Zepbound Dosage: Every Dose, the Step-Up Schedule and Which Dose Works Best

Zepbound comes in six once-weekly strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg.1 Every presentation (single-dose pen, single-dose vial, multi-dose vial and 4-dose KwikPen) is made in all six strengths.1

The recommended maintenance doses are 5 mg, 10 mg or 15 mg once weekly for weight reduction, and 10 mg or 15 mg for obstructive sleep apnea.1

The lowest dose is 2.5 mg once weekly, used for the first 4 weeks only.1 The label states that 2.5 mg is for starting treatment and is not approved as a maintenance dose.1

After 4 weeks on 2.5 mg, the dose goes up to 5 mg, and it can then rise in 2.5 mg steps after at least 4 weeks on each dose.1 The same schedule applies to both approved uses.1

At the fastest pace, the escalation looks like this:1

• Weeks 1–4: 2.5 mg
• Weeks 5–8: 5 mg
• Weeks 9–12: 7.5 mg
• Weeks 13–16: 10 mg
• Weeks 17–20: 12.5 mg
• Week 21 onward: 15 mg

Not everyone climbs the whole ladder. The label tells prescribers to weigh response and tolerability when choosing a maintenance dose, and to consider a lower one if a dose is not tolerated.1

The dose is raised gradually to reduce the risk of gastrointestinal side effects, and because the starting dose is not meant to be a treatment dose.1 In the trials, most nausea, vomiting and diarrhea happened during dose escalation and decreased over time.1 Tirzepatide also takes about 4 weeks of weekly dosing to reach steady blood levels, which matches the 4-week step.1

In the main weight trial, average weight loss rose with dose: 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg after 72 weeks, against 3.1% on placebo.1,3 The 15 mg dose produced the largest average loss, but the step from 10 mg to 15 mg added less than the step from 5 mg to 10 mg.1

Source: Zepbound label, Study 1, intention-to-treat population.1

In a second 72-week trial in adults with type 2 diabetes, average loss was 12.8% on 10 mg and 14.7% on 15 mg, against 3.2% on placebo.1

Higher doses also brought more stomach side effects. Vomiting was reported by 8% on 5 mg, 11% on 10 mg and 13% on 15 mg, against 2% on placebo.1 Stopping treatment because of gastrointestinal effects rose from 1.9% on 5 mg to 4.3% on 15 mg.1 That trade-off is why the label leaves the maintenance dose to the prescriber. Our Zepbound side effects guide has the full table.

The highest dose of Zepbound is 15 mg injected once a week, for every approved use.1 Mounjaro, which contains the same tirzepatide, also tops out at 15 mg once weekly in adults; for children 10 and older with type 2 diabetes, its maximum is 10 mg.2

No FDA-approved tirzepatide product has a dose above 15 mg a week.1,2 See Mounjaro vs Zepbound for how the two brands differ, and what is Zepbound for the background on the drug.

It depends on the concentration of the liquid; on a standard U-100 insulin syringe, 100 units equal 1 mL.4 The FDA uses this scale in its dosing-error alert, where a 5-unit dose equals 0.05 mL.4 To turn units into mg, divide the units by 100 and multiply by the vial's concentration in mg per mL.

For brand-name Zepbound vials, Lilly's instructions are written in mL, not units. A single-dose vial holds each dose in 0.5 mL, so 2.5 mg is drawn to the 0.5 mL line, which equals 50 units.7 A multi-dose vial holds each dose in 0.6 mL (60 units), at 4.17 mg per mL for the 2.5 mg vial.1

Compounded tirzepatide is sold at many concentrations, so the same number of units can hold very different doses:

The rows are arithmetic examples, not prescriptions. With compounded semaglutide, a related drug sold the same way, the FDA has received reports of patients injecting 5 to 20 times their intended dose, with confusion between units, milliliters and milligrams among the causes.4 Always use the concentration printed on your own vial, and check the result with your pharmacist. Our dose converter does the math for any concentration.

At 10 mg/mL, 20 units (0.2 mL) is 2 mg. At 5 mg/mL it is 1 mg, and at 20 mg/mL it is 4 mg.4 Without the concentration, the question has no single answer.

There is no FDA-approved starting dose for compounded tirzepatide, because compounded drugs are not FDA-approved; the only FDA-reviewed starting dose for tirzepatide is 2.5 mg once weekly for 4 weeks.5,1 The FDA does not review compounded drugs for safety, effectiveness or quality before they are sold.5

The FDA has also seen prescriptions for compounded GLP-1s at doses beyond the approved labels, including higher doses, more frequent dosing and faster step-ups.5 On December 19, 2024, the FDA determined that the tirzepatide injection shortage was resolved, which changed the rules for pharmacies making copies.6 Our explainer on compounded tirzepatide and the comparison of compounded tirzepatide vs Zepbound cover what that means in practice.

"Microdosing" means taking tirzepatide below the label's doses, and it is not an FDA-approved way to use the drug.1 The label has no dose lower than 2.5 mg, and that dose is approved only for the first 4 weeks.1 No dosing schedule below 2.5 mg is described in the prescribing information.1

What happens if I miss a Zepbound dose? Take it within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your usual day.1 Our missed dose tool works out the timing.

Can I change my injection day? Yes, as long as at least 3 days (72 hours) separate the two doses.1

Can I go back down a dose? The label tells prescribers to consider a lower maintenance dose if a patient does not tolerate one.1 Talk to your prescriber before changing doses.

Do dose increases affect birth control pills? Yes. The label advises switching to a non-oral method, or adding a barrier method, for 4 weeks after starting and for 4 weeks after each dose increase.1

Is the Mounjaro dose schedule the same? Mounjaro also starts at 2.5 mg weekly and rises in 2.5 mg steps after at least 4 weeks, to a 15 mg adult maximum.2 Its uses differ; see Mounjaro cost for pricing.

Dose affects price as well as results. Our Zepbound cost guide shows what each strength costs, and how to get tirzepatide online compares prescribing services. If you are weighing pharmacy-made vials, see our compounded tirzepatide rankings. For alternatives, compare Wegovy vs Zepbound or browse our best GLP-1 options. Before your first dose, read how to inject Zepbound and our safety hub.

This article is for information only and is not medical advice. Never change your dose or convert units without your prescriber or pharmacist. Zepbound is a prescription drug with real risks and side effects.