Tirzepatide Dosing Guide
Weekly, stepping up 2.5 mg at a time, with 5–15 mg the maintenance zone.
Tirzepatide is the compound in Zepbound and Mounjaro. Like semaglutide, its schedule is set by the FDA label: start low, add 2.5 mg every four weeks or longer, and stop at the lowest dose that works. The doses are larger than semaglutide, which is why a 60 mg vial exists — and why the mixing math needs more care.
At a glance
- Typical dose
- Start 2.5 mg weekly; maintenance 5, 10 or 15 mg weekly (15 mg max)
- How often
- Once a week, same day each week
- Route
- Subcutaneous — abdomen, thigh or upper arm
- Timing
- Any time of day, with or without food
- How long
- Continuous; at least 4 weeks on each step
- Vial sizes
- 10 mg and 60 mg
How much
The Zepbound label starts at 2.5 mg once a week for four weeks (a starter dose, not a maintenance dose), then increases in 2.5 mg steps — 5, 7.5, 10, 12.5, 15 mg — with at least four weeks on each step. 15 mg is the maximum.
Maintenance for weight management is 5, 10 or 15 mg a week; the label treats 7.5 and 12.5 mg as transition steps. Clinic pages generally describe 5–15 mg as the landing zone, chosen by response and tolerability rather than by pushing to the top.
| Step | Dose | Notes |
|---|---|---|
| Weeks 1–4 | 2.5 mg | 4 weeks (starter dose only) |
| Weeks 5–8 | 5 mg | 4+ weeks — a maintenance option |
| Weeks 9–12 | 7.5 mg | 4+ weeks |
| Weeks 13–16 | 10 mg | 4+ weeks — a maintenance option |
| Weeks 17–20 | 12.5 mg | 4+ weeks |
| Week 21 on | 15 mg | Maximum dose |
How often & when
Once a week, any time of day, with or without food. Four weeks per step is the minimum; staying longer on a step is explicitly allowed.
Missed dose rule from the label: if 4 days (96 hours) or less have passed, take it as soon as possible; if more than 4 days have passed, skip it and resume on the usual day. The injection day can be changed as long as at least 3 days (72 hours) separate doses.
How long
Continuous, with no cycle. The trials that followed people after switching to placebo showed substantial weight regain, so sources treat tirzepatide as a schedule to maintain, not a course to finish.
Mixing the vial
Doses below are for a standard U-100 insulin syringe (100 units = 1 mL). The formula: units = dose in mg ÷ concentration in mg/mL × 100. Bacteriostatic water is the usual diluent. A standard peptide vial holds about 3 mL of liquid at most — the store’s vials included — so every row below stays at or under 3 mL. Guides elsewhere that call for 4–5 mL will not fit.
| Vial | Water added | Concentration | Doses in units |
|---|---|---|---|
| 10 mg | 1 mL | 10 mg/mL | 2.5 mg = 25 u · 5 mg = 50 u · 7.5 mg = 75 u · 10 mg = 100 u |
| 10 mg | 2 mL | 5 mg/mL | 2.5 mg = 50 u · 5 mg = 100 u (a full syringe — practical only for the 2.5 mg start) |
| 60 mg | 3 mL | 20 mg/mL | 2.5 mg = 12.5 u · 5 mg = 25 u · 7.5 mg = 37.5 u · 10 mg = 50 u · 12.5 mg = 62.5 u · 15 mg = 75 u |
A 10 mg vial is four starter doses. A 60 mg vial is 24 starter doses but only four 15 mg doses — at low doses it will outlast the ~28-day use-by window, which sources flag as waste. At 20 mg/mL a one-unit error is 0.2 mg, so read the syringe carefully.
How to reconstitute
Not sure how to mix the vial? Our free Reconstitution Calculator walks you through it: enter the vial size, how much bacteriostatic water you're adding and the amount you want per dose, pick your syringe, and it tells you exactly what mark to draw to, the concentration, and how many doses the vial holds — with a syringe diagram and a step-by-step worked example.
Practical tips
- Nausea, diarrhea, vomiting and constipation cluster around step-ups. Smaller meals, hydration and not rushing the next step are the standard mitigations.
- Rotate injection sites. Refrigerate the mixed vial and use within about 28 days.
- The label warns that tirzepatide can reduce the effectiveness of oral birth control for four weeks after starting and after each dose increase.
- Higher-concentration mixes magnify small drawing errors — double-check units before injecting.
What the evidence looks like
Evidence level
High. Tirzepatide is FDA-approved; the schedule comes from the Zepbound prescribing information, backed by the SURMOUNT and SURPASS phase 3 trials. The vial-mixing figures are community convention.
For what the compound is and how it is studied — mechanism, research history and the primary literature — read the reference entry: Tirzepatide.
Batch-tested with published COAs
Tirzepatide on the store
Every vial is tested by an independent lab, with a batch-linked certificate of analysis you can check before you buy. This page is educational; purchasing happens on the store.
Common questions
What is the starting dose of tirzepatide?
2.5 mg once a week for four weeks, then 5 mg. The label calls 2.5 mg a starter dose, not a treatment dose.
How much water do I add to a 60 mg vial?
The most-cited convention is 3 mL, giving 20 mg/mL: 5 mg is 25 units, 10 mg is 50 units, 15 mg is 75 units.
Can I stay on 5 mg?
Yes. The label lists 5, 10 and 15 mg as maintenance doses; you stop stepping up at whichever works.
Sources
The figures above were compiled from the following pages. Where an FDA label exists it is listed first; the rest are vendor, clinic and community dosing references, which are not peer-reviewed.
- Zepbound prescribing information (Lilly) — 2.5 mg start, 2.5 mg increases every ≥4 weeks, 5/10/15 mg maintenance, 15 mg max, missed-dose and day-change rules Open
- GLP3 Planner — tirzepatide reconstitution chart — 10 mg + 2 mL = 5 mg/mL; 60 mg + 3 mL = 20 mg/mL; unit tables Open