Retatrutide 10mg is a lyophilized vial of LY3437943, CAS 2381089-83-2. Ten milligrams is approximately 2.04 micromoles using the higher of the two circulating molecular weights, and the reconstitution arithmetic below assumes that figure.
Specification Table
Retatrutide verified data, 10mg format
| Property |
Value |
| Compound |
Retatrutide |
| Development code |
LY3437943 |
| CAS number |
2381089-83-2 |
| Vial content |
10 mg lyophilized powder |
| Molar content at MW 4894.58 |
Approximately 2.04 µmol |
| Molar content at MW 4731.33 |
Approximately 2.11 µmol |
| Molecular formula |
C228H350N48O66 |
| Molecular weight |
Contested. 4894.58 and 4731.33 both circulate. See the note on the 5mg page |
| Residue count |
39 |
| C-terminus |
Amidated |
| Peptide backbone |
Based on the GIP sequence rather than GLP-1 |
| Non-coded residue, position 2 |
α-aminoisobutyric acid (Aib) |
| Non-coded residue, position 13 |
α-methyl-leucine |
| Non-coded residue, position 20 |
α-aminoisobutyric acid (Aib) |
| Lipid conjugation |
Lysine 17 side chain bears PEG2-γ-Glu-eicosanedioic acid |
| Molecular targets |
GIP receptor, GLP-1 receptor, glucagon receptor |
| Reported EC50, GIPR |
0.0643 nM |
| Reported EC50, GLP-1R |
0.775 nM |
| Reported EC50, GCGR |
5.79 nM |
| Originating organisation |
Eli Lilly |
| Appearance |
White lyophilized powder |
| Purity |
Per lot-specific certificate of analysis |
| Solubility |
Water soluble. Slightly alkaline buffer aids dissolution |
| Storage, lyophilized |
-20°C, protected from light and moisture |
| Storage, reconstituted |
2-8°C, protected from light |
| Regulatory status |
Investigational. No approved formulation in any jurisdiction |
How Should Retatrutide Reconstitution Be Approached?
Retatrutide 10mg arithmetic carries an unusual wrinkle because the molecular weight is contested, so the same mass gives two different molar answers depending on which figure is used.
Retatrutide 10mg divided by 4894.58 gives approximately 2.04 micromoles. Divided by 4731.33 it gives approximately 2.11 micromoles. The gap is about 3.4 percent and it propagates into every downstream concentration.
Reconstituted into 2 ml the vial yields roughly 1.02 mM on the first figure or 1.06 mM on the second. Into 5 ml, roughly 0.41 mM or 0.42 mM. Choose the volume against the working range before opening rather than after.
Bacteriostatic water is the conventional diluent where a preparation will be drawn from repeatedly, since the benzyl alcohol suppresses microbial growth. Sterile water suits a single-use preparation. Neither choice affects the peptide chemistry appreciably at these concentrations.
Add diluent slowly down the vial wall and allow the cake to dissolve without agitation. A 39-residue peptide with helical character and a lipid tail can be driven to aggregate by vigorous shaking, and aggregation here is not reversible.
Slightly alkaline conditions aid dissolution, since the sequence carries several acidic residues and dissolves more readily above its isoelectric point.
What Does Engaging Three Receptors Mean?
The term triple agonist is used loosely in marketing and precisely in the literature, and the precise version is more interesting.
Retatrutide binds and activates three distinct receptors: the GIP receptor, the GLP-1 receptor and the glucagon receptor. All three are class B G protein-coupled receptors and all three couple predominantly to Gs, raising cyclic AMP.
Reported potency differs across them by roughly two orders of magnitude. Published EC50 values are 0.0643 nM at GIPR, 0.775 nM at GLP-1R and 5.79 nM at GCGR.
That spread matters experimentally. At a concentration near the GIPR EC50 the molecule is engaging essentially one receptor. At a concentration near the GCGR EC50 it is engaging all three, with the first two close to saturated.
A single-concentration experiment therefore cannot be described as testing triple agonism. Which receptors are actually engaged is a function of the concentration chosen, and reporting that concentration alongside the EC50 values is what makes a result interpretable.
Because all three couple to Gs, a cyclic AMP readout in a system expressing more than one of them measures a sum. Separating the contributions requires receptor-selective antagonists or genetic knockout, not careful measurement.
