Tirzepatide vs Liraglutide Dosing Compared

Last updated: June 2026

Tirzepatide and liraglutide are both injectable incretin medicines that curb appetite, but they sit at opposite ends of the schedule: tirzepatide is injected once a week, while liraglutide is injected once every day. They also run on different milligram scales and different titration clocks, so a dose number from one tells you nothing about the other.

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

Tirzepatide calculator →

TL;DR — key takeaways

Cadence is the headline difference. Tirzepatide is one injection per week; liraglutide is seven (one each day). That is 7 vs 1 sticks across a week.
Different mg scales. Tirzepatide climbs 2.5 → 15 mg weekly; liraglutide for weight (Saxenda) climbs 0.6 → 3 mg daily. The numbers are not comparable across drugs.
Different titration clocks. Liraglutide steps up about every week; tirzepatide holds each rung at least four weeks.
Mechanism differs. Tirzepatide is a dual GIP/GLP-1 receptor agonist; liraglutide is a single GLP-1 receptor agonist.
Units follow concentration, not the drug name. The same formula converts either dose to syringe units once you know the vial's mg/mL.

Two different molecules, two different clocks

Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist with a short half-life of roughly 13 hours. That short window is exactly why it has to be taken every single day to keep a steady effect. Tirzepatide is a dual agonist — it activates both the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor — and its half-life of about five days is what lets a single weekly injection hold a stable blood level.

Because the two drugs bind different receptor sets with different potencies, their effective milligram ranges do not line up. Liraglutide's top weight-management dose is 3 mg per day; tirzepatide's top dose is 15 mg per week. Neither the per-dose number nor any weekly total is interchangeable — comparing 3 mg of one against 15 mg of the other is meaningless arithmetic.

Side-by-side: dosing at a glance

Property	Tirzepatide	Liraglutide
Class	GIP + GLP-1 dual agonist	GLP-1 receptor agonist
Injection frequency	Once weekly	Once daily
Approx. half-life	~5 days	~13 hours
Starting dose	2.5 mg / week	0.6 mg / day
Titration step interval	≥ 4 weeks	~1 week
Top weight dose	15 mg / week	3 mg / day
Titration ladder	2.5, 5, 7.5, 10, 12.5, 15	0.6, 1.2, 1.8, 2.4, 3.0
Route	Subcutaneous	Subcutaneous
Brand examples	Mounjaro, Zepbound	Victoza, Saxenda

Figures reflect the FDA-approved Zepbound/Mounjaro and Saxenda/Victoza labels. Victoza (the type-2-diabetes version of liraglutide) tops out lower, at 1.8 mg per day. Compounded vials are drawn by hand, so you calculate the draw volume yourself; always follow your prescriber's protocol.

The two titration paths, visualised

Liraglutide steps up almost weekly across its first month, climbing the 0.6 mg ladder; tirzepatide holds each rung for a full four weeks. The diagram contrasts the injection cadence and the dose ramp of each.

How to turn any dose into syringe units

The milligram dose on a protocol is not what you read on the barrel — you read units, and a U-100 insulin syringe holds 100 units per 1 mL. The conversion is identical for either drug: find the concentration (mg/mL), divide your dose by it to get mL, then multiply by 100 to get units. Brand liraglutide ships as a pre-set 6 mg/mL pen, but compounded liraglutide and all tirzepatide vials are drawn by hand, so the maths matters.

Worked example 1 — tirzepatide weekly

Vial labelled 10 mg/mL, prescribed dose 5 mg once weekly.

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

Draw 50 units once a week — half of a 1 mL syringe.

Worked example 2 — tirzepatide starting dose

Same 10 mg/mL vial, starting dose 2.5 mg weekly.

2.5 mg ÷ 10 mg/mL = 0.25 mL. 0.25 mL × 100 = 25 units.

Draw 25 units once a week.

Worked example 3 — liraglutide daily

Compounded vial at 6 mg/mL (the standard pen strength), dose 1.8 mg per day.

1.8 mg ÷ 6 mg/mL = 0.3 mL. 0.3 mL × 100 = 30 units.

Draw 30 units — every day, not once a week.

Worked example 4 — liraglutide top dose

Same 6 mg/mL vial, weight-management top dose 3.0 mg per day.

3.0 mg ÷ 6 mg/mL = 0.5 mL. 0.5 mL × 100 = 50 units.

Draw 50 units daily — the same 50 units as the weekly tirzepatide example, but seven times as often.

Worked example 5 — concentration changes the units

Liraglutide 1.8 mg from a stronger 10 mg/mL compounded vial: 1.8 ÷ 10 = 0.18 mL × 100 = 18 units.

Same dose, fewer units, because the vial is stronger. "How many units" has no answer without the mg/mL.

Dose-to-units reference chart

Common doses for each drug shown as units on a U-100 syringe at two concentrations. Confirm against your own vial label.

Dose	At 6 mg/mL	At 10 mg/mL
0.6 mg (lira start, daily)	10 units	6 units
1.2 mg (lira, daily)	20 units	12 units
1.8 mg (lira / Victoza max, daily)	30 units	18 units
3.0 mg (Saxenda max, daily)	50 units	30 units
2.5 mg (tirz start, weekly)	~42 units	25 units
5 mg (tirz, weekly)	~83 units	50 units
10 mg (tirz, weekly)	— (over 1 mL)	100 units

Note the empty cell: 10 mg from a 6 mg/mL vial needs 1.67 mL, more than a 1 mL syringe holds, so larger tirzepatide doses use a stronger vial. If a draw exceeds 1 mL, ask your pharmacy about a higher concentration.

How this is calculated

Every figure here rests on two facts: a U-100 syringe holds 100 units per mL, and concentration is dose divided by volume. There is no drug-specific constant — the arithmetic is the same for tirzepatide, liraglutide, or any other vialled peptide, which is why a single calculator handles both. The only thing that changes between these two drugs is how often you repeat the draw: once a week versus once a day. This is education and maths, not medical advice; the dose itself is set by your prescriber.

Frequently asked questions

Is tirzepatide just a stronger liraglutide?

No. Tirzepatide activates two receptors (GIP and GLP-1) while liraglutide activates one (GLP-1), and the two run on different milligram scales. A bigger number on the tirzepatide label does not mean a bigger dose of the same thing.

Why is one daily and the other weekly?

Half-life. Liraglutide clears in about 13 hours, so it needs a daily top-up; tirzepatide lasts around five days, so one weekly injection keeps a steady level.

Do I draw more units for liraglutide than tirzepatide?

It depends only on the vial concentration, not the drug. At 6 mg/mL, a 3 mg daily liraglutide dose is 50 units; at 10 mg/mL, a 5 mg weekly tirzepatide dose is also 50 units. The frequency is what differs.

Can I map my liraglutide dose onto tirzepatide?

No. Switching drugs means a fresh starting dose and titration plan set by your prescriber. The scales do not line up, so do not convert one dose into the other yourself.

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.