There is no approved starting dose for compounded tirzepatide, because there is no FDA-approved compounded tirzepatide. A dose is only “approved” relative to a specific product that a regulator reviewed, and no compounded vial has been through that review. This page will not publish a compounded dosing schedule.
What can be published, because it is printed on an FDA label, is the starting dose of the approved products: 2.5 mg injected subcutaneously once weekly, for both Mounjaro and Zepbound. Those two facts are not the same answer, and the rest of this page is about why.
What the approved labels start at
Zepbound’s label is the more explicit of the two: the recommended starting dosage for all indications is 2.5 mg injected subcutaneously once weekly for 4 weeks, and the 2.5 mg dosage is for treatment initiation and is not approved as a maintenance dosage. The escalation exists, in the label’s words, to reduce the risk of gastrointestinal adverse reactions — not to search for an effective dose.
Zepbound, all indications. Maintenance is 5, 10 or 15 mg for weight reduction and 10 or 15 mg for obstructive sleep apnea; the maximum is 15 mg weekly. Mounjaro uses the same 2.5 mg start and the same 2.5 mg increments at intervals of at least 4 weeks, to a maximum of 15 mg weekly in adults and 10 mg in paediatric patients.
One correction worth making, because it is quoted everywhere: the sentence that 2.5 mg is not intended for glycemic control is not in the current Mounjaro label. What that label now says is to increase in 2.5 mg increments after at least 4 weeks on the current dose if additional glycemic control is needed. The equivalent restriction survives on Zepbound, which states that 2.5 mg is not approved as a maintenance dosage.
Why none of that is a dose for a compounded vial
A label dose is a statement about one specific manufactured product. It assumes a verified strength, a known formulation and, in Zepbound’s case, a device calibrated to deliver it — the label lists exact strengths per presentation, down to 10 mg/2.4 mL for a pen that delivers 2.5 mg four times.
A compounded vial carries none of those guarantees. The FDA’s position is blunt: compounded drugs are not FDA approved, which means the agency does not review them for safety, effectiveness or quality before they are marketed. Transplanting “2.5 mg” from a Zepbound label onto a vial of unknown concentration is not following a label; it is guessing with a number borrowed from one.
The consequences are being counted. As of 31 May 2026 the FDA had received more than 730 adverse event reports for compounded tirzepatide, alongside 990 for compounded semaglutide, and has said the semaglutide reports include adverse events — some requiring hospitalisation — that may be related to dosing errors.
The shortage that made this legal ended in December 2024
Compounding a copy of an approved drug is normally restricted. The exception that opened the door for tirzepatide was its presence on the FDA drug shortage list, and that door is shut. The sequence, from the FDA’s own declaratory order:
- 15 December 2022 — tirzepatide injection products added to the FDA drug shortage list.
- 2 October 2024 — FDA determines the shortage resolved and removes them from the list.
- October 2024 — that decision is challenged in court and remanded to the agency for reevaluation.
- 19 December 2024 — FDA reissues it as a declaratory order that revokes and replaces the October decision, stating that the tirzepatide injection product shortage is resolved.
- 18 February 2025 — end of the 60-day period during which FDA did not intend to take action against state-licensed pharmacists and physicians compounding under section 503A.
- 19 March 2025 — end of the 90-day equivalent for outsourcing facilities under section 503B.
Both dates are long past. Semaglutide followed the same path: the FDA determined its injection shortage resolved on 21 February 2025, with 503A compounding to stop by 22 April 2025 and 503B by 22 May 2025.
There is also a trapdoor for the workarounds. The FDA has said it may consider a compounded product that combines a GLP-1 active ingredient with another one — semaglutide with vitamin B12 is the example it gives — to be essentially a copy of a commercially available drug product, which is the thing the rules restrict.
What this site will not publish
Two rules apply here, and they are the same rules used on every unapproved compound on this site.
- No dosing schedule without an approval behind it. A compounded tirzepatide product has no label, no approved indication and no approved dose, so none is published — not as a “typical” schedule, not as a “common protocol”, not as a starting point.
- No animal dose converted into a human one. Milligrams per kilogram from a rodent study are not a human dose and are never presented as one.
The 2.5 mg figure above is publishable only because tirzepatide itself is approved and the number is printed on an FDA label. It describes Mounjaro and Zepbound. It does not describe anything else.
Related
- Tirzepatide dosage calculator and the full approved titration schedule
- Is there a semaglutide to tirzepatide conversion? — no, and the pharmacology explains why.
- Why compounded semaglutide is not a generic — the same regulatory distinction, applied to the other molecule.
- How long tirzepatide stays in your system