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Peptide Spencer

Dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist

Tirzepatide

Also known as LY3298176, Zepbound, Mounjaro

FDA-approved productTier A applies to the molecule and its label titration (phase 3 trials SURMOUNT-1, SURMOUNT-4, SURMOUNT-OSA, SURPASS-1 and SURPASS-2). The formulary product is compounded and unapproved. FDA declared the shortage resolved, and tirzepatide is on neither the shortage list nor the 503B bulks list. Practice dosing adds no evidence beyond the label.

FDA-approved as Zepbound and Mounjaro. Compounded tirzepatide is not FDA-approved. Source, Aug 28, 2026

Identity. Tirzepatide is the dual GIP/GLP-1 receptor agonist marketed by Eli Lilly as Zepbound (weight management, obstructive sleep apnea) and Mounjaro (type 2 diabetes). Compounded products are not FDA-approved and may differ in concentration and salt form. Vial concentration varies by pharmacy. Always confirm mg/mL on the dispensed label before converting any dose to volume or syringe units. Formulary items (10 to 180 mg vials) are compounded multi-dose products, not Zepbound or Mounjaro. The largest FDA-approved multi-dose presentation is 60 mg/2.4 mL (25 mg/mL, four doses).

At a glance

These dosages are a helpful guide, not a prescription. Every clinician is expected to do their own due diligence before prescribing.

  1. Start

    2.5 mg subcutaneously once weekly for 4 weeks1

    Approved label

  2. Typical

    5 mg, 10 mg, or 15 mg once weekly (Zepbound weight); OSA 10 mg or 15 mg1

    Approved label

  3. Ceiling

    15 mg once weekly in adults; 10 mg once weekly in pediatric patients (Mounjaro)12

    Approved label
Frequency
once weekly1
Route
subcutaneous injection1
Course
5 mg after 4 weeks; 2.5 mg steps after at least 4 weeks on current dose1

Boxed warning for thyroid C-cell tumors (contraindicated with MTC or MEN 2 history); compounded mg/mL varies, so confirm concentration before converting to volume.

Calculate this dose

Dosing detail

Approved label

Approved label

  • Zepbound, adults with obesity or overweight (weight reduction and maintenance): initiation

    2.5 mg1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Duration
    4 weeks (initiation only)
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    The recommended starting dosage of ZEPBOUND for all indications is 2.5 mg injected subcutaneously once weekly for 4 weeks. The 2.5 mg dosage is for treatment initiation and is not approved as a maintenance dosage.

    Finding. Starting dose. The 2.5 mg dose is for treatment initiation and is not approved as a maintenance dosage.

  • Zepbound, escalation after initiation

    5 mg after the first 4 weeks, then increase in 2.5 mg increments mg1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Duration
    each step at least 4 weeks on current dose
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    After 4 weeks, increase the dosage to 5 mg injected subcutaneously once weekly. The dosage may be increased in 2.5 mg increments, after at least 4 weeks on the current dose

    Finding. The first step after 2.5 mg is 5 mg. Further increases are in 2.5 mg increments, no sooner than every 4 weeks, until the maintenance dosage is reached. If a maintenance dosage is not tolerated, consider a lower maintenance dosage.

  • Zepbound, maintenance for weight reduction (10 or 15 mg for obstructive sleep apnea)

    5; 10; 15 mg1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Duration
    long-term maintenance
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    Weight Reduction and Long-Term Maintenance The recommended maintenance dosage is 5 mg, 10 mg, or 15 mg, injected subcutaneously once weekly. OSA The recommended maintenance dosage is 10 mg or 15 mg injected subcutaneously once weekly.

    Finding. Weight reduction maintenance is 5, 10 or 15 mg. Obstructive sleep apnea maintenance is 10 mg or 15 mg.

  • Zepbound, maximum dosage, all indications

    15 mg1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    The maximum dosage of ZEPBOUND for all indications is 15 mg injected subcutaneously once weekly.

    Finding. The label maximum is 15 mg once weekly for every indication.

