Zepbound side effects: rates by dose and when to get help
By Iacob Pastina, independent researcher & publisher · Updated September 8, 2026
Zepbound commonly causes nausea, diarrhea, constipation and vomiting. In the pooled weight-management trials, nausea affected 25–29% of people assigned Zepbound, compared with 8% on placebo. Rates differ by assigned dose and symptom; they do not predict what will happen at each step of your own treatment. Most nausea, vomiting and diarrhea events occurred during dose increases and became less frequent over time. There is no guaranteed week when symptoms stop. Severe or persistent abdominal pain, trouble breathing, or ongoing vomiting with dehydration needs prompt medical attention. Use the dose table below to understand the evidence, then bring your symptoms to your prescriber before changing treatment. Source: Zepbound prescribing information, sections 5 and 6.1.
Educational information, not medical advice. This independently researched guide has not been medically reviewed by a clinician. AI assistance was used to organize the source comparison.
Which Zepbound side effects need urgent help?
- Trouble breathing or swelling of the face, lips, tongue or throat: stop using Zepbound and get emergency medical help. Call 911 for breathing difficulty or collapse.
- Severe abdominal pain that does not go away, possibly reaching the back: stop Zepbound and contact a healthcare professional immediately; this can signal pancreatitis, with or without vomiting.
- Vomiting or diarrhea that persists, inability to drink, or markedly reduced urination: seek prompt medical advice for possible dehydration and kidney injury. Do not wait for a fixed 24-hour threshold.
- Upper abdominal pain with fever, jaundice or pale stools: contact your clinician right away for possible gallbladder problems.
- Severe confusion, fainting or a seizure: seek emergency help. Low blood sugar is a particular concern with insulin or sulfonylureas; follow the treatment plan your clinician gave you.
These warning signs come from the FDA-approved Medication Guide. They are not a diagnosis or a complete list of possible adverse effects.
What are the common Zepbound side effects by dose?
The table shows the percentage of adults reporting each reaction in pooled Studies 1 and 2, as listed in section 6.1, Table 1 of the prescribing information. The groups included 958 placebo participants and 630, 948 and 941 participants assigned to 5, 10 and 15 mg respectively.
| 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 | 4% | 9% | 9% | 10% |
| Injection site reactions | 2% | 6% | 8% | 8% |
| Fatigue | 3% | 5% | 6% | 7% |
| Hair loss | 1% | 5% | 4% | 5% |
| Heartburn / reflux | 2% | 4% | 4% | 5% |
These are treatment-group totals, not measurements of the same person moving through each dose. Constipation was reported less often in the higher-dose groups; that does not establish that increasing your dose will relieve constipation. The table does not supply separate rates for the 2.5 mg starter dose or the 7.5 and 12.5 mg escalation steps. It also cannot establish that Zepbound is safer than another medicine studied in a different trial.
How long do Zepbound side effects last?
The label, section 6.1, reports that most nausea, vomiting and diarrhea events occurred during dose escalation and decreased over time. It does not give a reliable day-by-day prediction or promise that symptoms disappear after a certain number of weeks. Persistent or severe symptoms deserve assessment even after months of treatment.
The labeled starting dose is 2.5 mg weekly for four weeks, followed by 5 mg. Further increases are in 2.5 mg steps after at least four weeks on the current dose, guided by response and tolerability. For weight management, recommended maintenance doses are 5, 10 or 15 mg; not everyone needs 15 mg. The 7.5 and 12.5 mg strengths are escalation steps, not the label's recommended maintenance doses. See the Zepbound dosage guide for dose terminology.
GI reactions led 1.9%, 3.3% and 4.3% of the 5, 10 and 15 mg groups to stop treatment, versus 0.5% with placebo. Discontinuation for any adverse reaction was higher: 4.8%, 6.3% and 6.7%, versus 3.4%. A low GI discontinuation rate does not mean everyone else had no symptoms or completed the study.
Does Zepbound cause hair loss?
Hair loss was reported by 4–5% of Zepbound participants and 1% of placebo participants in the pooled trials. The label's hair-loss analysis in section 6.1 associates these reports with weight reduction and records a higher rate in female than male participants. It does not establish the cause of any individual's hair loss or guarantee regrowth by a specific month. Ask your clinician to assess new or persistent shedding and whether your nutritional intake needs attention; do not assume a supplement or a particular protein target is appropriate for everyone.
What other warnings should I discuss before treatment?
The boxed warning concerns thyroid C-cell tumors observed in rats; the human risk is unknown. Zepbound is contraindicated with a personal or family history of medullary thyroid carcinoma, MEN 2, or a serious allergy to tirzepatide or its ingredients. Report a neck lump, persistent hoarseness or difficulty swallowing. The prescribing information, sections 4 and 5, also says it is not recommended with severe gastroparesis.
Tell your care team about insulin or sulfonylureas, vision changes, pregnancy, and any planned anesthesia or deep sedation. Oral contraceptives may be less effective: the label advises a non-oral method or an added barrier method for four weeks after starting and after each dose increase. Your prescriber should review your medicines and contraceptive plan with you.
Older guides may list suicidal thoughts as a Zepbound warning. On January 13, 2026, FDA requested removal of that warning after its review found no increased risk with GLP-1 medicines. Regardless of cause, seek immediate support for thoughts of self-harm; in the US, call or text 988, or call 911 if there is immediate danger.
What should I tell my prescriber about side effects?
The Medication Guide advises discussing symptoms that bother you or do not go away. For a routine appointment or message, copy this checklist and fill it in:
- My current dose, last injection date, and date of the most recent increase.
- Which symptoms started, when they occur, and whether they are improving.
- Whether I can eat and drink, and whether urination has changed.
- All medicines and supplements I take, including any symptom remedies.
- My question: should we reassess the next dose increase or the treatment plan?
Ask your prescriber or pharmacist which nausea or constipation treatment is suitable for you before adding one. Follow your prescribed dosing and hydration advice; do not use an online timetable to push through worsening symptoms. If any urgent warning sign above is present, seek care instead of waiting for a routine reply.
Read the wider GLP-1 side-effects guide · Browse the Safety Center
Source method: dose rates and warnings checked against Lilly's current US label and August 2026 Medication Guide on September 8, 2026. This page replaces our earlier blog guide so readers have one maintained Zepbound side-effects reference.