Patient education · Obesity, GLP-1 medication and metabolic health

Compounded Semaglutide and Tirzepatide: What to Know Before Buying Online

Compounded semaglutide and tirzepatide cost a fraction of the approved products, which is why so many people use them. The FDA has accumulated over a thousand adverse-event reports involving them, and the reasons the price is lower are largely the same as the reasons the risk is higher.

The short version

A compounded drug is not an FDA-approved drug. FDA does not review compounded products for safety, effectiveness or quality before they reach you. That is a fact about the legal category, not an allegation against any particular pharmacy.
FDA has received well over a thousand adverse-event reports involving compounded semaglutide and tirzepatide. Reporting is not mandatory for all compounders, so the true number is higher than the reported one.
The commonest serious problem is a dosing error, not a contaminated vial. Converting between milligrams, millilitres and syringe “units” has produced doses five to ten times the intended amount. Some patients required hospitalisation.
Salt forms are different active ingredients. FDA has stated that semaglutide sodium and semaglutide acetate are not the same active ingredient as the semaglutide in approved products, and they have not been shown to be safe or effective.
Counterfeits circulate widely online and may contain the wrong ingredient, too little, too much, none at all, or something harmful.
Product labelled “for research purposes” or “not for human consumption” is being sold to people to inject. That labelling exists to evade drug regulation, and such products carry no quality assurance of any kind.
The lawful route is narrowing. FDA has moved to exclude semaglutide, tirzepatide and liraglutide from the bulk substances list governing large-scale outsourcing-facility compounding.
This page does not tell you how to obtain these products. It tells you what has gone wrong, and what to do if you are already using one.

Why compounded GLP-1 products exist at all

Compounding is a legitimate and long-established part of pharmacy. A compounding pharmacy prepares a medicine for a patient who cannot use the approved product — a child who needs a liquid formulation, a patient allergic to a dye, a strength that is not manufactured. Federal law permits this in defined circumstances, including when an approved drug appears on the FDA shortage list.

The GLP-1 shortages of recent years opened that door unusually wide. Demand vastly exceeded supply, the approved products were expensive and frequently uncovered, and compounded versions appeared at a fraction of the price through telehealth platforms, medical spas, weight-loss clinics and online sellers.

Some of that activity was lawful compounding by state-licensed pharmacies working within the shortage provisions. A substantial part of it was not compounding at all. It was resale of bulk imported powder by operators with no pharmacy licence, no sterility testing and no accountability, using the vocabulary of compounding as cover.

The distinction is decisive and, from the customer’s side, nearly invisible. The same clean website, the same telehealth questionnaire, the same next-day delivery can front either. That is the central problem this page is about.

What the FDA has actually reported

Dosing errors, some requiring hospitalisation

This is the largest documented category of harm, and it is not what most people expect. They expect contamination. What has actually injured people is arithmetic.

The approved products are supplied in pens that deliver a fixed, pre-set dose. Many compounded products are supplied as a multi-dose vial and a syringe, transferring the measurement task to the patient or to a clinician who may not have handled that particular concentration before.

That measurement requires converting between milligrams, millilitres and syringe units. Concentration varies between compounders, and sometimes between batches from the same compounder, so the conversion is not stable even for an experienced user. FDA has documented incorrect calculations during exactly this step producing administered doses five to ten times the intended amount, with reported consequences including nausea, vomiting, abdominal pain, headache, dehydration, fainting and hospitalisation.

FDA has separately received reports involving patients prescribed doses beyond what the approved labelling supports — more product per dose, more frequent dosing, or escalation faster than the approved titration schedule. Faster escalation does not produce faster results; it reliably produces worse symptoms.

Salt forms are a different active ingredient

Some products sold as semaglutide are salt forms — semaglutide sodium or semaglutide acetate. FDA has stated these are different active ingredients from the semaglutide in the approved products, and that they have not been shown to be safe or effective.