  • Zepbound, missed dose and changing the dosing day

    administer as soon as possible within 4 days (96 hours); skip if more than 4 days days (96 hours)1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    If a dose is missed, instruct patients to administer ZEPBOUND as soon as possible within 4 days (96 hours) after the missed dose. If more than 4 days have passed, skip the missed dose and administer the next dose on the regularly scheduled day. The day of weekly administration can be changed, if necessary, as long as the time between the two doses is at least 3 days (72 hours).

    Finding. Give a missed dose as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and give the next dose on the regular day. The weekly day may be changed if at least 3 days (72 hours) separate the two doses.

  • Zepbound, approved vial administration

    0.5 mL or 0.6 mL per dose with the approved 4-dose multi-dose vial mL1

    Route
    subcutaneous injection
    Frequency
    once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    Instruct patients using ZEPBOUND vials to use a syringe appropriate for dose administration (e.g., a 1 mL syringe capable of measuring a 0.5 mL or 0.6 mL dose) and always use a new syringe and needle for each injection.

    Finding. Approved vials deliver each dose in 0.5 to 0.6 mL (strengths 10 to 60 mg/2.4 mL, four doses each). Use a 1 mL syringe, and a new syringe and needle for every injection.

  • Mounjaro, type 2 diabetes: initiation

    2.5 mg2

    Route
    subcutaneous injection
    Frequency
    once weekly
    Duration
    4 weeks (initiation only), then increase to 5 mg once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    The 2.5 mg dosage is for treatment initiation and is not intended for glycemic control. After 4 weeks, increase the dosage to 5 mg injected subcutaneously once weekly.

    Finding. The 2.5 mg dose is for initiation and is not intended for glycemic control. After 4 weeks the dose goes to 5 mg once weekly.

  • Mounjaro, type 2 diabetes: escalation

    increase in 2.5 mg increments, only if additional glycemic control is needed mg2

    Route
    subcutaneous injection
    Frequency
    once weekly
    Duration
    each step at least 4 weeks on current dose
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    If additional glycemic control is needed, increase the dosage in 2.5 mg increments after at least 4 weeks on the current dose.

    Finding. Steps above 5 mg are used only if additional glycemic control is needed, and each follows at least 4 weeks on the current dose.

  • Mounjaro, type 2 diabetes in adults: maximum dosage

    15 mg2

    Route
    subcutaneous injection
    Frequency
    once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    15 mg injected subcutaneously once weekly in adults.

    Finding. The adult maximum is 15 mg once weekly.

  • Mounjaro, pediatric patients 10 years and older with type 2 diabetes: maximum dosage

    10 mg2

    Route
    subcutaneous injection
    Frequency
    once weekly
    Design
    FDA-approved labeling, Dosage and Administration
    Source quote
    10 mg injected subcutaneously once weekly in pediatric patients.

    Finding. The pediatric maximum is 10 mg once weekly, 1.5-fold below the adult maximum. Giving 15 mg to a patient aged 10 to 17 years exceeds the labeled maximum. The Mounjaro KwikPen is not recommended for self-administration by pediatric patients.

Human studies

Human study

  • SURMOUNT-1: adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes

    5; 10; 15 mg3

    Route
    subcutaneous
    Frequency
    once weekly
    Duration
    72 weeks, including a 20-week dose-escalation period
    n
    2539
    Design
    Phase 3 double-blind randomized placebo-controlled trial
    Source quote
    we assigned 2539 adults with a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 30 or more, or 27 or more and at least one weight-related complication, excluding diabetes, in a 1:1:1:1 ratio to receive once-weekly, subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 72 weeks, including a 20-week dose-escalation period.

    Finding. Mean weight change at week 72: -15.0% (5 mg), -19.5% (10 mg), -20.9% (15 mg) versus -3.1% placebo.

  • SURMOUNT-4: randomized withdrawal after a 36-week open-label lead-in at maximum tolerated dose (10 or 15 mg), adults with obesity or overweight, excluding diabetes

    10 or 15 (maximum tolerated dose) mg4

    Route
    subcutaneous
    Frequency
    once weekly
    Duration
    36-week lead-in then 52-week double-blind period (week 88)
    n
    783 enrolled in lead-in; 670 randomized
    Design
    Phase 3 randomized withdrawal clinical trial
    Source quote
    The mean percent weight change from week 36 to week 88 was -5.5% with tirzepatide vs 14.0% with placebo (difference, -19.4% [95% CI, -21.2% to -17.7%]; P < .001).

