Tirzepatide Constipation: What to Expect on Compounded Tirzepatide
Yes, tirzepatide can cause constipation, and you're far from alone if it happens, whether you inject from a pen or a vial. In weight-loss trials of FDA-approved tirzepatide, 11–17% of people had constipation, compared with 5% on placebo, and it was actually least common at the highest dose (Zepbound prescribing information). Because it builds up over days, a record makes all the difference. Glapp, the GLP-1 tracker, lets you log constipation right next to your tirzepatide doses, so you can see how long each stretch lasts and whether it's easing.
Key numbers
| Number | What it means |
|---|---|
| 11–17% | of people on tirzepatide had constipation in weight-loss trials, vs 5% on placebo |
| 7,613 | users currently tracking tirzepatide-related constipation in Glapp |
Tirzepatide constipation: what the clinical evidence shows
The best evidence on tirzepatide comes from the FDA-approved versions, Zepbound and Mounjaro, which contain the same molecule. In the pooled weight-loss trials behind Zepbound's prescribing information (958 people on placebo, 2,519 on tirzepatide):
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Constipation | 5% | 17% | 14% | 11% |
Source: Zepbound prescribing information, Table 1.
Constipation is the one stomach side effect that didn't rise with dose in these trials: nausea, vomiting and diarrhea all climbed from 5 mg to 15 mg, while constipation fell from 17% to 11%. The trials report the pattern without explaining it.
Why does tirzepatide cause constipation?
GLP-1 medications like tirzepatide slow digestion, which is part of why you feel full. Slower movement through the gut can mean harder, less frequent stools. Eating much less also means less food, and often less fiber and fluid, passing through.
Fiber, fluids and movement: the three things that matter most
- Fiber. Most adults need around 25–30 g of fiber a day, and eating less often means getting far less. Vegetables, fruit, beans, oats and whole grains all count.
- Fluids. Fiber needs water to work; without enough, it can make things worse.
- Movement. Even a daily walk helps keep your gut moving.
Bloating and gas often come along with constipation. Severe or worsening stomach pain, vomiting, or being unable to pass stool or gas needs prompt medical attention.
Track your tirzepatide constipation with a GLP-1 tracker app
Constipation creeps up: by the time you notice, days have passed. A GLP-1 tracker keeps the record for you: log it each day next to your tirzepatide doses, and you're in control. You'll know how uncomfortable it gets and whether it's easing, and you'll walk into your next appointment with facts instead of guesses.
Why Glapp? It's a top-rated GLP-1 tracker used by 100,000+ people, rated 4.8/5 on Trustpilot and the App Store, and 4.6/5 on Google Play. Glapp grew out of Reddit GLP-1 support groups and is built by people who take GLP-1 medications themselves, which is why it handles the everyday side of compounded tirzepatide that brand-name pen trackers skip:
- Built-in dosage calculator. Glapp shows the units for the dose and concentration you enter. Confirm with your pharmacist.
- Vial and supply tracking. Every dose you log comes off your active vial, so you always know what's left, down to the unit.
It's grounded in published clinical trial data and peer-reviewed research, core tracking is free, and you get custom titration curves plus syncing across iPhone, Android and web. Here's how to use it over your first 30 days.
Glapp does not provide medical advice or treat side effects. It shows your daily check-ins against your estimated medication levels so you have structured data to share with your prescriber.
Day 1: Start tracking your constipation
Use Glapp's daily check-in to record constipation and rate how severe it feels. Log each dose too.
Daily entries help you see whether constipation is getting better, getting worse or staying the same. You'll have a clear record of how you felt, without having to remember every day.
Day 3: Compare symptoms with your estimated tirzepatide level
Glapp estimates your medication level throughout the day using your dose and injection time. Tirzepatide typically reaches its highest blood concentration 8–72 hours after an injection.
Seeing your symptoms alongside this estimate helps you spot when constipation appears within your shot cycle. As you log more days, you can look for a repeating pattern and know when to pay closer attention.
The medication level is an estimate, not a blood test, and a matching pattern does not prove what caused your symptoms.
Day 7: See how your constipation changes over time
Open the side-effects chart in the Progress tab and choose the period you want to review. Your daily ratings appear on a timeline, making it easier to see whether a difficult day was an isolated episode or part of a longer trend.
Day 14: Look for patterns in your weekly report
Glapp's weekly progress report brings your logged data together, with dedicated sections showing your side effects and how they change.
