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Protocol Reference
Human trial data

Tirzepatide protocol

Tirzepatide (GIP / GLP-1 dual agonist). Dosing on this page comes from a published human trial or an approved product label, cited below.

PepGuru Research Team·Reviewed Aug 2026
Category
GLP-1 & Metabolic
Common vials
10, 20, 30, 60, 100, 120 mg
Half-life
~5 days
Route in the literature
Subcutaneous, once weekly
Evidence level
Human trial data

How Tirzepatide works

A single peptide that activates both the GIP and GLP-1 receptors. That dual mechanism is what separates it from semaglutide and is the leading explanation for the larger weight changes in head-to-head work.

Tirzepatide dosing schedule

From the SURMOUNT-1 phase 3 obesity trial and the approved label, escalating in 2.5 mg steps at four-week intervals.

PhaseAmountFrequencyNotes
Weeks 1–42.5 mgOnce weeklyLead-in step for tolerability.
Weeks 5–85 mgOnce weeklyLowest of the three maintenance arms.
Weeks 9–127.5 mgOnce weeklyEscalation step only.
Weeks 13–1610 mgOnce weeklySecond maintenance arm.
Weeks 17–2012.5 mgOnce weeklyEscalation step only.
Week 21 onward15 mgOnce weeklyHighest maintenance arm.

Study length: 72 weeks in SURMOUNT-1. Arms stopped escalating at 5, 10 or 15 mg.

Source for this schedule: Jastreboff AM et al., "Tirzepatide Once Weekly for the Treatment of Obesity", NEJM 2022 (SURMOUNT-1). This reproduces what was administered in that work. It is reference information about a study, not a recommendation, and the trial population, monitoring and endpoints are part of what made it a protocol.

Reconstitution and measurement

This part is arithmetic and does not depend on the evidence level. Concentration is vial size divided by the bacteriostatic water you add. Draw volume is your target amount divided by that concentration. Units are draw volume times 100, because a U-100 syringe reads 100 units per millilitre. Common vials for Tirzepatide: 10, 20, 30, 60, 100, 120 mg.

Open the Tirzepatide calculator → Unit converter

Storage and stability

Dry powder
Cold, dark and dry. Lyophilized peptide is the stable form — keep it that way until you intend to use it.
After reconstitution
Refrigerate at 2–8 °C, protect from light, and plan around a limited window. Do not freeze a reconstituted vial — freeze-thaw damages peptides.
Mixing
Run bacteriostatic water down the inside wall of the vial rather than onto the powder, then swirl. Never shake.
Inspect before use
A clear solution is expected. Cloudiness or particles mean discard, not use.

Full storage guide → · Cloudy solution?

Reported effects

  • Gastrointestinal effects dominated the adverse-event profile and were concentrated during escalation.
  • Discontinuation for adverse events rose with the higher arms.
  • Same class-wide rodent thyroid C-cell finding as other incretin agonists.

Sourcing Tirzepatide

Whatever you are working with, the documentation matters more than the price. Ask for a batch certificate of analysis whose lot number matches the vial you actually receive — a COA for a different batch tells you nothing about yours.

Tirzepatide at Summit Research Supply → Grade a COA first

Summit is the supplier we feature and an affiliate link. Our COA checklist applies the same way to any vendor.

For laboratory research use only. This page documents what the published literature reports about Tirzepatide. It is not a recommendation, not a treatment plan, and not medical advice. Compounds referenced are sold strictly as research chemicals and are not for human or veterinary use. Some supplier links are affiliate links and may earn us a commission. This never affects tier placement or review conclusions.
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