Tirzepatide is taken once a week, on the same day each week. You start at the lowest dose (2.5 mg) and gradually increase every four weeks until you and your prescriber find the dose that works best for you. The maximum dose is 15 mg per week.
The Weekly Dosing Schedule
Every tirzepatide regimen follows the same pattern. You inject 2.5 mg once a week for the first four weeks. This starting dose isn’t really meant to produce significant weight loss or blood sugar changes. It’s a ramp-up period that lets your body adjust to the medication and reduces the chance of stomach-related side effects.
After those first four weeks, your dose increases to 5 mg once weekly. From there, your prescriber may raise it in 2.5 mg steps, but never sooner than four weeks on each dose. The available maintenance doses are 5 mg, 10 mg, and 15 mg. Not everyone needs to go to the highest dose. Some people get good results at 5 mg or 10 mg and stay there long-term.
For obstructive sleep apnea specifically, the recommended maintenance range is 10 mg or 15 mg weekly.
Why Once a Week Works
Tirzepatide has a half-life of about five days, meaning it takes roughly five days for your body to clear half of a single dose. That slow breakdown keeps the drug active in your system throughout the week, which is why you only need one injection every seven days rather than daily shots. The medication level stays relatively steady between doses, so you get consistent appetite suppression and blood sugar control without daily peaks and valleys.
Picking a Day and Time
You can choose any day of the week for your injection, but once you pick one, stick with it. There’s no clinical requirement to take it at a specific time of day or with food. That said, many people find that injecting in the evening, roughly two hours after a light dinner, helps them sleep through the initial wave of nausea that some experience. If you’re prone to insomnia, a morning injection may work better. Eating a small, protein-rich meal before your injection can also help stabilize blood sugar and reduce lightheadedness.
What to Do If You Miss a Dose
If you miss your scheduled injection day, take it as soon as you remember, as long as your next scheduled dose is at least four days (96 hours) away. If it’s fewer than four days until your next dose, skip the missed one entirely and resume your normal weekly schedule. Don’t double up to make up for a missed week.
How to Handle Side Effects During Dose Increases
Nausea, diarrhea, and reduced appetite are the most common side effects, and they tend to be worst in the first few days after each dose increase. The four-week minimum between increases exists specifically to let these symptoms settle before adding more medication. If side effects are still bothering you at the end of four weeks on a given dose, there’s no rule that forces you to move up. You can stay at your current dose longer, or your prescriber may decide your current level is the right maintenance dose.
Staying hydrated and eating smaller, more frequent meals in the days following each injection can help manage nausea. Some people notice that side effects are strongest on days one and two after the shot, then taper off by mid-week.
Where and How to Inject
Tirzepatide is a subcutaneous injection, meaning the needle goes just under the skin. The three recommended sites are your abdomen (at least two inches from your belly button), the front of your thighs, or the outer part of your upper arm. Rotate between these sites each week to avoid skin irritation or changes in the fat tissue under the skin.
The medication comes in a pre-filled pen, so you don’t need to measure or draw up a dose. Each pen is single-use.
Storing Your Pens
Unused pens should be kept in the refrigerator. If you need to carry one with you or prefer it at room temperature, a pen can safely stay unrefrigerated for up to 21 days. After that window, throw it away even if it hasn’t been used. Once a pen has been stored at room temperature, don’t put it back in the fridge.
Why Staying on Schedule Matters
Consistency matters with tirzepatide. In the phase 3 SURMOUNT-4 trial, patients who used tirzepatide for 36 weeks lost an average of 21% of their body weight. When they were switched to a placebo, they regained about 14% over the following year. Keeping your weekly schedule steady helps maintain both the weight loss and metabolic benefits the medication provides.