    Finding. Lead-in mean weight reduction 20.9%. Week 36 to 88 weight change was -5.5% with continued tirzepatide versus +14.0% after switching to placebo; 89.5% vs 16.6% maintained at least 80% of lead-in weight loss.

  • SURMOUNT-OSA: two trials in adults with moderate-to-severe obstructive sleep apnea and obesity (supports the OSA indication and its 10 or 15 mg maintenance)

    10 or 15 (maximum tolerated dose) mg5

    Route
    not stated in abstract
    Frequency
    not stated in abstract
    Duration
    52 weeks
    n
    not stated in abstract
    Design
    Two phase 3 double-blind randomized controlled trials
    Source quote
    The participants were assigned in a 1:1 ratio to receive either the maximum tolerated dose of tirzepatide (10 mg or 15 mg) or placebo for 52 weeks.

    Finding. Mean change in AHI at week 52: -25.3 events/h (trial 1) and -29.3 events/h (trial 2) with tirzepatide versus -5.3 and -5.5 with placebo.

  • SURPASS-2: type 2 diabetes, tirzepatide versus semaglutide 1 mg

    5; 10; 15 mg6

    Route
    not stated in abstract (subcutaneous per label)
    Frequency
    once weekly (per article title)
    Duration
    40 weeks
    n
    1879
    Design
    Open-label phase 3 randomized trial
    Source quote
    In an open-label, 40-week, phase 3 trial, we randomly assigned 1879 patients, in a 1:1:1:1 ratio, to receive tirzepatide at a dose of 5 mg, 10 mg, or 15 mg or semaglutide at a dose of 1 mg.

    Finding. HbA1c change -2.01, -2.24, -2.30 percentage points (5, 10, 15 mg) versus -1.86 with semaglutide.

  • SURPASS-1: type 2 diabetes inadequately controlled by diet and exercise, monotherapy versus placebo

    5; 10; 15 mg7

    Route
    not stated in abstract (subcutaneous per label)
    Frequency
    once a week
    Duration
    40 weeks
    n
    478
    Design
    Phase 3 double-blind randomized placebo-controlled trial
    Source quote
    Participants were randomly assigned (1:1:1:1) via computer-generated random sequence to once a week tirzepatide (5, 10, or 15 mg), or placebo.

    Finding. HbA1c fell 1.87% (5 mg), 1.89% (10 mg), 2.07% (15 mg) versus +0.04% with placebo.

What clinics and vendors publish

These ranges come from clinic and vendor publications, not studies.

Clinic-reportedCommunity-reported

Practice dosing for tirzepatide follows the FDA label titration. The available practice sources are a manufacturer medical-information page, a consumer drug-information page and a trial protocol. They restate the label and report no independent practice data. FDA reports adverse events involving doses beyond the label, and more than 730 reports tied to compounded tirzepatide as of May 31, 2026. No source supports a dose above 15 mg once weekly. Compounded concentration varies, so confirm the dispensed mg/mL before converting to volume or units. Coadministration with other tirzepatide products or any GLP-1 receptor agonist is not recommended.

StartClinic-reported
2.5 mg once weekly for 4 weeks
TitrationClinic-reported
5 mg after the first 4 weeks, then increase by 2.5 mg every 4 weeks as tolerated. The label allows a lower maintenance dosage if a dose is not tolerated.
CeilingClinic-reported
15 mg once weekly (label maximum); 10 mg once weekly for pediatric Mounjaro patients 10 years and older
FrequencyClinic-reported
Once weekly
RouteClinic-reported
Subcutaneous injection
TimingClinic-reported
Once weekly at any time of day, with or without meals. The weekly day may be changed if at least 3 days (72 hours) separate the two doses. Give a missed dose within 4 days (96 hours); otherwise skip it. A fixed weekday is a practice convention, not a label requirement.
CycleClinic-reported
Continuous long-term therapy. In SURMOUNT-4, withdrawal after a 36-week lead-in led to 14.0% weight regain over 52 weeks, while continued treatment gave a further 5.5% loss.
  • Clinic-reportedProfessional education9
    If additional glycemic control is needed, increase the dosage in 2.5 mg increments after at least 4 weeks on the current dose, up to a maximum dose of 15 mg for adults.
  • Community-reportedOther web source8
    a doctor will likely increase it to 5 mg once weekly after 4 weeks.
  • Community-reportedOther web source8
    they will continue to increase your dose by 2.5 mg once every 4 weeks, up to a maximum of 15 mg once per week.
  • Community-reportedOther web source10
    The starting dose of tirzepatide is 2.5 mg for 4 weeks, then the dose is increased by 2.5 mg every 4 weeks (2.5 to 5 to 7.5 to 10 to 12.5 to 15 mg) up to 15 mg or MTD (10 mg or 15 mg)

