Tirzepatide is a dual agonist acting at both the GIP and GLP-1 receptors. It is approved in multiple jurisdictions for type 2 diabetes and chronic weight management, and is given as a weekly subcutaneous injection. Published pharmacokinetics describe a half-life of approximately five days.
By Tessaro Pty Ltd, the maker of Pepti · Last reviewed
This page is a reference, not a protocol. It sets out what the published trials actually report, what a five-day half-life means for a weekly record, and what a clean log holds. It contains no dose figures and no schedule, and the section further down explains why that is deliberate rather than an omission.
| Property | Value |
|---|---|
| Mechanism | Dual agonist — GIP and GLP-1 receptors |
| Status | Approved in multiple jurisdictions for type 2 diabetes and chronic weight management; also widely used in compounded form |
| Route and cadence | Subcutaneous injection, once weekly |
| Half-life | Approximately 5 days (about 120 hours) — per published pharmacokinetics, and the value Pepti stores |
| Product form | Approved-product pens are prefilled solution; compounded vials are commonly supplied as lyophilized powder requiring reconstitution |
Published data describe a mean body-weight reduction of 20.9 percent at 72 weeks (Jastreboff et al., NEJM 2022). That result is what moved the expectation for the class upward, and it is the figure most later comparisons are anchored to.
The more useful result came later, because it is the only direct head-to-head comparison in this class. Aronne et al., NEJM 2025 report that tirzepatide produced greater mean body-weight reduction than semaglutide in a randomized comparison of the two agents, approximately 20.2 percent against 13.7 percent at 72 weeks. That distinction matters more than it may appear. The percentages our other pages line up side by side, including investigational retatrutide at 24.2 percent over 48 weeks (Jastreboff et al., NEJM 2023), come from separate trials with different populations, durations and designs, and carry an explicit caveat that they are not comparable. This one does not need that caveat: the two agents were compared in the same trial, in the same population, over the same period.
The figure that matters most to a record, though, is not an efficacy number at all. Published data describe one-year persistence on GLP-1 therapy of 64.8 percent (Rodriguez et al., JAMA Network Open 2025), meaning roughly one in three people stop within a year. Whatever drives that in an individual case, it makes the dated history unusually valuable: when the conversation with whoever directs your use turns to whether to continue, a complete record of what was taken, when, and what was observed alongside it is the only evidence in the room that is actually about you.
A half-life is the time taken for half of what is present to clear. At approximately five days, weekly injections still overlap rather than clearing between them, so levels build across the early weeks instead of returning to zero. The overlap is smaller than it is for a seven-day compound, which makes the timing of each injection somewhat more visible in how the week feels.
Two things follow for record-keeping. A missed week is a much larger gap than a missed day would be on a daily compound, so the log needs to make an absent week obvious at a glance rather than burying it. And because the curve is slow, what you notice in any given week is a product of several preceding weeks, not just the most recent injection, which makes the dated history far more informative than any single entry in it.
Tirzepatide is an approved product with an official label, and that label is where approved-product dosing lives. It is a matter between you and whoever directs your use. Restating label figures on a tracking site adds nothing and risks a good deal, because a number copied out of context loses the conditions attached to it.
Compounded tirzepatide is a different situation again. Concentration varies from preparation to preparation, so a figure that was correct for one vial can be wrong for the next one, and no page can tell you what is in the vial in front of you. That is precisely why Pepti computes a draw volume from the figures you already have rather than suggesting any of its own. The measurement is ours; the figure is not, and it never will be.
Because the cadence is weekly, there are relatively few entries in a tirzepatide log, which makes each one carry more weight. A record worth keeping holds the following.
The reconstitution calculator converts the figures you already have into a draw volume and a count of doses per vial, the injection site rotation guide sets out the zone system, and how to track peptide cycles covers the record-keeping method in full.
Tirzepatide is a dual agonist: it acts at both the GIP and the GLP-1 receptor, where earlier agents in the class act at GLP-1 alone. The practical consequence is effects on appetite signalling, gastric emptying and glucose-dependent insulin secretion through two incretin pathways rather than one. It is given as a weekly subcutaneous injection.
Yes. Tirzepatide is approved in multiple jurisdictions for type 2 diabetes and for chronic weight management, which means an official label exists and the dosing in it is a matter for whoever directs your use. It is also widely used in compounded form, which is not the approved product and is not covered by that label.
Approximately five days, about 120 hours, per published pharmacokinetics. That is the value Pepti uses when it draws reference curves. A half-life of this length is why the cadence is weekly: successive injections overlap rather than clearing between administrations, so levels build across the early weeks instead of returning to zero each time.
In the one direct randomized comparison published to date, yes. Aronne et al., NEJM 2025 report tirzepatide produced greater mean body-weight reduction than semaglutide, approximately 20.2 percent against 13.7 percent at 72 weeks. Two caveats matter. That is a mean across one trial population, and individual response varies widely, so a group average does not predict any one person's result. Effectiveness is also only one input into a decision that belongs to you and whoever directs your use.
It depends on the form in front of you. The approved product is supplied ready to use as a solution and requires no mixing. Compounded material is commonly supplied as a lyophilized powder, which is inert until a diluent is added, and its concentration varies between preparations rather than being fixed. These are different physical products, and a record that does not say which one it describes is ambiguous later.
No. Pepti supplies no dose figures for tirzepatide or for anything else. It records the figure you already have from whoever directs your use, converts it into a draw volume and syringe units, tracks what is left in each vial, and keeps the site sequence. The arithmetic is ours; the figure is not.
This page is a reference on published evidence and record-keeping. It does not recommend tirzepatide or any other substance, and it provides no dose figure, no titration amount, and no schedule. Approved-product dosing is a matter for the official label and for whoever directs your use.
Track it all in Pepti — the weekly log, the site sequence, the vial count and the weight trend, kept in one place.
Not medical advice. Pepti is a record-keeping and measurement tool, not a medical device.
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