Page last checked 2026-07-22

How-to · injection guide

How to inject Tirzepatide

Tirzepatide goes under the skin, not into muscle, once a week. You use the abdomen, thigh or upper arm, moving to a different spot each time, and you pick a day of the week and keep to it.

You can shift the day if you need to, as long as two doses stay at least 72 hours apart. The injection itself is taught by the prescriber or pharmacist who dispenses it, and everything below is what the label says.

What matters first

Where it goes: Under the skin of the abdomen, thigh or upper arm
How often: Once each week, on the same day
If the day changes: Keep at least 72 hours between doses

Sold as Zepbound and Mounjaro — the same molecule in every presentation, so the route is the same too.

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewerReviewed 2026-07-22open the primary sources

Where does tirzepatide go?

Under the skin of the stomach, the thigh and the back of the upper arm. Stay at least 2 inches from the belly button. The label describes the back of the upper arm as an injection another person gives.

A front and a back body outline. They mark where Tirzepatide goes under the skin: the stomach, the thigh and the back of the upper arm. The area around the navel is hatched out. The label says to stay at least 2 inches from the belly button. The label describes the back of the upper arm as an injection another person gives. Open circles inside each area are the spots to move between. One filled circle is this dose. The label says to use a different spot for every dose. The same area of the body can be used again, the same spot cannot. Never into muscle or a vein. And not skin that is tender, bruised, scaly or hard, skin with pits, lumps or thickening, or scars and damaged skin. — Front and back, with the label’s own sites marked. The circles inside each area are the point of the drawing: they are spots to move between, not spots to hit.

Rotation: A different spot for every dose — the same area of the body can be used again, the same spot cannot.
Never into: Muscle or a vein. Not skin that is tender, bruised, scaly or hard, skin with pits, lumps or thickening, or scars and damaged skin.

FDA labelSource: Zepbound (tirzepatide) — FDA-approved Prescribing Information · retrieved 2026-07-22

What does the label actually say?

Route. Subcutaneous only — the fat layer just under the skin, never a muscle or a vein.
Timing. Once a week, same day, food or no food. The day can move as long as two doses stay 72 hours apart.
Sharing. Pens and needles are never shared, even with a fresh needle.

FDA labelSource: Zepbound (tirzepatide) — FDA-approved Prescribing Information · retrieved 2026-07-22

How many units is each label dose?

A branded pen measures the dose for you. A vial does not — you draw it by volume, and every step of the schedule becomes a different number of units on the syringe. The table holds the water volume fixed so the steps line up side by side.

◆ Label doses at 10 mg in 2 mLU-100 syringe

Step	Label dose	Volume	Draw to
1	2.5 mg	0.50 mL	50.0 units
2	5 mg	1.00 mL	100.0 units
3	7.5 mg	1.50 mL	150.0 unitsexceeds syringe
4	10 mg	2.00 mL	200.0 unitsexceeds syringe
5	12.5 mg	2.50 mL	250.0 unitsexceeds syringe
6	15 mg	3.00 mL	300.0 unitsexceeds syringe

Straight arithmetic for a 10 mg vial in 2 mL, where 1 U-100 unit = 0.01 mL. The doses come from the label; the unit column is the math at this concentration, not a recommendation.

Compute this for your own vial and water →

What this schedule asks of you that the others do not

The schedule behind this page is the longest on the site. It is also the only one that can be stopped at three separate places and still be finished. And this page, unlike its neighbor, states in plain terms what to do about a dose you missed.

Where can this schedule stop?

Three of its six steps are marked as places to stay. That is unusual. Most schedules climb to one destination. This one offers a low, a middle and a top. Each is a finished course rather than a stage on the way to another.

It matters here because every step is a different number of marks on the barrel. Somebody who stops at the low step draws a third of what somebody at the top draws. Same glass, same water, a third of the volume. The table on this page is the only place the two are set side by side.

What if you miss a dose?

The source gives a specific rule, so the guide uses that rule instead of borrowing general advice from another compound.

The rule has two halves and both are easy to lose. There is a window inside which the missed dose is still taken. There is also a minimum gap between any two doses, and the window may not break it.

Why does the top step take so long to reach?

The highest place to stay is six times the amount of the first step, and every timed step in between lasts four weeks. Multiply that out and the top of this schedule is months away from the bottom by design.

The length is the point rather than a delay. Each step is a stretch of time at one amount before the next arrives. Compressing it does not get anybody there sooner. It moves the same increase into a week the body has not settled into.

Does the vial or the pen change any of this?

The route and the sites do not change. What changes is who does the measuring. A pen is built around the schedule and hands out a step; a vial hands out a volume and leaves the step to arithmetic.

Five vial sizes are documented. The same dose can therefore produce five different syringe-unit readings, depending on the vial strength and water added.