Safety

Serious warnings

  • Boxed warning (Zepbound label): 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)].1
  • Label warnings and precautions (Section 5): severe gastrointestinal adverse reactions; acute kidney injury due to volume depletion; acute gallbladder disease; acute pancreatitis; hypersensitivity reactions; hypoglycemia; diabetic retinopathy complications in patients with type 2 diabetes mellitus; pulmonary aspiration during general anesthesia or deep sedation; never share a Zepbound KwikPen between patients. Discontinue if pancreatitis is suspected.1
  • Severe gastroparesis: Zepbound is not recommended in patients with severe gastroparesis. In pooled weight-reduction trials, severe GI adverse reactions occurred in 1.7% (5 mg), 2.5% (10 mg) and 3.1% (15 mg) versus 1% with placebo.1
  • Limitation of use: coadministration with other tirzepatide-containing products or with any GLP-1 receptor agonist is not recommended.1
  • FDA states that adverse event reports for compounded semaglutide or tirzepatide include doses beyond what is in the FDA-approved label. FDA advises providers to be vigilant when prescribing compounded semaglutide or tirzepatide and when determining appropriate doses, titration and dosing schedules.11

Contraindications

  • A personal or family history of MTC or in patients with MEN 2.1
  • Known serious hypersensitivity to tirzepatide or any of the excipients in ZEPBOUND.1

Adverse effects

  • Label Table 1, placebo versus Zepbound 5/10/15 mg: nausea 8% vs 25/29/28%; diarrhea 8% vs 19/21/23%; vomiting 2% vs 8/11/13%; constipation 5% vs 17/14/11%.1
  • SURMOUNT-1: the most common adverse events were gastrointestinal, mild to moderate, and mainly during dose escalation. Discontinuation for adverse events was 4.3% (5 mg), 7.1% (10 mg), 6.2% (15 mg) and 2.6% (placebo).3
  • SURPASS-2: nausea 17 to 22%, diarrhea 13 to 16% and vomiting 6 to 10% with tirzepatide. Hypoglycemia (<54 mg/dL) occurred in 0.6% (5 mg), 0.2% (10 mg) and 1.7% (15 mg). Serious adverse events were 5 to 7% with tirzepatide versus 3% with semaglutide.6
  • Pediatric Mounjaro patients: vomiting, abdominal pain and hypoglycemia are reported more often than in adults. The size of this difference is not established.2

Monitoring

  • Renal function: monitor renal function in patients reporting adverse reactions that could lead to volume depletion, especially during dosage initiation and escalation (5.3).1
  • Narrow-therapeutic-index and threshold-dependent oral drugs (for example warfarin): monitor when coadministered, because gastric emptying is delayed (7.2).1
  • Hypoglycemia: consider a lower insulin or sulfonylurea dose when starting (5.7, 7.1). Retinopathy progression in type 2 diabetes with prior retinopathy (5.8). Pancreatitis symptoms: discontinue if suspected (5.5). Calcitonin and thyroid ultrasound are not routine; evaluate an elevated calcitonin or a thyroid nodule (5.1). Pregnancy status (8.1).1

Interactions

  • Delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications.1
  • Consider a lower insulin or sulfonylurea dose when starting to reduce hypoglycemia risk.1
  • Advise patients using oral hormonal contraceptives to switch to a non-oral contraceptive method, or add a barrier method of contraception for 4 weeks after initiation with ZEPBOUND and for 4 weeks after each dose escalation.1
  • Do not combine with other tirzepatide-containing products or any GLP-1 receptor agonist (limitation of use). This applies when a clinic also dispenses semaglutide.1

Handling

Reconstitution

Not applicable to the approved presentations, which are supplied ready to inject (single-dose pens, single-dose vials, multi-dose vials and single-patient-use KwikPens; the multi-dose vials and KwikPen hold four doses each). Reconstitution of compounded lyophilized tirzepatide is not established. Follow the dispensing pharmacy's label.

