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Tirzepatide Dosage Chart in Units and mg (2026): The Math That Prevents the Most Common Compounding Injury

Why units confuse everyone — and why it matters more for tirzepatide

Insulin syringes are the standard tool for drawing compounded GLP-1s, and they're marked in units because insulin has a fixed convention: U-100 insulin always contains 100 units per milliliter. The syringe borrowed that scale, so one unit is simply 0.01 mL of liquid — a volume, meaning nothing about drug content until you know what's dissolved in it. Brand Zepbound hides this behind engineered pens and fixed-dose vials. Compounded tirzepatide doesn't: each 503A pharmacy chooses its own concentration, commonly somewhere between 5 and 17 mg/mL, and prints it on the label as mg/mL (or as total mg per total mL — a 34 mg/2 mL vial is 17 mg/mL). Poison-control centers have logged GLP-1 overdose calls tied to exactly this confusion, and tirzepatide raises the stakes over semaglutide for a simple reason: the doses are bigger numbers with bigger step-ups, so an error that would be uncomfortable on semaglutide can be a multi-week ordeal on tirzepatide.

The formula, and how to use it in ten seconds

Write it on the vial box: units = (mg ÷ mg/mL) × 100. Three worked examples make it automatic. Your prescription says 2.5 mg weekly and your vial says 10 mg/mL: 2.5 ÷ 10 = 0.25 mL, × 100 = 25 units. Prescription says 7.5 mg, vial says 17 mg/mL: 7.5 ÷ 17 = 0.441 mL ≈ 44 units. Prescription says 5 mg, vial says 5 mg/mL: 5 ÷ 5 = 1 mL = 100 units — a full standard syringe, and a hint that higher doses from dilute vials may need a larger syringe or a split draw your pharmacist should walk you through. Reverse-check every draw once: units × concentration ÷ 100 should return your prescribed mg. If it doesn't, stop and call the pharmacy — thirty seconds of arithmetic against weeks of nausea.

The chart: every standard dose at the common concentrations

At 5 mg/mL: 2.5 mg = 50 units, 5 mg = 100 units, and doses above 5 mg exceed a standard 1 mL syringe — pharmacies typically move you to a stronger concentration instead. At 10 mg/mL: 2.5 mg = 25 units, 5 mg = 50 units, 7.5 mg = 75 units, 10 mg = 100 units. At 17 mg/mL (a common higher-strength preparation): 2.5 mg ≈ 15 units, 5 mg ≈ 29 units, 7.5 mg ≈ 44 units, 10 mg ≈ 59 units, 12.5 mg ≈ 74 units, 15 mg ≈ 88 units. These three columns cover most compounded tirzepatide dispensed in 2026, but they are examples, not your prescription: concentrations of 8, 12, 20 mg/mL and others exist, which is exactly why the formula beats any chart — including this one. For semaglutide users doing the same math, the identical formula applies at that molecule's smaller numbers: 0.25 mg from a 2.5 mg/mL vial is 10 units; from a 5 mg/mL vial, 5 units.

The titration schedule the units map onto

The label protocol starts everyone at 2.5 mg weekly — an initiation dose, not a treatment dose — and steps up no faster than every four weeks: 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg, holding wherever efficacy and tolerability meet. The SURMOUNT-1 dose-response explains why reaching a real maintenance dose matters: 15% average body-weight loss at 5 mg, 19.5% at 10 mg, 20.9% at 15 mg over 72 weeks. Two unit-math consequences follow. First, every titration step changes your draw — pre-calculate the whole ladder for your concentration on day one and tape it inside the medicine cabinet. Second, dose-priced programs get more expensive exactly as your units climb, which is why flat-rate structures matter; our pricing method scores that field for every provider, and the titration planner turns your ladder into calendar dates.

Switching providers: the moment errors happen

Nearly every serious units mistake we can find follows the same script: a patient switches pharmacies, the new vial is a different concentration, and they draw their old unit count. Fifty units of a 17 mg/mL preparation is 8.5 mg — drawn by someone who meant to take 2.5 mg from their old 5 mg/mL vial, that's more than triple the intended dose. The protective ritual takes one minute per new vial: find the mg/mL on the label, run the formula for your current prescribed mg, write the new unit count on the vial itself, and confirm it with the dispensing pharmacist before the first draw. Do the same after any dose change, and never inherit a unit count — not from your past self, not from a spouse on the same program, and never from a forum thread where nobody knows your concentration. If you're mid-switch between providers, our access guide covers overlapping shipments so a recalculation never happens under time pressure.

