Retatrutide, or reta.
What the compound is, what investigational means and why it is the most important word on this page, the vial sizes that appear on labels, the unit conversion, storage, and what tracking a retatrutide protocol looks like in Protocol Her.
- Compound class
- Triple GIP, GLP-1, and glucagon receptor agonist
- In the Protocol Her library as
- Retatrutide
- Doses entered in
- mg
- A new schedule starts at
- Once a week
- Powder vial sizes commonly seen
- 5 mg, 10 mg, 15 mg, 20 mg
The classification badge describes the molecule's regulatory status as the app's library currently records it. Regulatory status can change over time, and the badge says nothing about any individual vial or seller.
Three receptors, and no label.
Retatrutide is an engineered peptide that acts on three receptors: GIP, GLP-1, and glucagon. Where semaglutide targets one and tirzepatide two, this one targets three, which is the whole reason people talk about it. It has been studied in clinical trials and, unlike those two, has no FDA-approved product behind it.
What investigational means
There is no approved product, which means no approved label, no approved indication, and no pharmacy dispensing it as a finished medicine. The safety and effectiveness questions a full review answers are, for this compound, still open questions rather than settled ones.
What that means for supply
With no approved product, there are no pens. Everything in circulation is research-labeled powder sold outside a pharmacy supply chain, where identity, purity, and the accuracy of the printed mg all rest on the seller's own claim.
What this page will not do
It will not tell you an amount, a schedule, how much water to add, or where to buy anything, and it makes no claim about what retatrutide will do for you. Those belong with a clinician who knows your history. What follows is arithmetic and handling.
One format, one number.
Because no finished product exists, retatrutide only turns up one way: freeze-dried powder in a small glass vial with a mg total printed on it.
The numbers on labels
Labels most often read 5 mg, 10 mg, 15 mg, or 20 mg. That figure is a total mass, not a strength. Until liquid is added there is no mg/mL, no mL, and nothing a syringe can measure.
What the number is not
A printed mg total is a claim, not a verified measurement, and it is not comparable across compounds: a milligram of reta is not a milligram of tirz or sema. Same word, different molecules, different scales entirely.
Read the mg figure off the vial in front of you every time rather than assuming it matches the last one. Protocol Her deliberately ships no preset vial sizes for any compound, because the only number that is true is the one on your own label.
From mg on the label to units on the barrel.
Take a 10 mg vial with 2 mL of bacteriostatic water added, and say you want to measure 3 mg. Every number here was picked to make the arithmetic easy to follow. None of them is a suggested vial size, water volume, or amount.
Concentration
Divide the peptide in the vial by the water you added. That is the strength of every mL in the finished solution.
10 mg ÷ 2 mL = 5 mg/mL
Volume
Divide the amount you want by the concentration. That gives the volume of liquid holding it. Retatrutide is entered in mg, so no unit conversion is needed first.
3 mg ÷ 5 mg/mL = 0.6 mL
Syringe units
A U-100 insulin syringe is marked at 100 units per mL, so multiply by 100 to read the same volume on the barrel.
0.6 mL × 100 = 60 units
Change nothing but the water and the reading moves: 10 mg in 1 mL is 10 mg/mL, and that same 3 mg becomes 0.3 mL, or 30 units. Half the marks on the barrel for exactly the same amount of peptide. This is why the concentration has to be recalculated for every new vial rather than carried over by habit.
Run your own numbers in the free calculatorPeptides are fragile proteins.
Heat, light, and agitation are what degrade them. General handling principles below. Note that an investigational compound has no manufacturer storage label to fall back on, which is its own kind of unknown.
- Before mixing, the powder is the stable form. Freeze-dried peptide keeps far better than solution. Store it away from light and heat.
- Once liquid is added, it is refrigerated. Reconstituted peptide belongs in the fridge, upright, not in the door where the temperature swings every time it opens.
- Do not freeze a reconstituted vial. Ice crystals damage peptide in solution. Freezing and rethawing is not a way to extend anything.
- Add water gently and do not shake. Run the stream down the inside wall of the vial and swirl slowly. Foaming means agitation, and agitation denatures protein.
- Bacteriostatic water is not sterile water. Bacteriostatic water contains a preservative, benzyl alcohol, which is what allows a vial to be entered more than once. Sterile water has none. They are not interchangeable.
- Write the date you mixed it on the vial. A date on the label beats memory. Discard a vial that is cloudy, discolored, or has anything floating in it.
- No approved label means no verified stability data. Any storage window quoted for an investigational compound is convention or a seller's claim, not information from a regulatory review.
Protocol Her records the date you reconstituted a vial and seeds a discard date 28 days later, a common convention rather than an expiry the app is asserting. The date is yours to change, and the app never claims a beyond-use date on your behalf.
Tracking a reta protocol, exactly as it ships.
Retatrutide is one of 35 compounds in the app's library. Picking it sets up the frame: the category, the classification, the unit your doses are entered in, and a starting cadence. Every number stays yours to enter.
A warning that never hides
Retatrutide carries the app's standing investigational card: not FDA-approved, not for use in pregnancy, and it may lower the effectiveness of oral birth control. It shows whenever the compound is selected, never triggered by a number you typed.
A schedule you set
A new retatrutide schedule opens on Once a week, because weekly is intrinsic to how this compound is studied. You can move it to every day, every other day, twice a week, every 2 weeks, or as needed, then pin a weekday and a time.
Doses in mg, with the site
Each logged dose carries the amount in mg, the time, and one of seven injection sites: left or right abdomen, thigh, or arm, plus glute. The body map remembers where the last ones went, so rotating stops being a memory game.
The vial, tracked
Log the mg and the water you added and the app carries the concentration forward: doses remaining, a low-stock signal, cost per dose, and the reconstitution and discard dates. The same conversion runs on a live U-100 syringe gauge.
Metabolic check-ins
Because retatrutide sits in the Metabolic category, the daily card offers weight, energy, hunger, protein, and body measurements. Side effects log with a 1 to 5 severity, which matters more, not less, for a compound without an approved label.
A record you can hand over
Log your period and doses and symptoms gain cycle-phase context. Weeks on the protocol are counted from what you logged, never prescribed ahead of you, and the history exports as a clinician-ready PDF.
All of it stays on your iPhone. There is no account and no server copy of what you log, and reminders never name a compound or an amount on your lock screen. Note one deliberate absence: the app shows no reference range for retatrutide unless one is traceable to a published human trial, and it ships no dose ladder, no vial presets, and no water volumes.
Common questions, answered.
What does reta mean?
Reta is everyday shorthand for retatrutide, the same kind of contraction as sema and tirz. It is not a separate compound, a brand, or a different strength.
Why is it labeled investigational?
Because it has been studied in clinical trials but has no FDA-approved product behind it, unlike sema and tirz. The app shows that classification on the compound at all times, with a standing warning card, never gated behind a value you entered.
How do I turn mg into syringe units?
Divide vial mg by the mL of water added for the concentration, divide your amount by that concentration for a volume in mL, then multiply by 100 for a U-100 syringe. The free calculator runs the same chain and prints every step.
Can I compare reta mg to tirz mg?
No. A milligram is a unit of mass, not of effect, and these are different molecules acting on different numbers of receptors. Reading across compounds by the number on the label is one of the easier ways to get the arithmetic right and the meaning badly wrong.
The rest of the library.
Track it where it stays yours.
Protocol Her keeps doses, vials, symptoms, cycle, and labs in one place, with the reconstitution calculator and a live U-100 syringe gauge built in. Free to download, no account to create.
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