Semaglutide works. In the STEP 1 trial, 1,961 adults without diabetes lost 14.9% of their body weight on average over 68 weeks on a 2.4 mg weekly dose, against 2.4% on placebo [1]. The open question is the product, not the molecule. Right now, no randomized trial has tested a compounded version, and the compounded semaglutide guide explains why what's in each vial can vary.
The molecule works: what Wegovy's trials showed
Semaglutide has some of the strongest evidence of any weight-loss drug. In STEP 1, half the people on semaglutide (50.5%) lost at least 15% of their weight, compared with 4.9% on placebo, and 86.4% lost at least 5% [1]. Nausea and diarrhea were the most common side effects. The trial was funded by Novo Nordisk, which makes Wegovy.
The benefit reaches beyond the scale. SELECT enrolled 17,604 adults aged 45 or older with heart disease and overweight but no diabetes. Over a mean follow-up of 39.8 months, heart attack, stroke or cardiovascular death occurred in 6.5% on semaglutide and 8.0% on placebo, a hazard ratio of 0.80 [3]. In people with type 2 diabetes, SUSTAIN-6 found a similar cut in those events (hazard ratio 0.74), but diabetic eye complications were more common on semaglutide (hazard ratio 1.76) [4].
Every one of those results comes from Novo Nordisk's own products: Wegovy or Ozempic, made under FDA-reviewed manufacturing. That's what the evidence covers.
No randomized trial has tested compounded semaglutide
A PubMed search for compounded semaglutide, run for this update, returns 34 records. None is a randomized trial of a compounded product. Most are reviews, lab studies, market surveys and case reports.
The one outcome study is small. Researchers reviewed 94 people who received compounded semaglutide with vitamin B12 at a commercial wellness studio in 2023. After three months, they had lost 4.57% of their weight on average [5]. There was no comparison group, three months is far shorter than STEP 1's 68 weeks, and every author listed the wellness company that ran the program as an affiliation. It shows people can lose weight on a compounded product. It can't show the product matches Wegovy.
| Claim | Human evidence | Result | Strength of evidence |
|---|---|---|---|
| Semaglutide causes major weight loss | STEP 1 randomized trial, 1,961 adults, 68 weeks [1] | −14.9% vs −2.4% on placebo | Strong (brand product) |
| Compounded semaglutide works like Wegovy | No randomized trial | Not tested | Unknown |
| People lose weight on compounded semaglutide | One retrospective study, 94 people, 3 months, no control group [5] | −4.57% at 3 months | Weak |
| Compounded products match the brand's strength | None in people; one lab study by the brand's maker [6] | Differences found after light exposure | Weak; no clinical outcomes |
| Salt-form semaglutide is equivalent | None; FDA calls salts different active ingredients [8] | Not tested | No basis |
| Weight stays off after stopping | STEP 1 extension, 327 adults [2] | About two-thirds regained within a year | Strong (brand product) |
| Semaglutide lowers heart risk | SELECT randomized trial, 17,604 adults [3] | Hazard ratio 0.80 | Strong (brand 2.4 mg only) |
Strength of evidence describes the studies, not any one product. Every strong result here was measured on Novo Nordisk's approved products.
Whether your product matches depends on what's in it
A compounded vial borrows the brand's evidence only if it holds the same molecule at the strength on its label. FDA doesn't check that before a compounded drug is sold: the agency "does not review compounded drugs for safety, effectiveness or quality before they are marketed" [8].
These salt forms, including semaglutide sodium and semaglutide acetate, are different active ingredients than are used in the approved drugs. The agency does not have information on whether these salts have the same chemical and pharmacologic properties as the active ingredient in the approved drug, and we are not aware of any lawful basis for their use in compounding.[8]
Lab work points the same way, with a caveat about who did it. Scientists employed by Novo Nordisk tested compounded and follow-on samples and reported "significant disparity in strength, impurity sum, and high-molecular-weight protein level" between compounded semaglutide and the originator when the products were exposed to light [6]. The study was in vitro, it measured no patient outcomes, and its authors work for the company that sells Wegovy.
Add-ins are common too. In a 2025 secret-shopper study of 75 weight-loss clinics and medical spas in West Virginia and Oklahoma, 56.0% offered compounded GLP-1s combined with B vitamins [7]. The only weight-outcome study above used one of those combinations, so the trials behind Wegovy don't describe these products directly.
Drops, lozenges and capsules have even less behind them
Compounded semaglutide also comes as sublingual drops, lozenges and capsules. No published human trial has tested any of them, so whether they deliver a useful dose is unknown. The approved pill is a different product. Wegovy tablets contain an absorption enhancer, salcaprozate sodium. Their label says to take them on an empty stomach in the morning with no more than 4 ounces of water, then wait at least 30 minutes before eating [9]. The oral semaglutide guide covers that pill in full.
How long weight loss takes on the brand
Wegovy's label starts at 0.25 mg a week and steps the dose up every four weeks to reach maintenance [9]. STEP 1 built in 16 weeks of that escalation before participants reached 2.4 mg, and measured its main result at week 68 [2]. So the trial results describe more than a year of treatment. Early weeks on a low starting dose aren't a fair test of whether the drug works for you; that's a question for your prescriber.
Results fade when people stop
On the evidence so far, the weight loss lasts only as long as treatment does. In the STEP 1 extension, 327 participants who stopped at week 68 had lost 17.3% of their weight by then. A year later they had regained 11.6 percentage points, leaving a net loss of 5.6% [2]. Most of the heart and metabolic improvements drifted back toward baseline too. If cost could force you off treatment, plan for it now: compounded semaglutide prices are compared program by program.
What people report isn't the same as what's measured
Plenty of people say they lost weight on compounded semaglutide, and many probably did. Those reports can't tell you how much of the result came from the drug, the diet changes that come with it, or a dose that differed from the label. A trial with a placebo group and measured weights is the only way to separate them, and no compounded product has had one. Low-dose and "microdose" plans have even less data; microdosing GLP-1s covers what's known.
What this evidence can't tell you
Be clear about the gaps. The strong results above were all measured on approved brand products, in trials paid for by their maker. The single compounded outcome study was small, short, uncontrolled and run by people tied to the program. The lab findings came from scientists who work for the brand's maker and measured chemistry, not health outcomes. And FDA notes that pharmacies outside its outsourcing-facility system don't have to report adverse events, so problems with compounded products are likely underreported [8].
No study has compared a compounded product head to head with Wegovy. Until one does, the honest answer is that semaglutide works, and a compounded copy should behave like it only if it's made to the same standard. No one has measured how often a given vial meets that bar.
How to improve your odds with a compounded product
You can't test a vial at home, but you can stack the odds. Start with a program that names its compounding pharmacy, as Embody and Midi Health do on their own sites, so you can look the pharmacy up with your state board. The compounded semaglutide scores show which programs name theirs.
- Check that the label names semaglutide, not semaglutide sodium or semaglutide acetate.
- Choose a licensed prescriber who screens you before prescribing and stays reachable after delivery.
- Don't use a vial that arrives warm; FDA says heat can affect the drug's quality.
- If something seems wrong, report it to FDA's MedWatch program and tell your prescriber.
FDA advises against using any injectable GLP-1 "that arrives warm or with insufficient refrigeration, as this can affect the drug's quality" [8]. Storage rules for vials are in how long compounded semaglutide lasts in the fridge, and the wider risks are in is compounded semaglutide safe. Problems can be reported through FDA's MedWatch program [10].