Compounded and unofficial GLP-1s

Cost and shortages have pushed a great many people toward compounded semaglutide and tirzepatide, and toward products sold online with no clear provenance at all. Those are two different things with different risk profiles, and both are worth understanding rather than either dismissing or recommending.

What compounding is

Compounding is the preparation of a medicine by a pharmacy for an individual patient — traditionally for legitimate reasons, such as a patient who cannot tolerate an ingredient in a commercial product, or a dose that is not manufactured.

The essential distinction is regulatory. An approved medicine has been reviewed for safety and efficacy, and its manufacturing is inspected against standards that govern purity, sterility, potency and consistency. A compounded preparation has not been through that process. It may be prepared carefully by a competent pharmacy, or it may not, and from the outside the two look identical.

Where the risks actually are

Dosing errors

This is the most frequently reported problem, and it is largely a consequence of the format. Compounded products are typically supplied as a vial and syringe rather than a pre-filled pen, and the dose must be drawn up correctly. Regulators have documented errors in which people received several times the intended dose — commonly through confusion between units and milligrams, or between the markings on different syringes.

A pre-filled pen exists precisely to remove this class of error. Removing the pen puts it back.

Unapproved forms of the active ingredient

Regulators have identified compounded products containing salt forms of semaglutide — semaglutide sodium and semaglutide acetate — which are not the same substance as the approved base and have not been shown to be safe or effective. These appeared in supply chains without being obvious to the person receiving them.

Sterility and potency

Injectable preparations must be sterile, and their strength must be what the label says. Both are guaranteed by inspected manufacturing rather than by intention. Where that oversight is absent, the person injecting has no way to verify either.

Outright counterfeits

Separate from compounding, and worse. Regulators and manufacturers have reported counterfeit pens presented as branded products, some containing the wrong substance entirely — including insulin, which in someone without diabetes can cause severe hypoglycaemia. Counterfeits have been sold through social media, unregulated websites, and occasionally through legitimate-looking channels.

Why people use them anyway

It is worth stating plainly, because pretending the reasons are frivolous helps nobody. These medicines are expensive, coverage is inconsistent, and supply has been unreliable. For many people the choice has not been between a compounded product and an approved one — it has been between a compounded product and no treatment.

That is a real dilemma and this page does not resolve it. What it can do is make sure the trade-off is understood rather than assumed away, because the marketing around these products consistently presents them as equivalent, and they are not.

Questions worth asking

If you are considering or already using a compounded product:

• Is the pharmacy licensed and verifiable in your jurisdiction? Can you check that independently rather than taking a website's word?
• What exactly is in it — the base compound, or a salt form?
• Is there a prescriber involved who has assessed you, or is this a form and a payment?
• What is the dosing instruction, in milligrams, and does the syringe supplied make that unambiguous?
• Who do you contact if something goes wrong?

If the answer to any of these is unclear, that is itself the answer.

If you are using one

Tell your regular clinician. This is the single most useful thing on this page, and it is the thing people most often avoid because they expect disapproval.

A clinician who does not know what you are taking cannot interpret your symptoms, cannot advise on interactions, and cannot help if something goes wrong. Whatever they think of the decision, they need the information — and most will focus on keeping you safe rather than on relitigating it.

The regulatory position

Rules differ substantially between countries, and they have been changing as supply has improved. In some jurisdictions large-scale compounding of these molecules has been restricted or prohibited once the approved products came off shortage lists. That means the legal position where you live may not match what a website tells you, and it may have changed since the site was written.

How this differs from a generic

The word "generic" gets used loosely in this context and it is misleading. A true generic is an approved copy of an off-patent medicine, reviewed by a regulator and required to demonstrate that it behaves equivalently to the original. It carries the same assurances.

Semaglutide and tirzepatide are not off patent in most markets, and there are no approved generics of them. A compounded preparation is not a generic — it is a pharmacy-prepared product that has not been through that review. The distinction is not pedantic; it is the entire difference in what you can rely on.

Related

• Shortages, supply and running out — This class has been intermittently unavailable since it became popular. What to do when your pharmacy cannot fill the prescription.

Which medicine you are on

Everything above applies across the class, because it comes from a shared mechanism. The numbers that differ — dose ladders, missed-dose windows, in-use storage periods, half-lives — differ by product, sometimes substantially. Each medicine has its own reference here:

Ozempic · Wegovy · Mounjaro · Zepbound · Rybelsus · Saxenda · Victoza · Trulicity · all medicines