Tirzepatide dosage chart: doses in mg and how units work

What tirzepatide is

Tirzepatide is a once-weekly injectable medication that acts at two receptors: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). It's FDA approved under two brand names. Zepbound is approved, alongside a reduced-calorie diet and increased physical activity, to reduce excess body weight and maintain weight reduction long term in adults with obesity, or overweight with at least one weight-related condition, and to treat moderate to severe obstructive sleep apnea in adults with obesity. Mounjaro is approved to improve blood sugar control in adults and children 10 and older with type 2 diabetes.

Belle prescribes compounded tirzepatide, prepared by a licensed compounding pharmacy for you specifically. Compounded medications are not FDA approved finished products. A licensed provider determines eligibility. Compounded tirzepatide isn't evaluated by FDA for safety or effectiveness, and it isn't equivalent to the branded products. That's why the chart below is the branded label, and your own label is the one you follow.

The tirzepatide dosage chart (FDA label)

This is the dose escalation schedule as the Zepbound and Mounjaro prescribing information states it. Both labels use the same starting dose, the same 2.5 mg steps, and the same minimum of 4 weeks before any increase.

All doses are injected under the skin once weekly, at any time of day, with or without meals, in the abdomen, thigh or back of the upper arm, rotating sites each time.

Two points are easy to miss. First, only the step from 2.5 mg to 5 mg is scheduled. Every increase after that is a choice: the Zepbound label says to consider treatment response and tolerability when selecting the maintenance dosage, and to consider a lower maintenance dosage if one isn't tolerated. Second, the label sets a minimum pace, not a target. In SURMOUNT-1, the trial behind the weight indication, the dose-escalation period ran 20 weeks before participants reached their assigned 5 mg, 10 mg or 15 mg dose.

Why the dose climbs slowly

Both labels say the escalation is there to reduce the risk of gastrointestinal adverse reactions. That matches the trial record. In SURMOUNT-1, the most common adverse events with tirzepatide were gastrointestinal, most were mild to moderate, and they occurred primarily during dose escalation.

In that trial, which studied the branded medication alongside a lifestyle program, the mean change in body weight at week 72 was -15.0% at 5 mg, -19.5% at 10 mg and -20.9% at 15 mg, compared with -3.1% on placebo. Those are group averages for Zepbound, not a forecast for any one person and not results for compounded tirzepatide. Outcomes vary by individual and are not guaranteed. A higher step isn't a better step unless it's the right one for you. Tolerability is part of the dose.

How units work

Compounded GLP-1 medications may be dispensed in multi-dose vials, and you draw each dose with an insulin syringe marked in units. Here's the part that trips people up: units measure volume, not the amount of drug. A U-100 insulin syringe holds 1 milliliter, so 100 units equals 1 mL, and FDA gives the example of a 5-unit dose being 0.05 milliliter.

Your prescription is written in milligrams. The number of units that delivers a given mg dose depends entirely on the concentration, in mg per mL, printed on your vial. The formula is:

units = mg dose ÷ concentration (mg/mL) × 100

Worked example, using a hypothetical concentration. Say a vial were labeled 10 mg/mL and the prescribed dose were 2.5 mg. 2.5 ÷ 10 = 0.25 mL, and 0.25 × 100 = 25 units.

This example is not your dose. Vials come in different concentrations, and the same mg dose takes a different number of units at each one. A vial twice as concentrated needs half the units for the same dose. That's why this guide doesn't publish a units chart: any chart is only correct for one concentration.

FDA has described dosing errors with compounded semaglutide vials, some requiring hospitalization, and said confusion between milliliters, milligrams and units may have contributed. The same math applies to tirzepatide. The fix is simple. Use the dose on your prescription label, check the concentration on your vial, and if the units and the mg on your label don't seem to match, stop and ask your care team before you inject. Belle's dosage calculator converts the dose your provider prescribed between milligrams and syringe units, so you can check the math against your label.

Branded pens work differently. Each Zepbound or Mounjaro pen is made for one dose strength, so you don't measure units at all.

Dr. Taylor on tirzepatide dosing

"I prescribe tirzepatide after a full medical intake, start at a low dose, and titrate slowly to manage the gastrointestinal side effects that are most common early on. The number that matters is the milligram dose on your label; the units are only how you measure it from your vial. If the two ever don't seem to line up, message your care team before you inject, not after."

Your label is your schedule

Compounded tirzepatide follows the dose and schedule your provider writes on your prescription label. That may differ from the branded schedule above, and your provider adjusts it based on how you tolerate each step. Belle's treatment page describes titration as personalized, started low and increased gradually. Dosing is not one-size-fits-all. Your provider sets your dose and schedule after your medical intake, and adjusts it as your treatment progresses.

What microdosing means. At Belle, microdose tirzepatide is a low, steady dose prescribed to support metabolic health as part of a longevity-focused plan, rather than to drive significant weight loss. It isn't part of the FDA label, which describes 2.5 mg as a starting dose only, and it isn't FDA approved. There's no microdose chart here on purpose: the dose is an individual prescription, set by your provider.

