Tirzepatide Side Effects: What to Expect in a Clinic Program

The label data in this guide come from Zepbound, Eli Lilly's branded tirzepatide, which is FDA-approved, alongside a reduced-calorie diet and increased physical activity, for weight reduction and long-term maintenance in adults with obesity or with overweight plus at least one weight-related condition, and for moderate to severe obstructive sleep apnea in adults with obesity.

Mounjaro is the same molecule, but it is approved for type 2 diabetes, not as a weight-loss product.

In the pooled Zepbound weight trials, gastrointestinal side effects occurred in 56% of patients on Zepbound versus 30% on placebo, and most nausea, vomiting and diarrhea happened during dose escalation and decreased over time.

The dose-by-dose rates the label reports were nausea (25–29% vs 8% on placebo), diarrhea (19–23% vs 8%), vomiting (8–13% vs 2%) and constipation (11–17% vs 5%), depending on dose.

The label's table also lists abdominal pain, dyspepsia (indigestion), injection-site reactions, fatigue, hypersensitivity, eructation (burping), hair loss and GERD (heartburn) among reactions reported at 5% or more in at least one dose group.

Hair loss, the cosmetic entry on that list, was reported in 4–5% of Zepbound-treated patients versus 1% on placebo in the weight-reduction trials.

The clearest timing signal in the label is that the majority of nausea, vomiting and diarrhea events occurred during dose escalation and decreased over time.

The labeled schedule starts low and steps up: treatment starts at 2.5 mg once weekly for 4 weeks — a starter dose only, not a maintenance dose — then 5 mg, with increases in 2.5 mg steps after at least 4 weeks on each dose.

For some patients the effects do not ease enough: across the pooled weight trials, 4.8% (5 mg), 6.3% (10 mg) and 6.7% (15 mg) of patients permanently stopped because of adverse reactions, versus 3.4% on placebo, mostly in the first few months and mostly because of GI effects.

Beyond that, the sources we cite do not give a week-by-week timeline for how long an individual's side effects last — we could not confirm a figure for how quickly nausea settles after a given dose increase, and if an effect is not easing, that is a question for your prescriber.

Beyond the common GI reactions, the Zepbound label carries warnings for severe GI reactions (it is not recommended in severe gastroparesis), acute kidney injury from dehydration, gallbladder disease, acute pancreatitis, serious allergic reactions, hypoglycemia when used with insulin or sulfonylureas, diabetic retinopathy complications, and pulmonary aspiration under anesthesia or deep sedation.

The label's gallbladder rates: cholelithiasis (gallstones) was reported in 1.1% of Zepbound-treated patients versus 1% on placebo, and cholecystitis (gallbladder inflammation) in 0.7% versus 0.2%.

The label also warns that Zepbound may reduce the effectiveness of oral birth control: it advises switching to a non-oral contraceptive method, or adding a barrier method, for 4 weeks after starting and for 4 weeks after each dose increase, and stopping Zepbound when pregnancy is recognized.

One warning changed: the label removed its "Suicidal Behavior and Ideation" warning in 02/2026, listed under Recent Major Changes.

Brand-name Zepbound is an FDA-approved drug, with the label data above reviewed for the indications the FDA approved it for.

Compounded drugs are different: FDA states that compounded drugs are not FDA-approved, that it does not review them for safety, effectiveness or quality before marketing, and that they should only be used in patients whose medical needs cannot be met by an FDA-approved drug.

FDA's adverse-event file on compounded GLP-1s is one window on the difference: as of May 31, 2026, the agency had received 990 adverse-event reports associated with compounded semaglutide and more than 730 with compounded tirzepatide — counts FDA says are likely underreported because 503A pharmacies are not required to report adverse events, and in which causation cannot always be determined.

They are report counts, not incidence rates, so they cannot be turned into a percentage.

FDA has also received adverse-event reports linked to compounded semaglutide or tirzepatide prescribed above label doses — larger doses, more frequent doses, or faster titration — some of them serious, and it recommends discarding a compounded multi-dose vial within 28 days of first use, even if medication remains.

Whether a med spa can lawfully give you a compounded GLP-1 in 2026, and under what limits, is its own question — our compounded GLP-1s guide covers it.

The label's warning list is the practical agenda for that conversation: severe GI reactions, acute kidney injury from dehydration, gallbladder disease, acute pancreatitis, serious allergic reactions, low blood sugar with insulin or sulfonylureas, diabetic retinopathy complications, and pulmonary aspiration under anesthesia or deep sedation.

Contact the prescriber who set your schedule about any effect that is severe or not easing, and seek emergency care for a severe reaction.

If you use oral contraceptives, the label's 4-week windows after starting and after each dose increase are worth confirming with the prescriber, and the label says to stop Zepbound when pregnancy is recognized.

Dose changes belong with the prescriber who set your schedule — the labeled steps increase by 2.5 mg no sooner than every 4 weeks, and the discontinuation rates above show that stopping is a real outcome for a share of patients.

If what you were given is not brand-name Zepbound, say so: FDA's adverse-event reports on compounded GLP-1s include events tied to above-label dosing.

Zepbound is prescription-only: it requires a valid prescription from a licensed prescriber, and FDA tells patients to fill prescriptions at state-licensed pharmacies.

A supervised program is one where a licensed prescriber evaluates you first, sets the titration schedule within the labeled steps, and stays reachable for the conversations above as your dose changes.

Who may prescribe and supervise these drugs at a med spa — a physician, NP or PA, with an on-site exam versus telehealth — is set by state law, not by the FDA label; our page on who can prescribe GLP-1s explains them.

For what tirzepatide is, how it works and what programs charge per month, start with the tirzepatide guide.