Does constipation tend to return on the same day after your shot? Did it change after a new vial or dose step? Does it coincide with changes in hunger or food noise? Reviewing two weeks of entries can help you spot patterns that are easy to miss day by day, and give you specific questions to discuss with your doctor.
Day 30: Bring a clear record to your doctor
After a month, review the bigger picture: is constipation becoming less frequent, staying the same or getting worse? Tirzepatide generally reaches a steady repeating level after about four weeks of weekly injections at the same dose.
Create a doctor's report in Glapp and choose the information to include. Your doctor can review your symptom history alongside your doses and progress, giving you a more focused conversation about your treatment.
Start tracking your tirzepatide constipation in Glapp
Constipation and dose steps on compounded tirzepatide: units, mg and why measuring matters
Tirzepatide usually starts at 2.5 mg once a week and steps up by 2.5 mg at least four weeks apart, to a maintenance dose between 5 and 15 mg. In the trials, constipation was 17% at 5 mg, 14% at 10 mg and 11% at 15 mg, so a higher dose doesn't automatically mean more constipation.
Tirzepatide from a vial is drawn up with a U-100 insulin syringe, where 1 unit = 0.01 mL. How many mg that holds depends on your vial's concentration:
mg = units × concentration (mg/mL) ÷ 100
| Dose | Units at 10 mg/mL | Units at 20 mg/mL |
|---|---|---|
| 2.5 mg | 25 | 12.5 |
| 5 mg | 50 | 25 |
| 7.5 mg | 75 | 37.5 |
| 10 mg | 100 | 50 |
| 12.5 mg | 125 | 62.5 |
| 15 mg | 150 | 75 |
Example concentrations only. Concentrations vary between pharmacies, so always use the concentration on your vial and your prescriber's or pharmacist's instructions. Over 100 units is more than a U-100 syringe holds. Ask your pharmacist.
If your side effects change sharply after a new vial, a new pharmacy or a new syringe size, check your concentration and units first, and call your prescriber or pharmacist.
What to bring to your prescriber
A simple log shows your prescriber the pattern at a glance:
| Week | Dose (mg / units) | Constipation days | Longest run of days | Peak rating | Other side effects logged |
|---|---|---|---|---|---|
| Example 1 | 5 mg / 50 units | 4 | 3 | Med | Bloating |
| Example 2 | 5 mg / 50 units | 5 | 4 | High | Bloating, flatulence |
| Example 3 | 5 mg / 50 units | 3 | 2 | Med | None |
| Example 4 | 5 mg / 50 units | 2 | 2 | Low | None |
Questions you could ask. They're conversation starters, not recommendations; your prescriber decides what, if anything, to change.
- "I've had constipation four days in a row this week. Is that expected on tirzepatide?"
- "Is there a laxative or fiber supplement you'd suggest with tirzepatide?"
- "Can you double-check my dose in units against my vial's concentration?"
Frequently asked questions
Does compounded tirzepatide cause more constipation than Zepbound or Mounjaro?
No trials compare them. When it's the same molecule, the same side effects are expected, but pharmacy-made versions can vary in strength, so logging your dose in mg helps you and your prescriber read your pattern correctly.
How long does tirzepatide constipation last?
It varies more than other stomach side effects. For many people it's worst in the first weeks and after a dose step, then improves as digestion adjusts and fiber, fluids and movement catch up. If you go more than three days without a bowel movement, or it keeps coming back, talk to your prescriber.
Does constipation get worse at higher tirzepatide doses?
Not in the trials: it was 17% at 5 mg, 14% at 10 mg and 11% at 15 mg, compared with 5% on placebo.
How do I track tirzepatide constipation?
Log it in Glapp's daily check-in and rate it low, medium or high, with your dose in mg. Progress shows your ratings over time, so you can see whether it's easing.
About the data
Ratings are self-reported and medication levels are estimated from dose and timing, not measured. This page is for information only and is not medical advice; talk to your prescriber about any side effect.
About the author
We're GLP-1 patients and health tech professionals, building Glapp in collaboration with doctors. About us
Sources
- Eli Lilly. Zepbound (tirzepatide) prescribing information: Table 1, warnings (severe gastrointestinal adverse reactions).
- U.S. Food and Drug Administration. FDA's concerns with unapproved GLP-1 drugs used for weight loss.