Zepbound Side Effects: What to Expect, How Long They Last and How to Track Them
The most common Zepbound side effects are nausea, diarrhea, constipation and vomiting, and for most people they're manageable and ease within the first weeks of each dose. In weight-loss trials, up to 29% of people on Zepbound had nausea, mostly while the dose was being increased, and more than 9 in 10 stayed on treatment (Zepbound prescribing information). Knowing what's normal takes most of the worry out of it. Glapp, the Zepbound progress tracker, lets you log every side effect right next to your Zepbound doses, so you can see what each shot does and watch it settle.
Key numbers
| Number | What it means |
|---|---|
| 25–29% | of people on Zepbound had nausea in weight-loss trials, the most common side effect, vs 8% on placebo |
| 18,657 | users currently tracking Zepbound side effects in Glapp |
| 4.8–6.7% | stopped Zepbound because of side effects, vs 3.4% on placebo |
Zepbound side effects: what the clinical trials show
Zepbound's prescribing information pools two placebo-controlled weight-loss trials (958 people on placebo, 2,519 on Zepbound). These are all the side effects reported by at least 2% of people and more often than on placebo:
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhea | 8% | 19% | 21% | 23% |
| Vomiting | 2% | 8% | 11% | 13% |
| Constipation | 5% | 17% | 14% | 11% |
| Abdominal pain | 5% | 9% | 9% | 10% |
| Indigestion (dyspepsia) | 4% | 9% | 9% | 10% |
| Injection site reactions | 2% | 6% | 8% | 8% |
| Fatigue | 3% | 5% | 6% | 7% |
| Allergic (hypersensitivity) reactions | 3% | 5% | 5% | 5% |
| Burping (eructation) | 1% | 4% | 5% | 5% |
| Hair loss | 1% | 5% | 4% | 5% |
| Acid reflux (GERD) | 2% | 4% | 4% | 5% |
| Gas (flatulence) | 2% | 3% | 3% | 4% |
| Bloating (abdominal distension) | 2% | 3% | 3% | 4% |
| Dizziness | 2% | 4% | 5% | 4% |
| Low blood pressure | 0% | 1% | 1% | 2% |
Source: Zepbound prescribing information, Table 1.
Most nausea, vomiting and diarrhea happened while the dose was being increased, and decreased over time. Severe stomach side effects were uncommon: 1.7–3.1% on Zepbound vs 1% on placebo. In SURMOUNT-1, people on tirzepatide, the molecule in Zepbound, lost 15–20.9% of their body weight over 72 weeks, vs 3.1% on placebo.
Common Zepbound side effects, one by one
Each of these has its own guide with the full data, the causes and a tracking plan.
- Nausea (25–29%). The most common side effect, usually worst in the first day or two after a shot and after each dose step. Full guide
- Diarrhea (19–23%). Mostly during dose escalation; fluids and electrolytes matter most. Full guide
- Vomiting (8–13%). Rises with dose and usually travels with nausea, so the nausea guide covers it. Full guide
- Constipation (11–17%). The one stomach side effect that was least common at the highest dose; fiber, fluids and movement help. Full guide
- Heartburn, indigestion and burping (4–10%). Slower stomach emptying keeps food in the stomach longer. Full guide
- Stomach pain, bloating and gas (3–10%). Usually mild and tied to the same slower digestion. Severe or lasting pain is different: call your prescriber.
- Fatigue (5–7%). Often linked to eating and drinking much less in the first weeks. Full guide
- Injection site reactions (6–8%). Redness, itching or bruising where the pen went in, usually gone within days. Full guide
- Hair loss (4–5%). Temporary shedding (telogen effluvium) that follows fast weight loss, usually a few months in. Full guide
- Dizziness and low blood pressure (1–5%). More likely when you're dehydrated or blood pressure falls as you lose weight.
- Headaches. Not among the common side effects in the trials, but often linked to dehydration and skipped meals. Full guide
- Long-term side effects. What changes after months on Zepbound, and what to watch for. Full guide
Why does Zepbound cause side effects?
Zepbound (tirzepatide) is a dual GIP and GLP-1 receptor agonist. It mimics two gut hormones, called incretins, that tell your brain you're full and slow how quickly your stomach empties (gastric emptying). Those same actions drive weight loss and explain most side effects:
- Slower gastric emptying. Food stays in the stomach longer, which brings fullness, nausea, burping, heartburn and, further down, constipation.
- Changes in gut movement. The gut needs time to adjust, which is why diarrhea, bloating and gas cluster in the first weeks.
- Eating much less. Lower appetite and less food noise mean fewer calories, less fluid and often less protein, which can bring tiredness, dizziness and, a few months in, hair shedding.
- Dose escalation. Every step up is a new adjustment period, so side effects tend to come back for a week or two after each increase and then settle.
How long do Zepbound side effects last?
