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Retatrutide dose calculator

Convert any Retatrutide dose into syringe units in real time, pre-filled with a 10 mg / 2 mL example.

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Draw on a U-100 syringe

40.0 units

Volume to draw

0.400 mL

Retatrutide is an experimental once-a-week injection people are tracking for weight loss and blood-sugar effects. It's the first triple agonist — it hits GLP-1, GIP, and glucagon receptors together, which appears to amplify both appetite suppression and energy expenditure. In a Phase 2 trial, adults with obesity lost about 24.2% of body weight at 48 weeks on the highest dose. It is still investigational and not approved. This page covers the reconstitution math and weekly logging cadence.

How the Retatrutide dose calculator works

This calculator answers a simple question: given the concentration of the Retatrutide solution already in your vial, how many syringe units does today's dose work out to? It is the second half of the reconstitution math — the first half locks in concentration, this one converts any dose mg or mcg into a clean unit count.

The formula is volume in mL equals dose mg divided by concentration mg/mL, then volume times one hundred to get units on a U-100 insulin syringe. With a 5 mg/mL Retatrutide solution and a 2 mg dose, the draw is 0.40 mL or about 40 units. Type any other dose and the unit count updates in real time — no spreadsheets, no guesswork.

Inputs that genuinely matter: concentration (which only changes when you reconstitute a new vial) and dose mass. Syringe type matters too, but only because U-100 vs U-40 changes the multiplier — almost every modern insulin syringe is U-100, which is why the math defaults to that. Edge cases worth flagging: switching from mcg to mg without checking the input unit, or carrying yesterday's unit count over to a new vial that was reconstituted with a different volume of BAC water.

Most people use this calculator at two moments: when titrating a dose up or down, and when prepping a single dose before injection. The output is meant to be checked against the syringe before drawing — read the markings, confirm the unit count, then draw. The calculator is fast precisely so you can do that check every time without it feeling like a chore.

How Retatrutide dosing is tracked

Once-weekly subcutaneous injection is the default cadence in most retatrutide logs. Each draw is small enough that a U-100 insulin syringe is the standard tool — the volumes involved are too small to read accurately on a tuberculin syringe.

Because retatrutide is potent at small milligram counts, dose escalation tends to be gradual and well-tracked. The exact week and unit count of each step is the kind of information that is hard to reconstruct from memory months later, which is why a structured dose log is more durable than scattered notes.

Dosing schedules documented in published Phase 2 clinical trials for retatrutide have involved a notably steep titration. Study protocols have detailed starting doses that escalate at predetermined intervals to much higher terminal doses than those typical for related peptides. For example, a documented titration schedule involved monthly escalations from a starting dose, progressing through tiers such as 2 mg, 4 mg, 8 mg, and up to a 12 mg maximum dose, all administered on a weekly cadence. For personal tracking, these published trial schedules are the only available structural reference points for logging dose escalation over a period of months.

Retatrutide mechanism in plain English

Retatrutide binds to the GIP, GLP-1, and glucagon receptors. The first two are familiar from semaglutide and tirzepatide; the addition of glucagon-receptor activation is what differentiates retatrutide from those earlier peptides and is the focus of much of its ongoing clinical research.

Triple-receptor activation produces metabolic effects that are still being characterized in published trials. Anyone tracking retatrutide in a personal log should pair the dose history with weekly metrics like weight, hunger ratings, and side-effect notes — that pairing is what turns a list of injections into a usable trend.

The compound's pharmacology is defined by its activity as a single-molecule agonist for the glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG) receptors. While co-activation of GLP-1 and GIP receptors is also the mechanism of tirzepatide, the addition of the glucagon receptor agonist component is what makes retatrutide a distinct investigational agent. In metabolic physiology, glucagon signaling is traditionally associated with stimulating the liver to produce glucose. However, researchers are studying how its concurrent activation with potent incretin mimetics like GLP-1 and GIP might influence energy expenditure, lipid metabolism, and appetite signaling in ways that are distinct from single- or dual-agonist peptides.

Common Retatrutide dose mistakes

  • Reusing a unit count from a previous vial without re-checking the new vial's diluent volume.
  • Confusing retatrutide doses with semaglutide or tirzepatide doses — the milligram ranges differ and the math does not transfer.
  • Skipping the escalation date in the log, then losing the timeline of when each step actually occurred.
  • Letting reconstituted retatrutide warm to room temperature for extended periods on travel days.
  • Not writing the reconstitution date on the vial itself — the in-use window is long enough that an unmarked vial becomes ambiguous.
  • Assuming retatrutide has established prescribing information and failing to recognize its investigational-only status.
  • Neglecting to calculate injection volume for high-end doses, leading to logistical issues with standard 1 mL syringes.
  • Incorrectly logging it as a dual-agonist peptide, confusing its unique triple-receptor mechanism with that of tirzepatide.

Frequently asked questions about Retatrutide dose

How is retatrutide reconstituted?
By drawing a measured volume of bacteriostatic water into a syringe and injecting it slowly into the lyophilized vial through the rubber stopper, then swirling — not shaking — until the powder fully dissolves into a clear solution.
How many units of retatrutide are in 2 mg?
It depends on the concentration of your vial. On a 10 mg vial reconstituted with 2 mL of bacteriostatic water (5 mg per mL), 2 mg is exactly 40 units on a U-100 syringe.
Is retatrutide approved as a pharmaceutical?
Not at the time of writing. Retatrutide is investigational and is currently being studied in pharmaceutical clinical trials. Anything beyond that — including dosing decisions — is a conversation for a licensed healthcare professional, not for a calculator page.
How long does a 10 mg vial of retatrutide last?
At a 2 mg weekly dose, a 10 mg vial provides 5 doses, or 5 weeks of supply. The vial duration calculator runs the math for any combination of vial size, dose, and frequency.
Why does retatrutide get tracked the same way as semaglutide?
Because the underlying logging shape is the same: weekly long-acting peptide, lyophilized vial, gradual dose escalation, paired weekly metrics. The math, the vial workflow, and the refill cadence are all structurally identical even though the molecule is different.
Does retatrutide need to be refrigerated?
Lyophilized powder is typically stored refrigerated, and the reconstituted vial is kept refrigerated and used within several weeks. Repeated temperature cycling reduces stability, so storing the vial in the door of the refrigerator is best avoided.
How does retatrutide's mechanism differ from semaglutide's mechanism?
The primary difference is the number of hormone receptors they target. Semaglutide is a single agonist, designed to activate only the glucagon-like peptide-1 (GLP-1) receptor. Retatrutide is a triple agonist, engineered to concurrently activate the GLP-1 receptor, the GIP receptor, and the glucagon receptor.
How does retatrutide's mechanism differ from tirzepatide's mechanism?
The key distinction is the addition of a third target receptor. Tirzepatide is a dual agonist that activates both the GLP-1 and GIP receptors. Retatrutide expands on this by also activating the glucagon receptor, making it a triple-agonist compound. The glucagon receptor activation is the novel component not present in tirzepatide.
Why are the doses logged for retatrutide different from other peptides?
Retatrutide is an investigational compound without any approved dosing guidelines. The doses that are tracked and logged are based on data from published clinical trials. These studies have explored specific, escalating dose schedules that reach higher magnitudes, such as 8 mg or 12 mg per week, than the typical terminal doses for commercially available GLP-1 agonists.

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