This is not a technicality about nomenclature. It is a statement that what is in the vial is not the substance studied in the trials whose results are being used to sell it. It is also undetectable by inspection: the liquid looks the same.

Counterfeits and research-use-only product

FDA has warned that counterfeit GLP-1 products are widely available online and are illegal. They may contain the wrong ingredients, too little or too much active ingredient, none at all, or other harmful substances.

Enforcement has also targeted products marketed as “for research purposes” or “not for human consumption” that are in fact sold directly to people for injection. That labelling is a deliberate regulatory dodge. Its presence tells you the seller understands exactly what they are doing and has structured the sale to avoid responsibility for it.

The case where no compounding occurred

FDA has reported an adverse event associated with a product labelled as compounded tirzepatide from a pharmacy that did not compound it. The label on the vial is not evidence of who made it, where, or under what conditions.

Why the price is lower

It is worth being direct about this, because “you get what you pay for” is a slogan rather than an argument, and people who are being priced out of treatment deserve better than a slogan.

Part of the difference is legitimate. A compounded product carries none of the cost of the clinical trial programme, the regulatory submission, the post-marketing surveillance system, or the brand. Those are real costs of the approved product and a compounder genuinely does not bear them.

Part of it is not legitimate. Some sellers are not paying for pharmaceutical-grade active ingredient, sterility testing, potency assay, stability testing or cold chain. Some are not paying for a pharmacy licence, a pharmacist, or any regulatory compliance at all.

The first category is a saving. The second and third categories are simultaneously the saving and the risk — and they are indistinguishable from the outside of the transaction. That is the honest summary: you cannot tell, from the price or the website, which kind of saving you are buying.

If you are already using a compounded product

The purpose of this page is not to make anyone feel foolish. Most people using these products were behaving reasonably under real constraints: the approved drug was unaffordable, uncovered, or unavailable, and something was better than nothing.

Tell your regular clinician. Not for a lecture — because it bears on anaesthesia planning before any procedure, on your other diabetes medicines, and on anything else in the GLP-1 class. Using two GLP-1 receptor agonists at once is not appropriate, and people sometimes do it without realising.
Get your dose arithmetic confirmed in writing. If you measure from a vial, have the prescriber write down the concentration, the volume per dose and the equivalent in syringe units. Do not convert from memory, and do not rely on a number someone told you once.
Re-check at every refill. Concentration can change between batches and between suppliers. The commonest way people overdose is assuming this vial matches the last one.
Know the warning signs of dehydration. Persistent vomiting or diarrhoea that stops you keeping fluids down is a reason to contact a clinician, not to wait. Acute kidney injury has been reported with GLP-1 receptor agonists.
Report harm to FDA MedWatch. The figures quoted on this page exist only because people reported. Reporting is not an accusation; it is how the signal gets found.
Ask about the approved route again. Coverage rules, self-pay pricing tiers and manufacturer assistance categories change. What was out of reach last year may not be now.

Stopping is not dangerous in the way stopping some medicines is. But appetite generally returns and weight is commonly regained, so if you want to move to an approved product, plan the transition with a clinician rather than simply switching one injection for another.

Questions worth asking a seller before you buy

If you are going to do this anyway, these are the questions that distinguish a licensed pharmacy from an operator.

Is this a state-licensed pharmacy or a registered outsourcing facility, and under what licence number?
Is the active ingredient semaglutide base, or a salt form such as sodium or acetate?
What is the concentration, in milligrams per millilitre, and does it change between batches?
Who will confirm my dose in writing, in syringe units, for this specific concentration?
Is there a named prescriber I can contact, and is there any clinical follow-up at all?
What happens if I have an adverse reaction — who do I call?

A seller who cannot answer the first three has told you what you need to know.

The legal categories, and why they decide what you are getting

Almost every meaningful difference between one compounded vial and another comes down to which of three legal categories the maker sits in. Sellers rarely volunteer this, and it is the single most useful thing to ask about.

