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Tirzepatide (Mounjaro/Zepbound)

Peptideprescriptionsubcutaneous · inferred

Dual GIP/GLP-1 receptor agonist approved for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound). Half-life of ~5 days (120 h) supports once-weekly dosing. Uniquely activates both GIP and GLP-1 receptors, producing robust weight loss and glycemic improvement.

Projected serum levels — 5 mg, weekly

Tirzepatide (Mounjaro/Zepbound)
Tirzepatide (Mounjaro/Zepbound) modeled serum levels, 5 mg weekly over 42 days Population-based pharmacokinetic estimate. Steady state reached after approximately 14 days. 0 1.3 2.5 3.8 5 Day 0 Day 11 Day 21 Day 32 Day 42 Time on a regular schedule ≈ steady state · day 14
Tirzepatide (Mounjaro/Zepbound) modeled serum levels with a loading dose of 8.6 mg, then 5 mg weekly The first dose is larger so levels approach steady state faster. 0 1.3 2.5 3.8 5 Day 0 Day 11 Day 21 Day 32 Day 42 Time on a regular schedule

Maintenance schedule: 5 mg weekly (subcutaneous).

Loading schedule: 8.6 mg on day 1, then 5 mg weekly — reaching therapeutic levels sooner.

Modeled steady state after ~14 days: peak ≈ 3.7 mg, trough ≈ 2.1 mg body load. Population-based estimate over 42 days for a 5 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Peptide
Route modeled
Subcutaneous
Model confidence
inferred
Half-life
5 days
Common dose
5 mg
Suggested maximum
15 mg/day
Reference dose range
2.5–15 mg (single dose)
Suggested cadence
weekly
Validated against
15 mg sc — Cmax 0.80 mg/L at 36 h

Documented interactions

  • moderate
    Retatrutide (Reta) + Tirzepatide (Mounjaro/Zepbound) Stacked effects

    Retatrutide (Reta) and Tirzepatide (Mounjaro/Zepbound) both push the gip receptor and glp1 receptor in the same direction.

  • watch
    Dulaglutide (Trulicity) + Tirzepatide (Mounjaro/Zepbound) Stacked effects

    Dulaglutide (Trulicity) and Tirzepatide (Mounjaro/Zepbound) both push the glp1 receptor in the same direction.

  • watch
    Liraglutide (Victoza/Saxenda) + Tirzepatide (Mounjaro/Zepbound) Stacked effects

    Liraglutide (Victoza/Saxenda) and Tirzepatide (Mounjaro/Zepbound) both push the glp1 receptor in the same direction.

  • watch
    Semaglutide (Ozempic/Wegovy) + Tirzepatide (Mounjaro/Zepbound) Stacked effects

    Semaglutide (Ozempic/Wegovy) and Tirzepatide (Mounjaro/Zepbound) both push the glp1 receptor in the same direction.

  • watch
    Sitagliptin (Januvia) + Tirzepatide (Mounjaro/Zepbound) Stacked effects

    Sitagliptin (Januvia) and Tirzepatide (Mounjaro/Zepbound) both push the glp1 receptor in the same direction.

Serum checks 5 modeled interaction pairings for tirzepatide (mounjaro/zepbound) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1) Jastreboff AM et al. · New England Journal of Medicine, 2022 DOI

    Pivotal trial showing tirzepatide 15 mg weekly produced 22.5% mean body weight reduction at 72 weeks in adults with obesity, the largest weight loss from any drug at the time.

  2. Population pharmacokinetics of the GIP/GLP receptor agonist tirzepatide Schneck KB et al. · CPT: Pharmacometrics & Systems Pharmacology, 2024 DOI

    Population PK model from 19 pooled studies establishing tirzepatide half-life of ~5 days with two-compartment first-order absorption/elimination, supporting once-weekly dosing without adjustment for demographics.

  3. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2) Frias JP et al. · New England Journal of Medicine, 2021 DOI

    Head-to-head trial demonstrating tirzepatide was superior to semaglutide 1 mg in reducing HbA1c and body weight in patients with type 2 diabetes over 40 weeks.

3 published studies referenced in the app, each with a plain-language summary.