Reading the vial label like a pharmacist

Legitimate 503A labels carry the drug name and form ("tirzepatide" — base, not "tirzepatide sodium," a salt-form red flag the FDA has warned about), the concentration, a beyond-use date, storage instructions, the pharmacy's name and license state, and your name, because patient-specific dispensing is the legal basis of the whole arrangement. A vial missing the concentration is a vial you cannot dose from — full stop, call the pharmacy. A provider that can't tell you the concentration before you order is telling you it doesn't expect you to check anything else either; our safety risk map ranks that among the walk-away signals.

The semaglutide side of the chart, for households running both

Plenty of readers manage two programs under one roof — one partner on tirzepatide, one on semaglutide — and the cross-contamination risk is unit habits, not vials. The formula is identical; the numbers are an order of magnitude apart. At 2.5 mg/mL semaglutide: 0.25 mg = 10 units, 0.5 mg = 20 units, 1 mg = 40 units, 1.7 mg = 68 units, 2.4 mg = 96 units. At 5 mg/mL: 0.25 mg = 5 units, 1 mg = 20 units, 2.4 mg = 48 units. Notice the trap in both directions: a semaglutide user borrowing a tirzepatide unit count would take a massive overdose of their own drug's schedule; a tirzepatide user borrowing semaglutide numbers would under-dose into apparent non-response. House rule for dual-program homes: each vial gets its own labeled syringe stash and an index card with that person's current draw, recalculated on every new vial — never a shared mental number.

Storage, beyond-use dates, and the math that spoils quietly

Unit math delivers the right volume; storage math ensures the volume still contains the drug. Compounded tirzepatide ships and lives refrigerated at 36–46°F, and its beyond-use date (BUD) — printed on the label, typically a few weeks to a few months from compounding depending on the pharmacy's stability data — is a hard stop, not a suggestion; it is shorter than brand expiration dating because compounded sterility and stability assurances are shorter. Three quiet spoilers to audit: a shipment that arrived warm (confirm cold packs on delivery and tell the pharmacy same-day if not), a vial stored in the fridge door where temperature swings live, and freezing — a frozen peptide vial is a discarded peptide vial, no exceptions. There's also arithmetic worth doing at order time: a multi-dose vial's total mg divided by your weekly mg tells you how many weeks it covers; if that exceeds the BUD, you're paying for medicine you're scheduled to throw away, and a smaller vial or different concentration is the better order. Travel rules mirror the fridge rules — insulated case, no checked luggage, and the airline-friendly reality that syringes fly fine with the prescription label along.

Syringe technique: the three details that change your actual dose

Correct units can still deliver wrong doses through technique. Air bubbles displace medication — a bubble occupying five units means five units of drug you didn't get; draw slightly past your mark, flick the barrel upright, expel air, then settle precisely on the line, reading at the plunger's top edge at eye level. Dead space — the tiny volume left in the needle hub after the plunger bottoms out — is why "rinsing" a syringe or chasing the last drops is pointless, and why splitting one dose across two draws adds error twice; if your dose needs more than one syringe at your concentration, that's a conversation about a stronger preparation, not a workaround. And consistency beats heroics: same syringe brand, same reading technique, same site-rotation rhythm week to week makes your dosing a controlled variable, which is exactly what you want it to be when you and your clinician are interpreting results — including the plateau diagnostics in the stall guide, whose first mechanical suspect is always this page.

Practical companions: Injection technique · Loss by dose · Missed-dose rules

Frequently asked questions

Sources: Zepbound/Mounjaro FDA labeling (titration protocol); SURMOUNT-1 (NEJM 2022) dose-response; FDA communications on compounded GLP-1 dosing errors and salt forms; U-100 syringe standards; state pharmacy-board labeling requirements. Catalog: /sources/. Dosing decisions belong to you, your prescriber, and your pharmacist — this reference supports that conversation, it doesn't replace it.