Missed doses, switching and restarting

The Zepbound and Mounjaro labels give the same missed-dose instruction. If a dose is missed, take it as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your regular day. Either way, resume your usual once-weekly schedule. You can change your injection day if needed, as long as doses are at least 3 days (72 hours) apart. Your own label or care team may give you different instructions for a compounded prescription, and theirs come first.

Both labels say not to combine tirzepatide with other tirzepatide-containing products or with any GLP-1 receptor agonist. If you're switching GLP-1 providers or moving between a branded pen and a compounded vial, your provider sets the dose you continue on. The labels don't give a restart schedule after a longer break, so after time off, ask your provider which dose to restart at rather than returning to your last one on your own.

Side effects and who should talk to a provider first

The most common side effects on the Zepbound label, each reported in at least 5% of patients, are nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, injection site reactions, fatigue, hypersensitivity reactions, belching, hair loss and acid reflux. Belle's safety page notes they often lessen as your body adjusts. Tell your provider if they persist or worsen.

Who should talk to a provider first

• Personal or family history of medullary thyroid carcinoma, or MEN 2
• Pregnancy, planning a pregnancy, or breastfeeding
• History of pancreatitis or gallbladder disease
• Kidney disease, or severe stomach problems such as gastroparesis
• Diabetic retinopathy
• Taking insulin or a sulfonylurea
• Taking birth control pills: 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
• A planned surgery or procedure with anesthesia or deep sedation

Where the real risk is

For most people, the largest dosing risk isn't the molecule. It's the vial with no prescriber behind it. FDA has warned about products containing tirzepatide falsely labeled "for research purposes" and sold directly to consumers with dosing instructions. It has also received adverse event reports tied to compounded doses beyond the FDA approved label: more in a single dose, more frequent doses, or faster increases.

A prescription is the answer to both. It puts a licensed provider in charge of the dose and the pace, a licensed compounding pharmacy behind the vial, and your name and concentration on the label. That's what gives the formula above something reliable to work from.

How Belle prescribes tirzepatide

Belle offers compounded tirzepatide as a once-weekly prescription. It begins with an online screening reviewed by a licensed clinician, who decides whether treatment is right for you. If you're approved, a US compounding pharmacy prepares it and ships it to you, with step-by-step guidance and nurse support for weekly at-home doses. A prescription is never guaranteed. That's the review working. For cost, see compounded tirzepatide cost and GLP-1 without insurance, and for choosing between medications, tirzepatide vs semaglutide.

On the label schedule, the first 4 weeks are at the starting dose, and escalation at the pace SURMOUNT-1 used ran 20 weeks. Weight change in that trial was measured at week 72. Timelines and outcomes vary by individual, and your provider will monitor your progress and adjust your dose as needed.

Nothing here is medical advice. Decisions about your own dose belong with a licensed provider who knows your history.

Key points

• On the FDA approved labels for Zepbound and Mounjaro, tirzepatide starts at 2.5 mg once weekly for 4 weeks, then moves to 5 mg. Any further increase is in 2.5 mg steps, after at least 4 weeks on the current dose, up to a maximum of 15 mg once weekly for adults.
• The 2.5 mg starting dose is for getting started. The Zepbound label says it isn't approved as a maintenance dosage.
• Compounded tirzepatide follows the dose and schedule your provider writes on your label, which may differ from the branded schedule.
• Syringe units measure volume, not drug. How many units a mg dose takes depends entirely on the concentration printed on your vial.
• The escalation exists for tolerability: in SURMOUNT-1, gastrointestinal side effects occurred primarily during dose escalation.

Q: Is tirzepatide FDA approved?

A: Yes, as branded products. FDA approved tirzepatide as Zepbound, for weight reduction and for moderate to severe obstructive sleep apnea in adults with obesity, and as Mounjaro, for blood sugar control in type 2 diabetes. Compounded tirzepatide is not FDA approved. It's prescribed by a licensed provider after a medical intake and prepared by a licensed compounding pharmacy for you specifically.

Q: Does Belle offer tirzepatide?

A: Yes. Belle offers compounded tirzepatide as a once-weekly prescription, available after an online screening and review by a licensed clinician. A prescription is never guaranteed.

Q: What is the starting dose of tirzepatide?

A: On the Zepbound and Mounjaro labels, 2.5 mg injected once weekly for 4 weeks. It's for getting started and isn't approved as a maintenance dosage. A compounded prescription starts at the dose your provider writes on your label.

Q: What is the maximum tirzepatide dose?

A: On the labels, 15 mg once weekly for adults. The Mounjaro label sets 10 mg once weekly as the maximum for children 10 and older with type 2 diabetes.

Q: How many units is 2.5 mg of tirzepatide?

A: It depends on your vial. Units measure volume, so the number of units equals the mg dose divided by the vial's concentration in mg per mL, times 100. The same 2.5 mg dose takes a different number of units at different concentrations. Use the dose on your prescription label, and ask your care team if the units and mg don't match.

Q: What should I do if I miss a dose?

A: The labels say to take it as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your regular day. Follow your own label or care team if they've told you something different.

Q: What is microdosing tirzepatide?

A: At Belle, microdose tirzepatide is a low, steady dose prescribed to support metabolic health rather than to drive significant weight loss. It isn't part of the FDA label and isn't FDA approved, and the dose is set individually by your provider.