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, the cited randomized trials did not test 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
STEP 1 provides randomized evidence for the approved brand formulation. 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 3,297 people with type 2 diabetes at high cardiovascular risk, SUSTAIN-6 found a hazard ratio of 0.74 for those events over 104 weeks in a trial designed to establish noninferiority, 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.
The cited randomized trials do not establish compounded-product equivalence
The randomized trials discussed here evaluated the approved formulations. The other cited evidence includes a small uncontrolled outcome study, laboratory analysis and a two-state market survey. Those designs answer different questions; none establishes that an individual compounded product is clinically equivalent to Wegovy.
The cited compounded-product 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 documents weight loss among the participants analyzed, but cannot isolate the preparation’s effect from other care, selection or behavioral changes. 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 | Not established by the cited randomized trials | 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 | The cited maker-led laboratory study did not measure clinical outcomes [6] | Differences found after light exposure | Weak; no clinical outcomes |
| Salt-form semaglutide is equivalent | FDA does not have information establishing the same chemical and pharmacologic properties [8] | Not tested | No basis |
| Weight stays off after stopping | Exploratory STEP 1 extension, 327 adults; medication and lifestyle support stopped [2] | About two-thirds regained within a year | Limited for a sole-cause withdrawal claim; brand-specific |
| 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
The brand's trial does not establish clinical equivalence for a compounded vial, even when the ingredient name and labeled strength match. 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 compounded-product outcome study above used a semaglutide/B12 preparation, 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. The cited injection trials do not establish absorption or clinical outcomes for these non-injectable compounded formulations. Evidence for a named oral preparation would need to be assessed separately rather than inferred from injection results. 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
In the exploratory STEP 1 extension, 327 participants stopped both semaglutide and the trial’s lifestyle support at week 68, after average weight loss of 17.3%. A year later they had regained 11.6 percentage points, leaving a net loss of 5.6% [2]. Cardiometabolic measures also moved toward baseline. The subset and simultaneous withdrawal of lifestyle support limit causal interpretation; average regain does not mean everyone returned to baseline or that all benefit requires continuous treatment. 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
Personal reports can describe an experience, but cannot reliably separate the effect of the preparation from concurrent diet, other care, reporting or selection effects. A controlled study with measured outcomes helps assess those questions. The cited evidence does not supply a randomized comparison establishing equivalence to Wegovy. 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 cited 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 are not required to report adverse events to FDA, so problems with compounded products are likely underreported [8].
The cited studies do not establish head-to-head clinical equivalence between a compounded preparation and Wegovy. Matching the molecule and stated strength is insufficient: formulation, impurities, stability, delivery and clinical performance also matter. Laboratory findings from selected samples cannot estimate how often every pharmacy’s vial meets a standard or predict an individual patient’s result.
Questions to resolve before choosing a compounded preparation
You cannot establish a vial’s sterility, potency or clinical equivalence at home. Ask for the dispensing pharmacy’s identity and applicable state-board record, and use the pharmacy checklist to organize the questions. A named pharmacy is a starting point for verification, not proof that a preparation is safe or equivalent. The program comparison describes published service and financial terms rather than certifying the contents of a vial.
- 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].