and an on-treatment observation period covering only the time participants were using the trial product ^[2]. OASIS 1’s coprimary endpoints were assessed regardless of discontinuation or other bodyweight-lowering therapy, an intention-to-treat approach ^[7], and REDEFINE 1 reported effect estimates with the treatment-policy estimand, consistent with intention-to-treat ^[8].

Because estimands account for intercurrent events and missing data differently, the same trial can yield different figures depending on which estimand is applied ^[2]. When comparing numbers across trials or news stories, check which estimand is being used.

Why do real-world results often fall short of trial averages?

Trial conditions are hard to reproduce outside a study. STEP 1 participants followed a structured dose escalation to a maintenance dose, with lower doses allowed only for tolerability problems, and received counseling visits every 4 weeks plus daily diet and activity tracking ^[1]. STEP 3 went further, with 30 counseling visits and a supervised low-calorie diet phase ^[3].

Even inside that structure, adherence was not universal: by week 104 in STEP 5, about a fifth of participants were no longer on treatment ^[2]. A published real-world analysis has examined weight and glycemic changes after semaglutide or tirzepatide, broken down by whether people discontinued treatment ^[18].

What other semaglutide trials exist?

The STEP program and related trials cover other populations. One note on sourcing: the records cited for the trials below list their designs and populations only, so no weight-loss figures are quoted for any of them on this page.

• STEP 2: semaglutide 2.4 mg weekly in adults with overweight or obesity and type 2 diabetes ^[9]
• STEP UP T2D: once-weekly semaglutide 7.2 mg in adults with obesity and type 2 diabetes ^[10]
• STEP TEENS: once-weekly semaglutide in adolescents with obesity ^[11]
• STEP 6: once-weekly semaglutide in an east Asian population with overweight or obesity, with or without type 2 diabetes ^[12]
• STEP 7: semaglutide 2.4 mg weekly in a predominantly east Asian population with overweight or obesity ^[13]
• STEP 10: semaglutide 2.4 mg versus placebo in people with obesity and prediabetes ^[14]
• A trial of once-weekly semaglutide in people with obesity and knee osteoarthritis ^[15]
• SELECT: long-term weight loss effects of semaglutide in obesity without diabetes ^[16]
• SURMOUNT-5: tirzepatide compared with semaglutide for treatment of obesity ^[17]

What’s a realistic range of individual response?

The trials show a wide spread around the average. In STEP 1, 86.4% lost at least 5% of body weight, 69.1% lost at least 10%, and 50.5% lost at least 15% — which also means roughly 1 in 7 participants did not reach the 5% mark ^[1]. STEP 1 also showed greater improvement in cardiometabolic risk factors and participant-reported physical functioning with semaglutide than with placebo ^[1].

STEP 5 shows the loss can be sustained to 104 weeks on continued treatment ^[2]. STEP 1 included a 7-week period without semaglutide, placebo, or lifestyle intervention after the 68-week treatment phase ^[1].

One more thing to weigh when reading all of these numbers: STEP 1, STEP 5, OASIS 1, and REDEFINE 1 were each funded by Novo Nordisk, the drug’s manufacturer, according to the trial reports themselves ^[1][2][7][8]. The published reports for STEP 3 and STEP 8 likewise list Novo Nordisk grants, fees, and other support among the investigators’ disclosed conflicts ^[3][4]. That does not make the results wrong, but it is part of the context. Averages from these trials describe groups under study conditions, not a promise for any individual; questions about dosing and personal expectations belong with a clinician.

Sources

1. New England Journal of Medicine. Once-Weekly Semaglutide in Adults with Overweight or Obesity.
2. Nature Medicine. Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial.
3. PubMed. Effect of Subcutaneous Semaglutide vs Placebo as an Adjunct to Intensive Behavioral Therapy on Body Weight in Adults With Overweight or Obesity: The STEP 3 Randomized Clinical Trial.
4. PubMed. Effect of Weekly Subcutaneous Semaglutide vs Daily Liraglutide on Body Weight in Adults With Overweight or Obesity Without Diabetes: The STEP 8 Randomized Clinical Trial.
5. The Lancet Diabetes & Endocrinology. Once-weekly semaglutide 7.2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial.
6. PubMed. Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity.
7. PubMed. Oral semaglutide 50 mg taken once per day in adults with overweight or obesity (OASIS 1): a randomised, double-blind, placebo-controlled, phase 3 trial.
8. PubMed. Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity.
9. PubMed. Semaglutide 2.4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial.
10. PubMed. Once-weekly semaglutide 7.2 mg in adults with obesity and type 2 diabetes (STEP UP T2D): a randomised, controlled, phase 3b trial.
11. PubMed. Once-Weekly Semaglutide in Adolescents with Obesity.
12. PubMed. Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial.
13. PubMed. Efficacy and safety of once weekly semaglutide 2.4 mg for weight management in a predominantly east Asian population with overweight or obesity (STEP 7): a double-blind, multicentre, randomised controlled trial.
14. PubMed. Efficacy and safety of once-weekly semaglutide 2.4 mg versus placebo in people with obesity and prediabetes (STEP 10): a randomised, double-blind, placebo-controlled, multicentre phase 3 trial.
15. PubMed. Once-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis.
16. Nature Medicine. Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial.
17. New England Journal of Medicine. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.
18. PubMed. Changes in weight and glycemic control following obesity treatment with semaglutide or tirzepatide by discontinuation status.