Why this matters“Compounded drugs are not approved by FDA,” and since the tirzepatide shortage ended in 2024 the FDA has said it generally considers the drug commercially available.[3][5] This page compares the two on the points the FDA and the Zepbound label actually document.
Compounded tirzepatide vs Zepbound, side by side
The two differ on approval, oversight, evidence and how a dose is measured; the table sets out eight differences with their sources.
| Zepbound | Compounded tirzepatide | |
|---|---|---|
| FDA approval | Approved (weight management; sleep apnea)[1] | Not approved[3] |
| FDA review of safety, effectiveness and quality | Yes, before marketing | No: unapproved versions “do not undergo FDA's review”[4] |
| Clinical trial evidence | SURMOUNT program, e.g. 2,539 adults for 72 weeks[2] | Trials were run on the approved product, not on compounded versions |
| Who makes it | Eli Lilly | 503A pharmacies or physicians, or 503B outsourcing facilities[3] |
| Forms | Single-dose pen and vial (0.5 mL); KwikPen and multi-dose vial (4 × 0.6 mL)[1] | Varies by compounder; one FDA warning letter describes 27 mg/3 mL multi-dose vials[7] |
| Ingredients besides tirzepatide | Listed in the label: no preservative in single-dose forms; benzyl alcohol and phenol in multi-dose forms[1] | Whatever the compounder uses; not FDA-reviewed |
| How a dose is measured | Fixed volume: 0.5 mL or 0.6 mL, or a pen[1] | Depends on vial strength; FDA has reported mL/mg/units mix-ups with compounded GLP-1s[6] |
| Safety reports to FDA | Postmarketing reports summarized in the label[1] | More than 730 adverse-event reports linked to compounded tirzepatide (to May 31, 2026)[4] |
Is compounded tirzepatide the same as Zepbound?
No: it may contain the same active molecule, but it is not the same product in law or in what has been tested. Zepbound's safety, effectiveness and quality were reviewed by the FDA before it was marketed; a compounded version's are not.[4] After a shortage ends, both compounding pathways restrict making drugs that are “essentially copies” of an approved product.[3] The FDA has also warned firms that described their compounding pharmacies as “FDA approved”: its answer was that “Compounded drug products are not FDA-approved.”[8]
Does compounded tirzepatide work?
There is no FDA-reviewed evidence that it does, because the effectiveness data belong to the approved product. The weight results people quote, such as −15% to −20.9% in SURMOUNT-1, come from trials of Lilly's tirzepatide.[2] Whether a given compounded vial delivers the dose on its label depends on that compounder, which the FDA does not check before sale.[4] The FDA has also reported fraudulent compounded tirzepatide whose labels name pharmacies that do not exist.[4]
Measuring a dose: fixed volume vs variable strength
With Zepbound, every dose is one of two volumes; with compounded vials, the volume depends on the strength. A Zepbound single-dose vial is always drawn to the 0.5 mL line (50 units on a U-100 syringe), and a multi-dose vial dose to 0.6 mL (60 units).[1] A compounded 27 mg/3 mL vial, a format named in an FDA warning letter, holds 9 mg/mL, so 2.5 mg is 0.28 mL or 27.8 units.[7] The arithmetic is on compounded tirzepatide dosage, and the calculator on the home page works for any vial.
Legal status, November 2026
Compounding tirzepatide after the shortage is tightly limited. The FDA reaffirmed that the shortage was resolved on December 19, 2024, and its grace periods for compounders ended on February 18, 2025 (503A) and March 19, 2025 (503B).[5][3] The full timeline and recent warning letters are on compounded tirzepatide.
Price
Zepbound has published self-pay prices; compounded products do not have prices the FDA or Lilly publish, so we do not list them. Lilly's self-pay price for Zepbound vials or KwikPen, checked November 13, 2026, is $299 for 2.5 mg and $399 for 5 mg per 4 doses, and $449 for 7.5 to 15 mg with on-time refills.[9] Details: Zepbound vial cost.
Related
- Zepbound vial guideWhat the approved vials look like
- Compounded tirzepatide dosageStarting dose and unit math
- Zepbound side effectsThe label tables by dose
Frequently asked questions
Is compounded tirzepatide the same as Zepbound?
Does compounded tirzepatide work?
Is compounded tirzepatide legal?
Compounding pathways restrict making copies of an approved drug once a shortage ends, and the FDA's grace periods for tirzepatide ended in early 2025.[3]
Why is a compounded tirzepatide dose a different number of units?
Because compounded vials come in different strengths. Zepbound doses are fixed volumes of 0.5 or 0.6 mL.[1]
Sources
- Zepbound (tirzepatide) injection: prescribing information, Medication Guide and Instructions for Use
- Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1)
- FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize
- FDA's concerns with unapproved GLP-1 drugs used for weight loss
- Declaratory order: resolution of shortages of tirzepatide injection products (Mounjaro and Zepbound)
- FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products
- Warning letter: ProRx LLC
- Warning letter: Altru Telehealth
- Zepbound on LillyDirect: formats and self-pay prices