Key Takeaway
A Certificate of Analysis (COA) is an independent lab report that confirms what's actually in your compounded semaglutide. Novo Nordisk testing found up to 86% impurities in some injectable compounds. Always ask for a batch-matched COA dated within 90 days of shipment, and reject any pharmacy that won't provide one.
Compounded semaglutide is a grey-market product in a white-coat package. The FDA doesn't review or approve it. Your pharmacy has one job between you and the needle: prove the vial contains what the label says. That's what a Certificate of Analysis does, and most patients have never seen one.
This guide shows you how to request a COA, what the numbers mean, and which red flags should end the conversation. Published findings from the manufacturer of Ozempic, plus case reports of life-threatening reactions, make this more than paperwork. It's the single best tool you have to avoid getting hurt by a bad batch.
What is a Certificate of Analysis?
A Certificate of Analysis is a one to three page document from an independent testing lab that confirms the identity, potency, purity, and safety of a specific batch of medication. Think of it as the lab receipt for your vial. Every reputable compounding pharmacy should produce one per batch, per USP (United States Pharmacopeia) standards.
For injectable semaglutide, a full COA covers five data points. Active ingredient identity answers whether the molecule is actually semaglutide, verified by mass spectrometry. Potency reports milligrams of active drug per milliliter. Purity lists the percentage free of impurities, byproducts, and unknown peaks. Sterility and endotoxin results confirm the product won't cause infection or a pyrogenic reaction when injected.
USP Chapter <797> governs sterile compounding in the US. A pharmacy operating to that standard already runs these tests internally. A pharmacy worth trusting also pays an outside lab to verify the results and publishes them. You want the second one.
Why COAs matter more for compounded GLP-1s
Brand-name Ozempic, Wegovy, Mounjaro, and Zepbound go through FDA-regulated manufacturing with continuous oversight. Compounded semaglutide does not. The FDA has stated repeatedly that compounded drugs don't undergo agency review for safety, effectiveness, or quality. The pharmacy is the last line of defense, and not all of them test rigorously.
In 2024, Novo Nordisk commissioned independent testing of compounded semaglutide samples purchased from US pharmacies. The results are the reason you're reading this. Some injectable samples contained up to 86% impurities. Some oral compounds hit 75% impurities. That means most of what was in the vial wasn't semaglutide at all, it was byproducts, degradation products, or unknowns the lab couldn't identify.
The FDA has received reports of life-threatening immune responses tied to compounded semaglutide, including anaphylactic shock. Several cases involved products with no batch-level testing available. If you can't see the data, you're the test subject. Our State of GLP-1 Telehealth 2026 report covers these safety signals in more detail.
How to request a COA from any pharmacy
Every pharmacy that legally compounds should be able to produce a COA within a day or two. The ask is simple. Email or call and say: "Please send the third-party Certificate of Analysis for lot number [X] matching my shipment dated [Y]."
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Start Free Assessment →If you don't know your lot number, it's printed on the vial label or the box. If you don't have the product yet, ask for a recent sample COA from the same formulation you'll be receiving. A pharmacy that can't produce either within 48 hours is a pharmacy you shouldn't be injecting.
Accredited compounders make this easier. Look for pharmacies credentialed by the National Association of Boards of Pharmacy (NABP), the Pharmacy Compounding Accreditation Board (PCAB), or the Accreditation Commission for Health Care (ACHC). These accreditations require documented quality systems and periodic inspections. They aren't a guarantee, but they're a floor. A pharmacy without any of these and without public COAs is a pharmacy with no third-party oversight at all.
Use our provider directory to filter for pharmacies that publish testing data upfront. It's faster than asking one at a time.
What to look for on a COA (red flags and green flags)
A real COA is boring. It's a grid of numbers, methods, and dates on lab letterhead. Here's what separates a document you can trust from a marketing prop.
COA reading checklist
- Independent third-party lab. The letterhead should name a lab that's not the compounding pharmacy. Eurofins, ARL Bio Pharma, and Alliance Analytical are common. If the pharmacy is testing itself, it's not independent.
- Matching batch or lot number. The lot on the COA must match the lot on your vial. A COA from "a recent batch" that doesn't match yours tells you nothing about what you injected.
- Date within 90 days of your shipment. Stability matters. A COA from 18 months ago is not evidence your current batch is clean.
- Specific numerical results. Potency should read something like "98.7% of label claim" with an acceptable range of 90 to 110%. Purity should show a percentage, not "passes" or "meets spec."
- Named test methods. HPLC (high-performance liquid chromatography) for potency and impurities. LC-MS or mass spectrometry for identity confirmation. Bacterial endotoxin test (LAL) for injectables. Sterility test per USP <71>.
- Acceptable ranges stated. Each result should list the allowed range next to the actual value. That's how you know the number means something.
