Evidence review

Semaglutide results by month

By ·Editor·Reviewed

Quick answer

No trial publishes a figure for each month, but STEP 1 states the shape: weight loss was seen from the first check at week 4, kept going until a low point at week 60, and averaged 14.9% at week 68 (about 16 months), against 2.4% on placebo. Other trials add single points: 10.6% after 20 weeks among people who reached the full dose, 15.2% at two years, and 10.2% at four years in an older group with heart disease.

The timeline the trials state1

Every row is a number or a sentence a trial publishes, with the trial named. They are different groups of people, so the rows are points to read one at a time, not a single curve to join up.

Semaglutide weight results by time on treatment, with the trial each comes from
WhenWhat was recordedTrial
Week 4 (month 1)weight loss already seen at the first checkSTEP 1
Week 16 (month 4)2.4 mg dose reachedSTEP 1
Week 20 (about 5 months)-10.6% mean, among those who reached 2.4 mgSTEP 4
Week 60 (about 14 months)lowest point of the curveSTEP 1
Week 68 (about 16 months)-14.9% (placebo -2.4%)STEP 1
Week 104 (2 years)-15.2% (placebo -2.6%)STEP 5
Week 208 (4 years)-10.2% (placebo -1.5%)SELECT

In STEP 1’s own words, “weight loss was observed from the first postrandomization assessment (week 4) onward, reaching a nadir at week 60.” The authors add that semaglutide’s weight-loss phase lasted longer than the one reported for liraglutide in an earlier, different trial — the two drugs’ direct head-to-head is on STEP 8.

The week-20 row comes from STEP 4’s open-label run-in, and it describes the 803 people who got to 2.4 mg and went on to be randomized — not everyone who started.3 The Wegovy label says the same of that trial: people who stopped during titration were not eligible, so the results “may not reflect the experience of patients in the general population who are first starting WEGOVY® injection.”2

Why there is no month-by-month figure2

STEP 1 draws the whole curve in a figure, with a point at each visit, but does not write those points down as numbers. The Wegovy label reproduces the curve for the same trial (its Figure 7, “Study 2”) and labels only the end: at week 68, -15.6% as observed and -14.9% after filling in missing weights, against -2.8% and -2.4% on placebo.

So a chart promising a set percentage at month 2, 3 or 6 is either reading a line by eye or quoting a different study. This page leaves those months blank rather than guess, and how long semaglutide takes to work covers what the first weeks do show.

The first four months are the dose ladder2

Nobody in STEP 1 started at the full dose. It used 0.25 mg a week for the first 4 weeks and stepped up every 4 weeks to reach 2.4 mg by week 16 — the same ladder as the Wegovy label’s Table 1, which labels weeks 1 to 4 “Starting Dosage,” weeks 5 to 16 “Dosage Escalation,” and week 17 onward “Maintenance.” The label says to follow the escalation “to reduce the risk of gastrointestinal adverse reactions.” Month 1 on a starting dose is not month 1 on 2.4 mg, and the dosage chart shows each step.

Week 68: the average and the spread1

The average was -14.9% on semaglutide and -2.4% on placebo, or -15.3 kg against -2.6 kg. The trial’s second analysis, which estimates the effect if the drug was taken as intended, put it at -16.9%. The spread matters more to anyone comparing themselves with the average:

Share of STEP 1 participants reaching each threshold at week 68
Lost at least…SemaglutidePlacebo
5% of body weight86.4%31.5%
10%69.1%12.0%
15%50.5%4.9%
20%32.0%1.7%

Those shares are among the 1,212 semaglutide and 577 placebo participants weighed at week 68. Half the semaglutide group lost 15% or more; the other half did not. What the trial found for the smaller share who lost less than 5% is on not losing weight on semaglutide, and the full trial summary is on STEP 1.

Wegovy results and Ozempic results2

Everything above is Wegovy’s dose, 2.4 mg, in people without diabetes. Ozempic is the same molecule approved for type 2 diabetes, at up to 2 mg, and weight results in diabetes are smaller. Two numbers show by how much:

  • 2.4 mg in type 2 diabetes: in the label’s Study 3, weight fell 9.6% over 68 weeks against 3.4% on placebo, and 67.4% lost at least 5%.
  • 1.0 mg, an Ozempic dose: in SUSTAIN 7, weight fell 6.5 kg over 40 weeks against 3.0 kg on dulaglutide 1.5 mg.7 The trial is on SUSTAIN 7.

