Ozempic vs Mounjaro Dosing Compared

Last updated: June 2026

Ozempic (semaglutide) and Mounjaro (tirzepatide) are both once-weekly type‑2‑diabetes injections, but they climb completely different dose ladders: Ozempic steps 0.25 → 0.5 → 1 → 2 mg, while Mounjaro steps 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg. They are not interchangeable milligram-for-milligram, and the number of syringe units you draw from a compounded vial depends on the vial concentration — not on which brand it is.

Have a compounded vial and a target dose? Convert any weekly dose to exact mL and U-100 syringe units in seconds.

Semaglutide calculator →

TL;DR — key takeaways

Different number lines. Ozempic tops out at 2 mg/week for type 2 diabetes; Mounjaro tops out at 15 mg/week. A 2 mg Ozempic dose is not "weak" — the molecules simply use different ranges.
Same 4-week rhythm. Both labels hold each dose for at least 4 weeks before stepping up, to let gastrointestinal side effects settle.
Branded pens meter the dose for you. You only count syringe units when you have a compounded vial of semaglutide or tirzepatide and draw it by hand.
Units follow concentration. Whether you draw 25 or 50 units depends on the mg/mL strength of the vial — the same arithmetic for either drug.
Mechanism differs. Semaglutide is a single GLP-1 receptor agonist; tirzepatide is a dual GIP/GLP-1 receptor agonist.

Why the two dose scales look so different

Semaglutide, the molecule in Ozempic, is a glucagon-like peptide-1 (GLP-1) receptor agonist. It mimics the GLP-1 hormone to trigger glucose-dependent insulin release, slow gastric emptying, and blunt appetite. Tirzepatide, the molecule in Mounjaro, is a dual agonist: it activates both the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor. Because the two drugs bind different receptor sets with different potencies, their effective milligram ranges do not line up — you cannot assume "1 mg of one equals 1 mg of the other."

Both share an elimination half-life of roughly five days, which is why each is injected once weekly and reaches steady state after about four to five weeks — the same window over which the dose is stepped up. That slow build is deliberate: the appetite and gastric-emptying effects that improve blood sugar are also what cause early nausea, so both labels start well below the maintenance dose and hold each rung for a full four weeks. In the head-to-head SURPASS-2 trial, tirzepatide produced larger HbA1c and weight reductions than semaglutide 1 mg, but that comparison used fixed doses, not the brand-by-brand ladders below.

Side-by-side: dosing at a glance

Property	Ozempic (semaglutide)	Mounjaro (tirzepatide)
Class	GLP-1 receptor agonist	GIP + GLP-1 dual agonist
Primary indication	Type 2 diabetes	Type 2 diabetes
Starting dose	0.25 mg / week (4 wks)	2.5 mg / week (4 wks)
Min step interval	4 weeks	4 weeks
Max maintenance dose	2 mg / week	15 mg / week
Titration steps	0.25, 0.5, 1, 2	2.5, 5, 7.5, 10, 12.5, 15
Route	Subcutaneous	Subcutaneous
Approx. half-life	~7 days	~5 days

Figures reflect the FDA-approved Ozempic and Mounjaro labels for type 2 diabetes. The 0.25 mg Ozempic and 2.5 mg Mounjaro starting doses are titration steps to reduce nausea, not therapeutic maintenance doses. Compounded vials are drawn manually and require you to calculate the draw volume yourself; always follow your prescriber's instructions.

The titration timeline, visualised

Both brands follow the same staircase shape — hold each rung for at least four weeks — but on different vertical scales, and Mounjaro has two extra steps at the top.

How to turn a dose into syringe units

If you inject the branded Ozempic or Mounjaro pen, the device meters each dose for you — there are no units to count. The unit math below applies when you have a compounded vial of semaglutide or tirzepatide and draw it by hand. The milligram dose on the plan is not what you read on the syringe — you read units, and a U-100 insulin syringe has 100 units per 1 mL. The conversion is always: find the concentration (mg/mL), divide your dose by it to get mL, then multiply by 100 to get units.

Worked example 1 — Ozempic / semaglutide start

A compounded vial labelled 2 mg/mL, prescribed dose 0.5 mg/week.