Red flags are the inverse. No lab name. No lot match. No dates. Results listed only as "pass" or "conforms." No test methods. A single page with a logo and a signature and nothing else. Any of these should make you stop and ask again, or switch providers.
What the B-vitamin loophole means for purity
Here's the part most patients don't know. When the FDA declared the semaglutide shortage over in early 2025, compounding pharmacies had to stop making straight semaglutide under Section 503A's "essentially a copy" rule. You can't legally compound a copy of an approved drug that's commercially available.
Roughly 80% of compounders responded by adding something. B12. B6. NAD+. L-carnitine. Glycine. Once you add another active, it's technically not a copy anymore, and the pharmacy argues it's outside the FDA's restriction. That's the loophole. It's legally contested and the FDA has sent warning letters about it, but it's still the norm.
Why does this matter for your COA? Because every added ingredient is another chance for a contamination, a stability problem, or an immune reaction. B12 compounded with semaglutide is a different product than semaglutide alone. The COA needs to test both actives, not just one. If your "sema plus B12" COA only reports semaglutide potency, you don't actually know what's in the other half of the vial.
We cover this in detail in our compounded vs brand-name GLP-1 medications breakdown. Short version: if you're on a multi-ingredient compound, demand COAs that test every active.
Which providers publish COAs publicly?
Most compounders will send a COA only if you push. A smaller group publishes them by default, per batch, on their website. That's the gold standard.
FormBlends publishes third-party COAs on every batch, linked directly from the product page and searchable by lot number. It's one of very few telehealth platforms doing this. Eden also publishes testing data for its compounded products, which is why both show up in our rankings. A handful of direct-to-consumer pharmacies are starting to do the same, but it's still a small club.
If your current provider doesn't publish, ask. Their response tells you everything. A pharmacy that proudly sends the document is one you can trust. A pharmacy that stalls, refers you to a generic quality statement, or says "we test in-house" is one where you're flying blind. For more on what separates a real provider from a sketchy one, read how to spot a fake GLP-1 provider.
Ready to switch to a provider that publishes every batch? Start a consultation and ask to see the COA for your first shipment before it ships.
Frequently asked questions
Is a Certificate of Analysis the same as FDA approval?
No. A COA confirms that a specific batch of compounded medication matches its stated identity, potency, and purity as measured by a lab. FDA approval is a much broader regulatory process covering manufacturing, clinical trials, and post-market surveillance. Compounded semaglutide is not FDA-approved. A COA is the best third-party verification available, but it's not a substitute for agency review.
Can a pharmacy fake a COA?
Yes, which is why the lab name and lot number matter. A legitimate COA is on independent lab letterhead with contact details you can verify. If the COA is on the pharmacy's own letterhead or lists no lab at all, it's a self-report, not a third-party check. Call the lab directly if you're uncertain. Most will confirm whether a specific report is authentic.
What potency range is acceptable for compounded semaglutide?
USP standards for compounded preparations generally allow 90 to 110% of labeled potency, meaning a 2.5 mg/ml vial should test between 2.25 and 2.75 mg/ml. Anything outside that range is out of spec. Purity should be 98% or higher for a clean compound. Impurity levels above 2% are a warning sign. The Novo Nordisk findings of 86% impurities were catastrophic failures, not borderline results.
Do I need a COA for every shipment?
Ideally, yes. Each batch is technically a separate product, so a COA from three months ago doesn't certify the vial in your fridge today. At minimum, match the COA to the lot number printed on your current vial and confirm the test date is within 90 days of the fill date. Providers that publish per-batch COAs make this trivial.
What should I do if my pharmacy refuses to provide a COA?
Stop injecting that product and switch providers. A refusal to show testing data is either a legal quality program failure or an admission that the data doesn't exist. Neither is acceptable for an injectable drug. Report the refusal to your state board of pharmacy. Our directory lists providers with published testing so you don't have to guess.
Does brand-name Ozempic or Wegovy come with a COA?
Not to patients. FDA-approved drugs have batch records and quality data filed with the agency and released to pharmacies, but Novo Nordisk doesn't send a COA with each pen. You're relying on FDA oversight of the manufacturer instead. That oversight is exactly what's missing for compounded versions, which is why the COA gap matters.
How much does third-party testing add to the cost of a compound?
Roughly $100 to $400 per batch, depending on the test panel. That's a few dollars per vial spread across a production run. Pharmacies that skip testing usually do so to cut costs, not because the testing is prohibitive. If a provider tells you testing is too expensive, their margins are the issue, not the science.
Last reviewed 2026-04-16.
Medical disclaimer: This article is for educational purposes only and is not medical advice. Always consult your healthcare provider before starting any medication. Individual results vary. FormBlends is a licensed telehealth platform; nothing here replaces a personal clinical evaluation.