Dose, trial length and diabetes all differ between those figures and STEP 1’s, so they cannot be lined up as one drug doing better or worse. Ozempic vs Wegovy sets out what else separates the two labels.

After week 684

Two years. STEP 5 ran 104 weeks in 304 adults: -15.2% on semaglutide against -2.6% on placebo, with 77.1% against 34.4% losing at least 5%.

Four years. SELECT, a heart-outcomes trial in 17,604 adults with existing cardiovascular disease and no diabetes, tracked weight as well. Its analysis reports that on semaglutide “weight loss continued over 65 weeks and was sustained for up to 4 years,” at -10.2% against -1.5% by week 208.5 The smaller figure belongs to a different population, so it is not STEP 1’s curve extended. Its safety findings are on semaglutide long-term side effects.

After stopping. STEP 1 ended treatment at week 68, and an extension followed 327 of its participants for a further year off the drug. Those who had taken semaglutide had lost 17.3% by week 68 and regained 11.6 percentage points by week 120, a net loss of 5.6% — two thirds of the loss regained.6 The randomized version of the same question is STEP 4.

What this means for a compounded vial

On the label — Wegovy / Ozempic

Every timepoint above was measured on the approved product, climbed to a known dose on a fixed schedule, alongside diet and activity counseling.

In a compounded vial

No trial has tracked weight on a compounded preparation for any length of time. A vial whose strength differs from its label, or a dose measured wrongly, would move a personal timeline in ways none of these figures describe — units, milligrams and milliliters covers the measuring.

These are trial averages and shares, not a forecast for any one person, and nothing here is a suggestion to change a dose. See the medical disclaimer. Prices for the same doses are on the price index.

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Questions

What are typical semaglutide results by month?
No trial publishes a figure for each month. In STEP 1, weight loss on semaglutide 2.4 mg was seen from the first check at week 4, continued to a low point at week 60, and averaged 14.9% at week 68, against 2.4% on placebo.
What is the average weight loss on semaglutide?
In STEP 1, 14.9% of body weight over 68 weeks (15.3 kg), against 2.4% on placebo. Half the semaglutide group lost 15% or more, and 86.4% of those weighed at week 68 lost at least 5%.
How much weight do people lose in the first 4 weeks on semaglutide?
STEP 1 does not state a number for week 4. It reports that weight loss was already observed at that first check, when participants were on the 0.25 mg starting dose.
Are Ozempic results the same as Wegovy results?
No. Wegovy's 2.4 mg in people without diabetes produced 14.9% in STEP 1. In type 2 diabetes the same 2.4 mg produced 9.6% over 68 weeks, and Ozempic's 1.0 mg produced 6.5 kg over 40 weeks in SUSTAIN 7.
Does weight loss on semaglutide last?
While treatment continues, STEP 5 recorded 15.2% at two years and SELECT 10.2% at four years in an older population. After stopping, STEP 1's extension found two thirds of the loss regained within a year.

Sources

  1. Wilding JPH et al., 'Once-Weekly Semaglutide in Adults with Overweight or Obesity' (STEP 1), New England Journal of Medicine 2021;384(11):989-1002 (PMID 33567185), full text
  2. FDA prescribing information for WEGOVY (semaglutide), section 2.2 Table 1 and section 14.2 (Table 8, Figure 7), revision 6/2026 DailyMed
  3. Rubino D et al., STEP 4, JAMA 2021;325(14):1414-1425 (PMID 33755728), abstract
  4. Garvey WT et al., 'Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial', Nature Medicine 2022;28(10):2083-2091 (PMID 36216945), abstract
  5. Ryan DH et al., 'Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial', Nature Medicine 2024;30(7):2049-2057 (PMID 38740993), abstract
  6. Wilding JPH et al., 'Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension', Diabetes, Obesity and Metabolism 2022;24(8):1553-1564 (PMID 35441470), abstract
  7. Pratley RE et al., SUSTAIN 7, The Lancet Diabetes & Endocrinology 2018;6(4):275-286 (PMID 29397376), abstract