Tirzepatide Dosage Chart: The Titration Ladder the FDA Label Actually Specifies

Most tirzepatide dosage charts online are correct and useless at the same time. Correct, because the ladder is on an FDA label and nobody has to guess at it. Useless, because the reader searching for it is usually holding a compounded vial with a concentration printed on it in mg/mL, and no chart of milligram-per-week numbers tells them how those two things relate.

This page does both halves: the label's ladder, quoted from the label, and the arithmetic that maps a vial's concentration onto it. Neither half is dosing advice — the number you take comes from a prescriber, and the label's own escalation instructions are written for a prescriber, not for the person holding the syringe.

The one-paragraph answer, including for compounded vials

The FDA-approved starting dose of tirzepatide is 2.5 mg injected subcutaneously once weekly, for four weeks. Both approved labels are explicit that this is an on-ramp and not a treatment dose: Zepbound's states "the 2.5 mg dosage is for treatment initiation and is not approved as a maintenance dosage," and Mounjaro's states it "is for treatment initiation and is not intended for glycemic control¹²." After four weeks the dose increases to 5 mg once weekly, and from there in 2.5 mg increments after at least four weeks on the current dose¹.

There is no separate approved starting dose for a compounded product, because compounded products are not FDA-approved and carry no FDA-reviewed label of their own. A compounded tirzepatide prescription is written by a prescriber, and the label ladder above is the reference point that prescriber is working from — not a rule the compounded vial itself carries. FDA has reported adverse events, some requiring hospitalization, from patients "prescribed compounded semaglutide or tirzepatide products in doses beyond what is in the FDA-approved drug label," including "using more product in a single dose, taking doses more frequently or increasing the amount more quickly (titration schedule)⁵."

The ladder, and why every step is four weeks

The escalation interval is not arbitrary and the label says why: follow the schedule "to reduce the risk of gastrointestinal adverse reactions¹." That is the entire purpose of the ramp. Nausea, vomiting, diarrhea and constipation are the dominant adverse events in every tirzepatide trial, they are dose-related, and they cluster during escalation — SURMOUNT-1's own report notes the most common adverse events were gastrointestinal, mostly mild to moderate, "occurring primarily during dose escalation³."

The maintenance dose is not a single number. Zepbound's approved maintenance doses for weight reduction and long-term maintenance are 5 mg, 10 mg or 15 mg once weekly; for obstructive sleep apnea, 10 mg or 15 mg; the maximum for all indications is 15 mg¹. Mounjaro's maximum is 15 mg once weekly in adults and 10 mg once weekly in pediatric patients aged 10 and older². Zepbound's label adds an instruction that most charts omit entirely: "Consider treatment response and tolerability when selecting the maintenance dosage. If patients do not tolerate a maintenance dosage, consider a lower maintenance dosage¹." The ladder is explicitly two-way.

Worth noting what the trials did rather than what a chart implies. SURMOUNT-1 randomized 2,539 adults to 5, 10 or 15 mg weekly over 72 weeks — "including a 20-week dose-escalation period³," which is the label's four-week steps run all the way from 2.5 mg to 15 mg with none skipped. SURPASS-2 tested the same three maintenance doses against semaglutide 1 mg in 1,879 adults with type 2 diabetes over 40 weeks⁴. Nobody in those trials started at a maintenance dose.

Missed doses, and changing your injection day

The label is unusually specific here, and the numbers differ from semaglutide's — a real trap for anyone switching molecules.

If a tirzepatide dose is missed, it can be administered as soon as possible within 4 days (96 hours) of the missed dose. If more than four days have passed, the missed dose is skipped and the next one taken on the regularly scheduled day, resuming the normal weekly rhythm¹². The day of weekly administration can be changed if necessary, as long as at least 3 days (72 hours) separate the two doses¹.

For contrast, and this is exactly the kind of detail that gets muddled: Ozempic's window is five days, and Wegovy's rule is framed differently again — administer if the next scheduled dose is more than two days away, skip if it is less. Our companion page on the semaglutide labels covers those, including the rule about restarting escalation after two consecutive missed doses, which tirzepatide's label has no equivalent of.

The part no chart covers: mg per week versus mg per mL

Here is the thing the approved product hides and a compounded vial cannot.

Zepbound and Mounjaro's multi-dose vials and pens come in six strengths, and Lilly matched the concentration to the dose so the injected volume never changes. Every one of them delivers 0.6 mL: 2.5 mg comes from a 4.17 mg/mL vial, 5 mg from 8.33 mg/mL, 7.5 mg from 12.5 mg/mL, 10 mg from 16.7 mg/mL, 12.5 mg from 20.8 mg/mL, and 15 mg from 25 mg/mL¹. The single-dose pens and vials do the same thing at 0.5 mL, from 2.5 mg/0.5 mL up to 15 mg/0.5 mL¹. Move up the ladder on the approved product and the volume in the syringe is identical every week; only the box changes.

A compounded vial does the opposite. It has one concentration for the life of the vial, so every step up the ladder is a bigger volume. The arithmetic is simple and it is worth writing out precisely because it is where mistakes happen:

• •Volume (mL) = dose (mg) ÷ concentration (mg/mL).
• •On a U-100 insulin syringe, 1 mL is marked as 100 units — a property of that syringe, not of the drug. So units = mL × 100.

Run it on the label's own numbers to see the pattern rather than on a hypothetical. At 25 mg/mL — the concentration Zepbound uses for its 15 mg dose — a 15 mg dose is 15 ÷ 25 = 0.6 mL, or 60 units on a U-100 syringe. At that same 25 mg/mL concentration, a 2.5 mg dose would be 2.5 ÷ 25 = 0.1 mL, or 10 units. Same vial, same syringe, a sixfold difference in what you draw. That is why "how many units of tirzepatide" has no answer without the concentration in front of you, and why a units figure copied from a forum post is not transferable between vials.

⚠ Two things this arithmetic does not do. It does not tell you what your dose should be — that is your prescriber's. And it does not verify what is in the vial: the concentration used in the calculation is whatever the label on that vial claims, and compounded products are not FDA-reviewed for identity, strength or purity before sale. Our reconstitution calculator runs this arithmetic on numbers you enter, and our units-to-mg converter runs it in the other direction.

Why the label matters more, not less, for a compounded prescription

The legal basis on which compounded tirzepatide was sold at scale has narrowed considerably since 2024 — our timeline of FDA's own dates covers it step by step — and one of the narrow paths that remains is a prescriber documenting that a specific patient needs a dose or formulation the commercial product does not offer⁶. That is worth understanding for a reason that has nothing to do with law: it means a compounded dose that sits off the label's ladder is, by design, an individualized clinical decision about you, not a standard protocol. It should have a reason attached to it that someone can state.

If you are comparing where to get it, the practical variables are the pharmacy, the stated regulatory category, and the real standing price. Our tirzepatide provider comparison reads each of those off the companies' own pages, our cost view sorts the same roster by true monthly price, and our explainer on what compounded tirzepatide actually is covers how a compounded vial differs from the approved product in oversight and dose form.

The bottom line

The FDA-approved tirzepatide ladder is 2.5 mg for four weeks, then 5 mg, then 2.5 mg increments no faster than every four weeks, to a maintenance dose of 5, 10 or 15 mg and a hard ceiling of 15 mg once weekly. Missed doses can be taken within four days; the injection day can move with at least 72 hours between doses. Every one of those numbers is on a label, which is why this page can state them without hedging. What no label can tell you is what a particular compounded vial contains or what dose is right for you — the first is a question for the pharmacy that made it, and the second is a question for the prescriber who wrote it.