If my prescription says 'with B12', is my compounded tirzepatide legal?

That is the argument some providers make. Whether a given variation produces a significant difference for the patient, rather than serving to get around the copy restriction, is judged by regulators and courts case by case. This site records what each provider says about its basis and does not decide the question.

Published August 27, 2026 · updated August 27, 2026 · regulatory and clinical facts last checked 2026-08-27 · medically reviewed by Dr. S. Shuwart, MD on August 27, 2026

Medically reviewed · August 27, 2026

Personalised compounding: what makes a compounded GLP-1 permissible after the shortage

The 'significant difference' requirement for compounding a copy of an approved drug for an individual patient, how providers use it, and what FDA has said about variations such as added vitamins or different strengths.

The rule

A 503A pharmacy may compound a drug that is essentially a copy of a commercially available approved product only if the prescriber determines that the compounded product has a change that produces a significant difference for the identified patient, and that determination is documented on the prescription. Examples FDA gives include removing an ingredient the patient is allergic to, or a different dosage form or strength the patient needs. The guidance also says that the copy restriction is not satisfied by trivial variations made to circumvent it.

How providers use it

After the shortages ended, providers and pharmacies that continued offering compounded GLP-1s generally structured prescriptions around one of these variations: a strength or dosing increment not available in the approved products, an added ingredient (vitamin B12, B6, glycine, niacinamide, L-carnitine), or a different presentation. FDA said in its 2024–2025 communications that it intended to examine whether such variations were genuine.

What to look for on a provider’s site

Whether the provider states its basis at all.
Whether the prescriber’s determination is made individually, or every patient receives the same “personalised” formulation.
Whether the additive has any clinical rationale offered, and whether that rationale claims evidence that does not exist (see the additives page).

What this site records

The Compounding Disclosure Index records, for each provider, what it says about compounded products’ approval status, its pharmacy, its formulation and its basis for compounding. We record and quote; we do not rule on legality.

Questions this page answers

If my prescription says 'with B12', is my compounded tirzepatide legal?: That is the argument some providers make. Whether a given variation produces a significant difference for the patient, rather than serving to get around the copy restriction, is judged by regulators and courts case by case. This site records what each provider says about its basis and does not decide the question.

Sources

FDA guidance: Compounded drug products that are essentially copies of a commercially available drug product under section 503A (regulator)
FDA: Clarification of policies for compounders as national GLP-1 supply begins to stabilize (regulator)

Educational information, not medical advice. Decisions about GLP-1 medication belong with you and a licensed clinician who knows your history. Compounded medications are not FDA-approved. Report an error.