Storage before mixing

Zepbound single-dose pen and vial: store in a refrigerator at 2°C to 8°C (36°F to 46°F); may be stored unrefrigerated at up to 30°C (86°F) for up to a total of 21 days. Storage of compounded product is set by the dispensing pharmacy and is not established.

Storage after mixing

Not established for compounded product.112

Evidence

FDA-approved as Zepbound (chronic weight management, obstructive sleep apnea) and Mounjaro (type 2 diabetes). The phase 3 trials SURMOUNT-1, SURPASS-1 and SURPASS-2 tested 5, 10 and 15 mg once weekly. The label starts at 2.5 mg for 4 weeks, moves to 5 mg, then increases in 2.5 mg steps after at least 4 weeks on the current dose, to a maximum of 15 mg. SURMOUNT-4 showed substantial weight regain after withdrawal. Compounded tirzepatide is unapproved. FDA reports adverse events at doses beyond the label.

Mechanism

Tirzepatide is a once-weekly, subcutaneously injected agonist at both the GIP and GLP-1 receptors. In trials it produced dose-dependent weight reduction and glycemic improvement in obesity and type 2 diabetes.37

Availability

Amounts offered

  • 10 mg
  • 15 mg
  • 20 mg
  • 30 mg
  • 40 mg
  • 50 mg
  • 60 mg
  • 90 mg
  • 120 mg
  • 180 mg

Custom strengths on request.

Book a call

References

According to PubMed

  1. 1ZEPBOUND (tirzepatide) injection, prescribing information (openFDA drug label record; effective_time 2026-08-28, version 40, set_id 487cd7e7-434c-4925-99fa-aa80b1cc776b; meta last_updated 2026-10-14)U.S. Food and Drug Administration via openFDA; NDA 217806, 2026
  2. 2MOUNJARO (tirzepatide) injection, prescribing information (openFDA record, repackager SPL A-S Medication Solutions, effective_time 2026-07-29; re-cite Lilly's own DailyMed SPL before publication)U.S. Food and Drug Administration via openFDA, 2026
  3. 3Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)N Engl J Med 2022;387(3):205-216, 2022
  4. 4Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical TrialJAMA 2024;331(1):38-48, 2024
  5. 5Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA)N Engl J Med 2024;391(13):1193-1205, 2024
  6. 6Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2)N Engl J Med 2021;385(6):503-515, 2021
  7. 7Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1): a double-blind, randomised, phase 3 trialLancet 2021;398(10295):143-155, 2021
  8. 8Zepbound dosing schedule, and how often to increase the dose (medically reviewed by Alyssa Walton, PharmD; last updated June 24, 2026)Medical News Today (consumer drug-information site), 2026
  9. 9How should Mounjaro (tirzepatide) doses be increased in adults? (Lilly Medical, date of last review August 28, 2026)Eli Lilly and Company, Medical Information, 2026
  10. 10A Study of Tirzepatide (LY3298176) in Participants With Obesity or Overweight With Weight Related Comorbidities (NCT05822830, SURMOUNT-5 trial protocol)ClinicalTrials.gov large document, Eli Lilly
  11. 11FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss (content current as of 10/01/2026)U.S. Food and Drug Administration, 2026
  12. 12FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products (content current as of 07/26/2024)U.S. Food and Drug Administration, 2024
  13. 13FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize (content current as of 04/01/2026)U.S. Food and Drug Administration, 2026
  14. 14Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act (content current as of 05/14/2026)U.S. Food and Drug Administration, 2026

Last reviewed 2026-10-14. 31 figures checked against their sources. How this works