Mounjaro is taken once a week, on the same day each week, at any time of day. There’s no requirement to take it with or without food. You start at the lowest dose and gradually increase over several months, so the full dosing schedule involves more than just picking a day.
The Weekly Schedule
You inject Mounjaro once every seven days. Pick whichever day works best for your routine. Morning, afternoon, evening: it doesn’t matter. The medication stays active in your body for about five days (its elimination half-life), which is why once-weekly dosing keeps levels steady without needing daily injections.
If you need to change your injection day, you can, as long as at least 72 hours (three full days) have passed since your last dose. So if you normally inject on Mondays but want to switch to Thursdays, you’d just make sure those three days have elapsed before taking your next dose. After that, Thursday becomes your new regular day.
How the Dose Increases Over Time
Everyone starts at 2.5 mg once weekly. This isn’t a treatment dose. It’s designed to let your body adjust to the medication and minimize side effects like nausea. You stay at 2.5 mg for four weeks.
After those first four weeks, the dose increases to 5 mg once weekly. From there, your doctor may continue increasing in 2.5 mg steps, with at least four weeks at each level before moving up. The available doses are 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. The maximum dose for adults is 15 mg per week.
Not everyone needs the highest dose. Some people reach their treatment goals at 5 mg or 10 mg and stay there. Each increase is based on how well the current dose is working and how well you’re tolerating it. The entire ramp-up from 2.5 mg to 15 mg takes a minimum of 20 weeks if you increase at every opportunity, though many people take longer.
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 it’s within four days of when you were supposed to inject. If more than four days have passed, skip that dose entirely and take your next one on the regularly scheduled day. Never double up by taking two doses in one week.
For example, if your injection day is Monday and you forget until Wednesday, go ahead and inject Wednesday. But if you don’t remember until Saturday, skip it and wait for the following Monday.
Where and How to Inject
Mounjaro goes under the skin (subcutaneously) using a pre-filled pen. You have three options for injection sites:
- Abdomen: At least 2 inches away from your belly button, avoiding the belt line area.
- Thigh: The middle third of the front of your thigh.
- Upper arm: The back of the upper arm, though you’ll likely need someone else to inject this spot for you.
Rotate your injection site each week. Using the same spot repeatedly increases the risk of skin irritation or tissue changes at that location. You can alternate between the three areas, or move to different spots within the same area from week to week.
Storing the Pen Between Doses
Mounjaro pens should be kept in the refrigerator until you’re ready to use them. If refrigeration isn’t available, an unused pen can be stored at room temperature (up to 86°F / 30°C) for up to 30 days. After 30 days at room temperature, the pen should be discarded even if it hasn’t been used. Don’t freeze the pens, and keep them out of direct sunlight or extreme heat.
Tips for Staying on Schedule
Since the injection is only once a week, it’s easy to lose track. Setting a recurring weekly alarm on your phone is the simplest fix. Some people tie the injection to a specific routine, like every Sunday evening before bed, to build it into their week naturally.
If you’re experiencing significant nausea or other side effects at a new dose level, talk to your prescriber before your next increase. Staying at the current dose for longer than four weeks is common and doesn’t reduce the medication’s long-term effectiveness. The four-week minimum between increases is a floor, not a deadline.