Does compounded semaglutide work?
Last reviewed 2026-Aug-20 · 6 min read
Yes, people lose weight on it. The more useful question is whether it works as well as the approved product, and there the answer is: probably slightly less well, based on a single study, and nobody has run the trial that would settle it.
There has never been a randomised controlled trial comparing a compounded GLP-1 to an approved one. That sentence is the most important one on this page. Every claim you see about compounded semaglutide being "just as effective" is an assumption, not a finding.
The one comparison that exists
A digital weight loss service compared its own patients: 923 people on compounded semaglutide and 1,858 on the FDA approved product, over four months, using the same dose escalation schedule for both groups. That last detail matters, because it removes one of the obvious explanations for a difference.
What it found:
| Compounded | FDA approved | |
|---|---|---|
| Average weight loss at 4 months | 9.11% | 9.87% |
| Reached at least 10% loss | 44.6% | 50.5% |
| Reached at least 15% loss | 12.8% | 21.4% |
Read the bottom row twice. On the average, the gap is under one percentage point, which is the number most people quote. At the fifteen percent threshold, the approved group was roughly two thirds more likely to get there.
Why the gap widens at the top
The study does not explain the mechanism and neither will we. What can be said is that an average hides distribution. If compounded product varies more in potency from batch to batch, or if some patients are receiving less active drug than they think, you would expect the averages to look close and the high performers to thin out. That is a hypothesis, not a finding, and we are labelling it as one.
What about side effects?
In the same study, side effects were slightly lower in the compounded group, 71.6 percent against 77.4 percent.
That sounds like a point in favour until you read the breakdown. The difference was driven entirely by mild side effects. There was no difference in moderate or severe ones. And if a product produces both less weight loss and fewer mild side effects, one plain explanation is that some people are getting less drug.
What the review literature says
A 2026 review in the Annals of Pharmacotherapy looked at compounded semaglutide and tirzepatide products and concluded that they use unique formulations whose efficacy and safety are largely unknown. That is a formal way of saying the evidence base is close to empty.
The benchmark, for context
The approved product's own trial evidence is strong. In its main obesity trial, semaglutide at the 2.4 mg dose produced average weight loss of 14.9 percent against 2.4 percent on placebo, and 50.5 percent of participants reached at least 15 percent weight loss.
Set that next to the table above. The compounded group in the real world study reached the fifteen percent threshold at 12.8 percent. Real world results are always lower than trial results for everything, so this is not a fair head to head with the trial. It is a reminder that the numbers used to sell compounded semaglutide usually come from trials of the approved drug.
What this does not mean
It does not mean compounded semaglutide does not work. A 9.11 percent average loss over four months is a real result that most diets do not produce.
It means the evidence that it matches the approved product does not exist, the one study that looked found it slightly behind and meaningfully behind at the higher thresholds, and you should treat "just as effective" as a marketing claim rather than a fact.
What to ask
- What evidence does this provider have for their own outcomes, and is it published anywhere?
- Is my dosing schedule the same as the approved product's?
- What potency am I actually receiving per dose, and how is that verified?
- If I am not seeing results, what is the provider's process for checking the product rather than blaming the patient?
Sources
- Talay L, Vickers M. Retrospective comparison of compounded and FDA approved semaglutide in a digital weight loss service, 2024
- Compounded semaglutide and tirzepatide products use unique formulations but efficacy and safety largely unknown. Annals of Pharmacotherapy, 2026. doi:10.1177/10600280261421979
- Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine, 2021
How we verify: see /how-we-verify.
Keep reading
What the FDA has documented about compounded semaglutide safety, at /guides/is-compounded-semaglutide-safe.
How compounded semaglutide compares to Ozempic specifically, at /guides/compounded-semaglutide-vs-ozempic.