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tirzepatide

Sold as Mounjaro, Zepbound. First FDA approval 05/13/2022: 4 years on the US market.

This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.

D

Score breakdown (54/100)

Safety ×35%
D
Evidence ×25%
B
Regulatory ×15%
B
Money & lawsuits ×15%
F
Options ×10%
F

Safety: 51

Evidence: 75

Regulatory history: 77

Money & lawsuits: 15

Options: 40

FDA boxed warning

WARNING: RISK OF THYROID C-CELL TUMORS In rats, tirzepatide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures. It is unknown whether ZEPBOUND causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined [see Warnings and Precautions ( 5.1 ) and Nonclinical Toxicology ( 13.1 )]. ZEPBOUND is contraindicated in patients with a personal or family history of MTC or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) [see Contraindications ( 4 )] . Counsel patients regarding the potential risk for MTC with the use of ZEPBOUND and inform them of symptoms of thyroid tumors (e.g., a mass in the neck, dysphagia, dyspnea, persistent hoarseness). Routine monitoring of serum calcitonin or using thyroid ultrasound is of uncertain value for early detection of MTC in patients treated with ZEPBOUND [see Contraindications ( 4 ) and Warnings and Precautions ( 5.1 )]. WARNING: RISK OF THYROID C-CELL TUMORS See full prescribing information for complete boxed warning. In rats, tirzepatide causes thyroid C-cell...

Independent reviews and post-approval warnings

FDA Drug Safety Communications

Warnings the FDA chose to announce publicly after approval, as opposed to quiet label edits. Class-wide items name the drug's class, not this drug specifically.

WHO Essential Medicine

Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.

What the FDA label says

Approved uses

® is indicated in combination with a reduced-calorie diet and increased physical activity: to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition. to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity. ZEPBOUND is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist indicated in combination with a reduced-calorie diet and increased physical activity: to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition. ( 1 ) to treat moderate to severe obstructive sleep apnea (OSA) in adults with obesity. ( 1 ) Limitations of Use: Coadministration with other tirzepatide-containing products or with any GLP-1 receptor agonist is not recommended. ( 1 ) Limitations of Use ZEPBOUND contains tirzepatide. Coadministration with other tirzepatide-containing products or with any glucagon-like peptide-1 (GLP-1) receptor agonist is not recommended.

Contraindications

is contraindicated in patients with: A personal or family history of MTC or in patients with MEN 2 [see Warnings and Precautions ( 5.1 )] . Known serious hypersensitivity to tirzepatide or any of the excipients in ZEPBOUND. Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported with tirzepatide [see Warnings and Precautions ( 5.6 ) and Adverse Reactions ( 6.2 )] . Personal or family history of medullary thyroid carcinoma or in patients with Multiple Endocrine Neoplasia syndrome type 2 ( 4 ) Known serious hypersensitivity to tirzepatide or any of the excipients in ZEPBOUND ( 4 )

Warnings and precautions

Severe Gastrointestinal Adverse Reactions: Use has been associated with gastrointestinal adverse reactions, sometimes severe. ZEPBOUND is not recommended in patients with severe gastroparesis. ( 5.2 ) Acute Kidney Injury Due to Volume Depletion: Monitor renal function in patients reporting adverse reactions that could lead to volume depletion. ( 5.3 ) Acute Gallbladder Disease: Has been reported in clinical trials. If cholecystitis is suspected, gallbladder studies and clinical follow-up are indicated. ( 5.4 ) Acute Pancreatitis: Has been observed in patients treated with GLP-1 receptor agonists, or ZEPBOUND. Discontinue if pancreatitis is suspected. ( 5.5 ) Hypersensitivity Reactions: Serious hypersensitivity reactions (e.g., anaphylaxis, angioedema) have been reported postmarketing with tirzepatide. If suspected, advise patients to promptly seek medical attention and discontinue ZEPBOUND. ( 5.6 ) Hypoglycemia: Concomitant use with insulin or an insulin secretagogue may increase the risk of hypoglycemia, including severe hypoglycemia. Reducing dose of insulin or insulin secretagogue may be necessary. Inform all patients of the risk of hypoglycemia and educate them on the signs and...