0.5 mg ÷ 2 mg/mL = 0.25 mL. 0.25 mL × 100 units/mL = 25 units.

Draw 25 units on a U-100 syringe.

Worked example 2 — Ozempic max dose

A vial reconstituted to 4 mg/mL, prescribed dose 2 mg/week (the Ozempic maximum).

2 mg ÷ 4 mg/mL = 0.5 mL. 0.5 mL × 100 = 50 units.

Draw 50 units — half of a 1 mL syringe.

Worked example 3 — Mounjaro / tirzepatide

A vial at 10 mg/mL, prescribed dose 5 mg/week.

5 mg ÷ 10 mg/mL = 0.5 mL. 0.5 mL × 100 = 50 units.

Draw 50 units — the same 50 units as the 2 mg Ozempic example above, despite a 2.5× larger milligram dose, because the vial is stronger.

Worked example 4 — Mounjaro at a stronger vial

The same 5 mg tirzepatide dose from a 20 mg/mL vial: 5 ÷ 20 = 0.25 mL × 100 = 25 units.

Double the concentration, half the units — for the identical milligram dose. This is why "how many units" has no single answer without the vial strength.

Worked example 5 — checking the draw fits the syringe

Mounjaro 15 mg (the maximum) from a 10 mg/mL vial: 15 ÷ 10 = 1.5 mL — more than a 1 mL syringe holds.

A 20 mg/mL vial fixes it: 15 ÷ 20 = 0.75 mL × 100 = 75 units, comfortably inside a 1 mL syringe.

Dose-to-units reference chart

Common weekly doses for each brand, shown as units on a U-100 syringe at two typical compounded concentrations. Always confirm against your own vial label.

Dose	At 4 mg/mL	At 10 mg/mL
0.25 mg (Ozempic start)	6.25 units	2.5 units
0.5 mg (Ozempic)	12.5 units	5 units
1 mg (Ozempic)	25 units	10 units
2 mg (Ozempic max)	50 units	20 units
2.5 mg (Mounjaro start)	62.5 units	25 units
5 mg (Mounjaro)	— (over 1 mL)	50 units
10 mg (Mounjaro)	— (over 1 mL)	100 units

Notice the dashes: a 5 mg or 10 mg tirzepatide dose at 4 mg/mL would need more than a standard 1 mL syringe holds, so a higher-concentration vial is used for larger Mounjaro doses. If your draw exceeds 1 mL, ask your pharmacy about a stronger vial.

How this is calculated

Every figure here uses two facts only: a U-100 syringe holds 100 units per mL, and concentration is dose-per-volume. There is no brand-specific magic constant — the arithmetic is identical for semaglutide, tirzepatide, or any other vialled peptide. The calculators on this site automate exactly this and let you sanity-check the result against the chart above. None of this is medical advice; it is the maths behind a dose your prescriber has set, and the branded pens handle the metering for you.

Frequently asked questions

Is Mounjaro just a stronger Ozempic?

No. Mounjaro's tirzepatide activates two receptors (GIP and GLP-1) while Ozempic's semaglutide activates one (GLP-1). They are different molecules on different milligram scales, so a higher number on the Mounjaro label does not mean a higher "dose" of the same thing.

Why does Ozempic stop at 2 mg but Mounjaro goes to 15 mg?

Each drug has its own potency and approved range. 2 mg is the maximum once-weekly Ozempic dose for type 2 diabetes; 15 mg is the maximum for Mounjaro. Comparing the raw numbers across brands is meaningless.

Do I draw more units for Mounjaro than Ozempic?

Not necessarily. Units depend on the vial concentration, not the brand. A 5 mg Mounjaro dose from a 10 mg/mL vial is 50 units; a 2 mg Ozempic dose from a 4 mg/mL vial is also 50 units. The stronger the vial, the fewer the units.

Can I map my Ozempic dose onto Mounjaro?

No. Switching brands is a clinical decision; your prescriber sets a new starting dose and titration plan. The 2.5 mg Mounjaro start is not equivalent to any Ozempic step — the scales do not line up.

Sources

This guide is for general educational purposes only and does not constitute medical advice. Always follow your prescriber’s specific instructions and consult a qualified clinician before changing any protocol.