Is Your GLP-1 Weight Loss Normal? Benchmarking the Curve

Somewhere around month two or three on a GLP-1, almost everyone asks the same question: is this normal? You’ve seen someone online drop 30 pounds by now, and you’re wondering whether your slower pace means the drug isn’t working. The good news is that the pivotal trials give you a real benchmark to check yourself against. The more useful news is that the “normal” range is far wider than social media suggests.

The fastest way to see whether you’re on track is to compare your loss to a trial-based curve for your starting weight, which our GLP-1 weight loss projector builds for you. This article explains what those numbers mean.

The trial averages, in one place

Two trials anchor the benchmarks. STEP-1 studied semaglutide 2.4 mg (Wegovy) over 68 weeks; SURMOUNT-1 studied tirzepatide (Zepbound) at 5, 10, and 15 mg over 72 weeks. Both were published in the New England Journal of Medicine and both paired the drug with a reduced-calorie diet and more activity.

Drug / dose	Trial	Duration	Average total weight loss
Placebo (semaglutide trial)	STEP-1	68 wk	~2.4%
Semaglutide 2.4 mg	STEP-1	68 wk	~14.9%
Tirzepatide 5 mg	SURMOUNT-1	72 wk	~15.0%
Tirzepatide 10 mg	SURMOUNT-1	72 wk	~19.5%
Tirzepatide 15 mg	SURMOUNT-1	72 wk	~20.9%

Across the STEP-1 and SURMOUNT-1 trials, average loss worked out to very roughly 1% of starting body weight per month over the first year: front-loaded, not steady.

These are the totals at the end of each trial, roughly a year and a quarter of treatment, including the slow titration months at the start.

Average weight loss per month: a rough rule

To answer “average weight loss on Wegovy per month,” you have to convert those totals into a rate. Do it carefully, because the loss is not linear. In STEP-1, weight kept falling until about week 60 (roughly 14 months) before flattening. Spreading ~14.9% across that window gives a very rough average of about 1% of starting body weight per month over the first year.

But that average hides the shape. Loss is slow in the first month (you’re on the starting dose), picks up as you titrate to a maintenance dose, runs fastest in the middle stretch, and then tapers as you approach a plateau. So a fair way to sanity-check yourself:

• Month 1: often small; half a percent or less is common on the starting dose.
• Months 2–6: usually the fastest phase, frequently 1–2% of body weight per month for responders.
• After ~9–12 months: the pace slows as loss approaches its plateau.

Treat “1% per month” as a loose center of gravity, not a target you must hit every month. Why the curve flattens later (and why that flattening is expected physiology rather than failure) is the subject of our explainer on the GLP-1 weight-loss plateau.

Why percent beats pounds

If you’re comparing yourself to anyone else, use percent of body weight, not pounds. The trials report percent for a reason: the same drug strips more pounds off a heavier person than a lighter one, so raw pounds aren’t comparable across people. Someone starting at 260 lb losing 1% a month drops ~2.6 lb; someone at 170 lb losing the same percentage drops ~1.7 lb. Both are doing equally well by the only yardstick that generalizes.

This is why the person online who “lost 30 pounds fast” tells you almost nothing about your own progress: you don’t know their starting weight, dose, or how long it took.

The range is wide, and that’s the real point

An average is the middle of a spread. In these trials, most people cleared meaningful thresholds, but the spread around the average was large:

• In STEP-1, about 86% lost at least 5%, 69% lost at least 10%, and 51% lost at least 15%.
• In SURMOUNT-1, roughly 85–91% (depending on dose) lost at least 5%.

Flip those numbers and the honest picture appears: a real minority lost less than 5%, and some barely responded, while others far exceeded the average. Being below the average doesn’t make you abnormal: the average has half the population below it by definition. What matters more is the trend over months and whether you’re a genuine low-responder. How to tell, and what predicts a strong response in the first place, is covered in will GLP-1s work for you: predicting response.

When slow loss warrants a look

Most “is this normal?” worry is unfounded, but a few patterns are worth raising with a prescriber rather than shrugging off:

• Essentially no loss after several months at a full maintenance dose. This is the clearest signal of limited response.
• You’re still early or under-titrated. If you haven’t reached a maintenance dose, you simply haven’t tested the drug yet.
• The scale is flat but your clothes and measurements are changing. Especially if you’re strength-training, you may be losing fat while holding muscle, a win the scale hides.

The last point is why the scale alone is a poor judge. A slow scale month with a shrinking waist is not a stalled month.

The takeaway

Yes, there’s a normal, but it’s a wide band, not a single number. Averaged across the trials, GLP-1 loss runs very roughly 1% of starting body weight per month over the first year, front-loaded after the slow starting dose and flattening toward a plateau, totaling about 15% for semaglutide and 15–21% for tirzepatide by dose. Judge yourself in percent, over months, against that range, not against a stranger’s before-and-after.

To benchmark your own curve against a trial-based projection for your starting weight, use our GLP-1 weight loss projector, and for the bigger picture on what to expect throughout treatment, see our complete GLP-1 guide.

This article is educational and not medical advice. Trial averages describe groups, not individuals; whether your progress is on track is best assessed with a clinician who knows your history.

Sources

• Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med 2021 (PubMed)
• Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med 2022 (PubMed)