Compounded Semaglutide vs Ozempic and Wegovy: What Is Actually Different

The active molecule can be identical. Almost nothing else is. An approved semaglutide product carries a formulation, a manufacturing process and a printed label that FDA reviewed before anyone injected it; a compounded vial carries none of those reviews, and FDA says so plainly.^[2] That is the comparison, and it holds even when the peptide inside both is the same peptide.

Start with what is genuinely identical

Semaglutide is a specific molecule. Both approved labels print its identity in the same terms — the same molecular formula, the same molecular weight of 4113.58 g/mol, the same peptide backbone produced by yeast fermentation.^[4][5] A compounded preparation containing semaglutide base contains that molecule. Anyone telling you the compounded version is a different drug in that narrow sense is wrong.

Hold on to the word base, because it is where the sentence stops being reliable.

A salt of semaglutide is a different ingredient

FDA has said some semaglutide sold by compounders is a salt of the molecule rather than the base. Semaglutide sodium and semaglutide acetate are, in the agency's assessment, different active ingredients from the one in the approved products. FDA adds that it holds no information on whether those salts behave the same way chemically or pharmacologically, and that it is not aware of a lawful basis for using them in compounding at all.^[1]

This is the single most consequential thing on this page, and it is invisible on a marketing site. A page saying “semaglutide” is not telling you which form is in the vial. The label and the pharmacy can. Where a seller in our register will not name the pharmacy that compounded its product, we record that as a finding rather than an omission — see the pharmacy register.

Ozempic and Wegovy are one molecule with two labels

Most readers comparing compounded semaglutide to Ozempic have a second misconception underneath the first: that Ozempic and Wegovy are different drugs. They are the same molecule. What differs is what each was approved to treat and how high its dosing is allowed to go.

So “compounded semaglutide vs Ozempic” and “compounded semaglutide vs Wegovy” are not two questions about chemistry. They are one question about chemistry and two questions about which reviewed label you are stepping outside of.

A compounded vial has no approved label, so it has no reviewed dose ladder

The escalation schedule on an approved label is not a suggestion someone wrote down. It is part of what was reviewed. Both semaglutide labels open at 0.25 mg weekly for four weeks and step up on a fixed cadence, and the Ozempic label states its own maximum in a sentence.^[4][5] A compounded product has no such document behind it, because FDA does not evaluate a compounded drug's safety, effectiveness or quality before it reaches a patient.^[2]

The consequence shows up in FDA's own mailbag. The agency reports adverse events from patients prescribed compounded semaglutide or tirzepatide at doses beyond what the approved labeling describes: more product in a single dose, doses taken more often, or the amount increased faster than the approved titration.^[1] None of those three is a manufacturing failure. Each is a decision that an approved label would have constrained and a compounded preparation does not.

A concentration is not a dose

Approved presentations hand you a dose. The Ozempic cartons say the pen delivers doses in fixed increments and nothing else; the multi-dose Wegovy pen holds 9.6 mg in 3 mL and delivers four 2.4 mg doses.^[4][5] Even where a concentration appears, the device meters the amount for you.

A compounded multi-dose vial is sold as a concentration, in milligrams per milliliter, and the dose is arithmetic that someone has to do correctly with a syringe. Three cases that reached a regional poison center show what that costs when it goes wrong: two patients self-administered 10-fold overdoses, one was dosing in milliliters and units rather than milligrams, and one had been handed a vial and syringes with no counseling on how to use them. The authors' conclusion was that these vials lack the safety features built into prefilled manufactured pens.^[6] Three cases is three cases, not a rate. It is also the exact mechanism FDA describes when it reports dosing-error adverse events, some requiring hospitalization, from patients measuring and self-administering incorrect amounts.^[1]

Extra ingredients make it a different preparation

Compounded vials sometimes list a second active ingredient beside the semaglutide, cyanocobalamin among them. No approved semaglutide injection contains a vitamin of any kind — not the Ozempic presentations, and not the Wegovy ones.^[4][5] What the Ozempic label lists alongside the drug is unglamorous and short: disodium phosphate dihydrate, propylene glycol, phenol and water for injections in the pen presentation, and a different set again — disodium phosphate dihydrate, sodium chloride and water for injection — in the single-dose syringe.^[4]

That second list is worth a moment. Two presentations of the same approved drug carry different excipients, each reviewed for the presentation it belongs to. It is a small illustration of what approval covers: not the molecule in the abstract, but this formulation, in this container, at this strength. We take the B12 question apart separately in why compounded semaglutide is mixed with B12.

The safety record you can look up is not the same size

FDA has received 990 adverse-event reports involving compounded semaglutide and more than 730 involving compounded tirzepatide, counted as of May 31, 2026. The agency notes that many of them look consistent with events already known for the approved versions. It also notes the reason those numbers understate the picture: federal law does not require a state-licensed pharmacy that is not an outsourcing facility to submit adverse events to FDA at all, so reports from compounded products are likely undercounted.^[1]

Outsourcing facilities sit under different obligations. Registered under section 503B, they are subject to current good manufacturing practice requirements, are inspected by FDA on a risk-based schedule, and do have to report adverse events.^[2] Two vials of compounded semaglutide can therefore come with meaningfully different amounts of public evidence behind them, and neither carries as much as an approved product.

Where the legal position now stands

The comparison used to have a third element: availability. Compounded semaglutide was widely lawful to sell because the drug was in shortage. That determination flipped on February 21, 2025. FDA then let its enforcement discretion run to April 22, 2025 for state-licensed pharmacies and to May 22, 2025 for outsourcing facilities.^[3] In its April 1, 2026 update the agency recorded that neither molecule sits on the 503B bulks list, and that neither is in shortage.^[3]

Compounding for an individual patient with a documented need did not end, and our breakdown of which GLP-1s can still be compounded sets out what that requires. If a program you are already on has stopped, what to do next covers the routes that remain.

Five questions that separate the two products

1. Is this semaglutide base, or a salt? Ask for the form by name. FDA says it knows of no lawful basis for compounding with semaglutide sodium or semaglutide acetate.^[1]
2. Which pharmacy compounded it, and under 503A or 503B? The answer changes the manufacturing standard, the inspection schedule and whether adverse events reach FDA at all.^[2]
3. What is the concentration, and how many units is my dose? Ask in the units printed on the syringe you were sent, not in milligrams alone.^[6]
4. What else is in the vial? A second active ingredient makes it a different preparation from anything approved.^[4]
5. What happens to the price when the dose goes up? Where a program prices by strength, the figure climbs with the ladder, and the ladder climbs by design. We track what sellers charge on the live price tracker and rank the compounded market on /best/compounded-semaglutide.

One answer is disqualifying on its own. FDA's list of telehealth warning signs opens with a company that claims its compounded drug is the same as an FDA-approved drug.^[1] A seller willing to say that has told you how carefully it reads the rest.