503A: the traditional compounding pharmacy

A 503A pharmacy compounds for an identified patient against a specific prescription. It is licensed and inspected by its state board of pharmacy. It is not required to follow the manufacturing standards that apply to drug manufacturers, and its products are not FDA-approved. This is the category most telehealth weight-loss platforms have been supplied from.

503B: the outsourcing facility

A 503B outsourcing facility registers with FDA, is subject to FDA inspection, and must follow current good manufacturing practice. It can produce in larger volumes and without a patient-specific prescription. Its products are still not FDA-approved, but the manufacturing oversight is substantially greater. The bulk substances list FDA has proposed changing is the mechanism that governs which active ingredients these facilities may use at all.

Neither: the unlicensed seller

The third category is not a compounding category. It is an operator importing bulk powder and reselling it, frequently with a “research use only” label, often from outside the United States, with no pharmacy licence, no pharmacist, no sterility testing and no adverse-event reporting obligation. Nothing in this category is lawful, and nothing in it is inspected.

A licensed pharmacy will tell you its category and its licence number without hesitation, because both are public. Reluctance to answer that question is itself the answer.

Why shortage status changed the legal picture

The permission to compound a copy of an approved drug is not open-ended. It exists largely because federal law allows compounding of a drug that appears on the FDA shortage list, on the reasoning that a patient who cannot obtain the approved medicine is better served by a compounded version than by nothing.

That is a conditional permission, and the condition is the shortage. When a shortage resolves and a drug comes off the list, the legal basis for compounding copies of it narrows sharply. This is the part of the story most people using these products never hear, because a supplier has no commercial reason to explain that its own legal footing has shifted.

The practical consequence for a patient is instability. A supply arrangement that was lawful when you started may not remain so, which means the product can disappear at short notice, the seller can change, the concentration can change with the seller, and the clinician relationship — if there was one — can evaporate. Planning a chronic treatment on that footing is a real risk quite separate from what is in the vial.

It is also why the operators in the third category above are unaffected by any of this. They were never relying on the shortage provision, or on any other provision, in the first place.

What it costs, and what insurance usually will not cover

We publish cost bands on a fixed four-tier scale rather than prices. Tier 1 is routine care. Tier 2 is a single session or short course. Tier 3 is a multi-session course or a branded medication taken indefinitely. Tier 4 is a surgical episode including facility and anaesthesia.

Band: Tier 3 — substantial. Measured per year of continuous treatment. Approved branded GLP-1 medicines sit at a sustained monthly cost in the high hundreds, taken indefinitely. Compounded products have typically been sold at a small fraction of that, which is the entire reason this market exists.

What the band excludes. Neither figure includes clinician visits, laboratory monitoring, or the cost of managing complications. In the compounded case it also excludes everything not being paid for on the manufacturing side — which is the subject of this page.

Coverage. Compounded products are generally not covered at all, which is why they are paid for in cash. Many plans cover approved GLP-1 medicines for type 2 diabetes but exclude or restrict them for weight management. Where coverage exists it usually requires prior authorisation with documented BMI and weight-related conditions; a denial must state its reason and carries appeal rights. Manufacturer assistance, patient assistance and self-pay pricing tiers exist as categories worth asking about before concluding the approved route is closed to you.

On cheaper routes. This entire page is about a cheaper route. We describe what it is and what has gone wrong with it. We do not publish sourcing instructions, seller names, or guidance on obtaining these products.

Not yet availableLifecycle: PROPOSED · reviewed monthly · last reviewed 2026-08-15

Regulatory change in progress

FDA has proposed excluding semaglutide, tirzepatide and liraglutide from the 503B outsourcing-facility bulk drug substances list — the mechanism governing which active ingredients large-scale compounders may use. If finalised, that would substantially close the lawful route for large-scale compounding of these agents, though it would not by itself stop unlicensed sellers, who were never operating inside that framework. As of this page’s review date this is a proposal, not a final rule. Proposals bind no one until they are finalised with a compliance date.