Why does the label send the upper arm to somebody else?

The Instructions for Use say another person should give an injection in the back of the upper arm. The abdomen and thigh are listed for self-injection.

The label gives the distance from the navel in inches only. No metric conversion is added because the label does not provide one.

Why does the site have to move?

Using the same spot over and over hardens the tissue underneath, and hardened tissue absorbs differently. Since absorption decides how much of a dose actually reaches you, moving the site is about consistency as much as comfort. The label directs rotation between doses, and against injecting skin that is already tender, bruised, red or hardened.

Private rotation log

Keep track of where you injected

stays on this device

Save the date, body area and a short note about the spot. This log records your choice; it does not choose an injection site for you.

Injection date

Body area

Note about the exact spot (optional)

Where does the needle go afterwards?

Used needles belong in an FDA-cleared sharps container, or failing that a heavy-duty plastic container with a tight lid — never loose in household trash or recycling. What happens to a full container is set locally rather than federally, so collection varies by state and city.

Boxed warning

Risk of thyroid C-cell tumors

Tirzepatide caused thyroid C-cell tumors in rodents. It is not known if this happens in people. The label rules it out for anyone with a personal or family history of MTC or MEN 2.

Questions people ask about injecting tirzepatide

Where is tirzepatide injected?

Under the skin of the abdomen, thigh or upper arm, moving spot between doses. The label does not describe injecting into muscle or a vein.

Does the injection site change how well it works?

The label lists the three sites without ranking them, so it comes down to comfort and rotation. What it does direct against is tissue hardened by repeated use, because absorption from damaged tissue is less predictable.

Can the injection day be changed?

Yes, as long as two doses stay at least 72 hours apart.

What happens if a dose is missed?

Missed dose: take within 4 days (96 h), otherwise skip; keep doses ≥ 72 h apart

Does the injection hurt?

The needles are short and fine, and most people describe barely feeling it. Some redness or soreness at the spot is expected rather than unusual — reactions where you inject are listed as common on the label.

Is the technique the same for a vial as for a pen?

The route and the sites are the same, but a pen measures the dose for you and a vial makes you draw it. That is where the unit table above comes in — and where reaching for a U-40 syringe instead of a U-100 would put you 2.5 times out.

Dosage chart and titration schedule

The label schedule week by week, with the source on every row.

Tirzepatide side effects

Common and serious reactions, each quoted from the label.

These steps summarize the prescribing label. They do not replace the injection training the clinician or pharmacist who dispenses the product gives you, and nothing here recommends a dose.

Questions readers ask

How do I inject tirzepatide correctly?

The Zepbound label states it: under the skin of the stomach or thigh, at least 2 inches from the belly button. The site changes with every dose. It describes the back of the upper arm as an injection another person gives.

The label also names skin to leave out — pitted, thickened or lumpy skin, tender, bruised, scaly or hard skin, scars and damaged skin. Technique past that belongs with the prescriber, and this site adds nothing to the label.

Where's the best place to inject tirzepatide?

Its label lists the stomach and the thigh, and calls neither better. The back of the upper arm is on the list too, described as an injection somebody else gives.

The rule the label repeats is rotation. The same area of the body can come round again; the same spot cannot. Around the stomach it states a 2 inch clearance from the belly button, in inches only.

How long does it take for a shot of tirzepatide to kick in?

No published onset time was found. The half-life is about five days. That describes how long the drug remains, not when someone first notices an effect.

A half-life describes how long the drug takes to fall away, not how long it takes to start. The weight results here run over 72 weeks, not over hours.

What should I avoid while taking tirzepatide?

The label opens with a boxed warning. Rodents given tirzepatide developed thyroid C-cell tumors. The label rules the drug out after a personal or family history of medullary thyroid carcinoma or MEN 2.

It also flags low blood sugar alongside insulin or a sulfonylurea, and kidney injury after dehydration. On a missed dose it allows four days, and asks for at least 72 hours between doses. Anything past the label is a conversation with the prescriber.

Where to read next about tirzepatide

This page stops at the injection. These carry what happens either side of it.

The molecule behind Zepbound and Mounjaro

Published half-life: 5 days.

What the tirzepatide draw needs from the syringe scale

What a label allows, stated for the syringe scale rather than for tirzepatide.

How long Mounjaro keeps tirzepatide out of the fridge

Read off the Eli Lilly and Company label for Mounjaro rather than from tirzepatide in general.

Refrigerating the Zepbound carton of tirzepatide

3 device presentations, each with its own window rather than one tirzepatide figure for all of them.

What the tirzepatide draw needs from pen needles

What a label allows, stated for pen needles rather than for tirzepatide.

1primary source, each with the day we read it — open the documents used on this page

Zepbound (tirzepatide) — FDA-approved Prescribing Informationretrieved 2026-07-22FDA label