For most people, Zepbound side effects are a phase, not a permanent state. They're strongest in the first one to two weeks after you start and after each dose increase, then ease as your body adjusts. Within each week, many people feel them most in the first one to three days after the shot: tirzepatide reaches its highest level a median of 24 hours after an injection (range 8–72 hours). Zepbound reaches a steady level after about four weeks at the same dose, which is why the fourth week on a dose usually feels calmer than the first.
| Side effect | How long it usually lasts | When to call your prescriber |
|---|---|---|
| Nausea | A day or two after each shot; eases over a few weeks at a stable dose | You can't keep food or fluids down |
| Diarrhea | A few days per episode, mostly during dose escalation | It lasts more than a couple of days, or comes with blood, fever or dizziness |
| Constipation | Can linger longer than other stomach side effects | No bowel movement for more than three days, or severe pain |
| Fatigue | The first weeks and after each dose step | It doesn't lift after a few weeks on the same dose |
| Injection site reactions | A few days | Redness spreads, feels hot, or lasts more than a week |
| Hair loss | Starts two to four months in; regrowth within six to twelve months | Shedding lasts more than six months or comes in patches |
Zepbound's half-life is about five days, so after a last dose it takes around a month to leave your body, and side effects fade over that time.
Track your Zepbound side effects with a Zepbound dose tracker and stay in control: your 30-day plan
Side effects are easier to handle when you can see them coming. That's what a GLP-1 tracking app is for: log how you feel each day next to your Zepbound doses, and you're in control. You'll know which day after your shot each side effect peaks, which dose step brought it on 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 app 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, so most of what's in it came straight from what the community asked for: daily side-effect check-ins, an estimated Zepbound level, custom titration curves for your dose steps and a doctor's report you can share. It's grounded in published clinical trial data and peer-reviewed research, core tracking is free, and it syncs 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 side effects
Use Glapp's daily check-in to record any side effect you notice, from nausea to tiredness, and rate how severe it feels. Log your Zepbound dose and injection time too, so everything that follows is based on what you actually took.
Daily entries help you see whether each side effect 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 Zepbound level
Glapp estimates your medication level throughout the day using your dose and injection time. Zepbound typically reaches its highest blood concentration 8–72 hours after an injection.
Seeing your symptoms alongside this estimate helps you spot when each side effect 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 side effects change 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.
Do side effects return on the same day after your shot? Did they start after a dose step? Do they 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: are your side effects becoming less frequent, staying the same or getting worse? Zepbound 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 and your next dose step.
Start tracking your Zepbound side effects in Glapp
Zepbound side effects by dose: what changes at each step
Zepbound starts at 2.5 mg once a week for four weeks, a starter dose rather than a treatment dose. After that it goes up in 2.5 mg steps, at least four weeks apart, to a maintenance dose of 5, 10 or 15 mg, with 15 mg as the maximum.
| 5 mg | 10 mg | 15 mg | |
|---|---|---|---|
| Nausea | 25% | 29% | 28% |
| Diarrhea | 19% | 21% | 23% |
| Vomiting | 8% | 11% | 13% |
| Constipation | 17% | 14% | 11% |
| Stopped because of any side effect | 4.8% | 6.3% | 6.7% |
| Stopped because of stomach side effects | 1.9% | 3.3% | 4.3% |
Placebo: 3.4% stopped because of any side effect, 0.5% because of stomach side effects. Source: Zepbound prescribing information.
Higher doses brought slightly more nausea, diarrhea and vomiting, but constipation went the other way. What matters most is timing: the weeks right after a step are when side effects are most likely, so that's when your check-ins are most useful.
What to bring to your prescriber
Glapp's doctor's report puts your side effects, doses and progress on one page. Before your appointment, check it shows:
- which side effects you had and how severe they were
- which day after your shot they peaked
- whether they started after a dose step
- any day you couldn't eat or keep fluids down
Questions you could ask. They're conversation starters, not recommendations; your prescriber decides what, if anything, to change.
- "My side effects peak a day or two after my shot. Is that expected on Zepbound?"
- "Should I stay on this dose longer before my next step?"
- "Which side effects should make me call you straight away?"
Frequently asked questions
How long do Zepbound side effects last?
For most people, a few weeks. Side effects are usually strongest in the first one to two weeks after starting and after each dose increase, peak in the first one to three days after each shot, and ease once you've been on the same dose for about four weeks. Hair shedding is the exception: it starts later and takes months to grow back.
What are the most common side effects of Zepbound?
Nausea (25–29%), diarrhea (19–23%), constipation (11–17%) and vomiting (8–13%) were the most common in weight-loss trials, followed by abdominal pain, indigestion, injection site reactions and fatigue.
When do Zepbound side effects start?
Often within the first day or two after your first shot or a dose increase, as tirzepatide reaches its peak level 8–72 hours after injection.
Do Zepbound side effects get worse with each dose increase?
They tend to come back for a week or two after each step. In the trials, nausea, diarrhea and vomiting were slightly more common at higher doses, while constipation was least common at 15 mg.
Do Zepbound side effects go away?
Yes, for most people. Most nausea, vomiting and diarrhea happened during dose escalation and decreased over time, and more than 9 in 10 people in the trials stayed on treatment.
Are Zepbound and Mounjaro side effects the same?
Yes. Both contain tirzepatide, so the same side effects are expected. Zepbound is the version approved for weight loss, and its trials are where the weight-loss side-effect rates come from. See Mounjaro side effects.
How do I track Zepbound side effects?
Log them in Glapp's daily check-in and rate each one low, medium or high, next to your Zepbound dose. Glapp shows each rating against your estimated medication level, and your weekly reports show which day after the shot each side effect peaks.
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 and precautions, dosage, pharmacokinetics.
- Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022;387:205–16. Trial summary.