Adverse reactions (label)

The following serious adverse reactions are described below or elsewhere in the prescribing information: Risk of Thyroid C-cell Tumors [see Warnings and Precautions ( 5.1 )] Severe Gastrointestinal Adverse Reactions [see Warnings and Precautions ( 5.2 )] Acute Kidney Injury Due to Volume Depletion [see Warnings and Precautions ( 5.3 )] Acute Gallbladder Disease [see Warnings and Precautions ( 5.4 )] Acute Pancreatitis [see Warnings and Precautions ( 5.5 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.6 )] Hypoglycemia [see Warnings and Precautions ( 5.7 )] Diabetic Retinopathy Complications in Patients with Type 2 Diabetes Mellitus [see Warnings and Precautions ( 5.8 )] Pulmonary Aspiration During General Anesthesia or Deep Sedation [see Warnings and Precautions ( 5.9 )] The most common adverse reactions, reported in ≥5% of patients treated with ZEPBOUND are: nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, injection site reactions, fatigue, hypersensitivity reactions, eructation, hair loss, gastroesophageal reflux disease. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Eli Lilly and Company at 1-800-LillyRx (1-800-545-5979) or FDA at 1-8...

Recent major label changes

Dosage and Administration ( 2.4 ) 01/2026 Warnings and Precautions Severe Gastrointestinal Adverse Reactions ( 5.2 ) 02/2026 Diabetic Retinopathy Complications in Patients with Type 2 Diabetes Mellitus ( 5.8 ) 08/2026 Suicidal Behavior and Ideation (Removed) 02/2026 Never Share a ZEPBOUND KwikPen Between Patients ( 5.10 ) 01/2026

Source: FDA SPL label for Zepbound (Eli Lilly and Company), effective 20260828. Full label on DailyMed.

Side-effect reports sent to the FDA

These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.

160,657reports that mention this drug
160,195of those blame this drug, not another one the person was taking
18%of reports describe a serious outcome, such as a hospital stay (average for all drugs: 57%)
0.6%of reports include a death, from any cause (average for all drugs: 9.1%)

Problems reported most often

Incorrect Dose Administered · 29,672Nausea · 17,091Injection Site Pain · 13,905Diarrhoea · 10,006Extra Dose Administered · 9,608Off Label Use · 8,941Vomiting · 8,267Drug Ineffective · 6,965Constipation · 6,502Injection Site Haemorrhage · 5,281Injection Site Erythema · 5,210Fatigue · 4,771Accidental Underdose · 4,609Product Dose Omission Issue · 4,474Abdominal Pain Upper · 3,709

Reports per year

20192020202120222023202420252026
2733355,05120,80033,04562,30239,347

26,297 reports blaming this drug for every million Medicare prescriptions filled, which is 9.5× the typical drug on this site. (134,264 reports in 2024–2026, against 5,105,750 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)

Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.

Recalls and regulatory record

0recall actions on file
2 / 0brand / generic applications
17label changes since 2021
NoREMS program

Evidence base

126randomized trials (PubMed)
91systematic reviews
307registered trials
52%of completed trials posted results
2%terminated or withdrawn
47%industry-funded

Independent Cochrane reviews

Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.

Money and lawsuits

In 2024, drug companies reported $17,446,963 in payments to US physicians and hospitals tied to this drug across 262,958 transactions (Mounjaro $12,625,761, Zepbound $4,821,202).

Pending federal multidistrict litigation

Not named in any federal pharmaceutical settlement of $100M or more on record.

Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.

Who takes it and what it costs

894,826Medicare Part D patients (2024)
5,105,750prescriptions filled
$1,241average cost per fill
$6,337Mtotal Medicare spend
ProductFills$/fill
Mounjaro5,105,397$1,241
Zepbound353$1,097

Same-class alternatives

No same-class alternatives found in RxClass.

Questions to ask your prescriber

  1. This drug carries a boxed warning. Which specific risk does it cover, and does it apply to me?
  2. The most-reported problems in FDA's adverse event data are incorrect dose administered, nausea, injection site pain, diarrhoea. How would we recognize and handle those?
  3. Off-label use is among the most-reported items for this drug. Is my use on-label, and if not, what evidence supports it?
  4. There is no generic. Is there an older generic in the same class that works as well for my situation?
  5. The manufacturer pays physicians heavily to promote this drug. Have you received anything from them?
  6. This drug is in active federal litigation. What is the claim, and does it affect my risk?
  7. What result are we expecting, by when, and what is the plan if it does not happen?
  8. If 100 people like me took this drug, how many would actually get better because of it, and how many would be harmed by it? (Doctors call these the number needed to treat and the number needed to harm.)