What Concentrations Should a Design Cover?
For Retatrutide 10mg work the EC50 spread gives an unusually clear basis for choosing a range, which is a luxury most compounds in this catalogue do not offer.
A range spanning 0.01 nM to 100 nM covers all three receptors from below the most potent EC50 to well above the least potent. Within that band the relative engagement shifts continuously, and the shape of the response curve carries mechanistic information.
A biphasic or multiphasic curve across that range is itself evidence of multiple receptor engagement. A single sigmoid suggests one receptor dominates the readout in that system.
Working above 100 nM buys little and risks off-target engagement of related class B receptors, given the sequence homology across that family.
From a 10mg vial reconstituted to roughly 1 mM, reaching 0.01 nM requires a hundred-thousand-fold dilution. Serial dilution across that span compounds error at every stage, so an intermediate stock prepared volumetrically is worth the extra step.
Where Should Retatrutide Research Material Be Sourced?
For Retatrutide 10mg, a compound under active clinical development by a named manufacturer, the gap between research-grade and clinical material is entirely documentation and manufacturing standard.
Ask what the stated purity was measured against and by which method. A percentage with no method attached carries less information than it appears to.
Ask for the measured mass rather than a catalogue figure, given the molecular weight discrepancy described on the 5mg page. A supplier quoting a number from a listing may not have measured the material in front of them.
Ask for confirmation of the three non-coded residues. Aib at positions 2 and 20 and alpha-methyl-leucine at position 13 are the modifications a shortcut synthesis would omit, and omitting them produces a peptide of correct length with materially different protease resistance.
Ask for confirmation of the lysine 17 conjugation. A preparation missing the fatty acid assembly weighs substantially less and behaves entirely differently, and it is the single most consequential thing that can be wrong with this molecule.
A supplier who can answer all four is worth more than a lower price against an unverifiable listing.
How Should Receptor Selectivity Be Demonstrated?
Claiming an effect runs through one of three receptors requires more than showing the compound is present, and the tools differ in how much they prove.
Receptor-selective antagonists are the fastest route and the weakest. Selectivity across class B receptors is imperfect, and an antagonist that partially blocks two receptors cannot cleanly attribute an effect to one.
Genetic knockout or knockdown is stronger. An effect that survives in cells lacking a receptor is not mediated by it, and that inference holds regardless of pharmacological cross-reactivity.
Heterologous expression of a single receptor in a null background is the cleanest of the three, because it removes the other two from the system entirely rather than trying to silence them.
Whichever is used, reporting the concentration alongside the published EC50 values lets a reader work out which receptors were plausibly engaged before reading the conclusion.
What Does Retatrutide 10mg Support Experimentally?
Two micromoles of a compound with sub-nanomolar potency goes a very long way, and the practical limit is rarely the vial.
At an EC50 of 0.0643 nanomolar for the most potent receptor, a full concentration-response series spanning four orders of magnitude consumes a vanishingly small fraction of Retatrutide 10mg. Even in triplicate with three receptor arms, the material is not the constraint.
What does consume it is the control burden. Receptor-selective antagonist arms, a knockout comparison and a vehicle series together multiply the well count several times over.
Adsorptive loss accounts for a further share that is easy to overlook. A lipidated peptide at picomolar working concentrations can lose a substantial proportion to container surfaces before it ever reaches a cell.
Work in plasma or serum consumes more again, because albumin binding is part of this molecule design rather than an artefact, and the free fraction in a protein-containing matrix is much lower than the nominal concentration suggests.
How Should the Reconstituted Vial Be Handled?
Once in solution Retatrutide 10mg is on a clock, and the handling sequence is the standard one applied with a little more care than usual.
Aliquot immediately after reconstitution into single-use volumes, freeze the aliquots, and thaw each one once. Repeated freeze-thaw drives aggregation in a lipidated peptide more readily than in a plain sequence.
Use low-binding consumables at working concentrations. The lipid conjugation makes this molecule surface-active, so adsorptive loss at low concentration is larger than the sequence alone would predict.
A carrier protein such as bovine serum albumin reduces that loss substantially where the downstream assay tolerates it. Note that albumin is also the molecule the lipid tail associates with in vivo, so adding it changes the free fraction as well as the recovery.
Inspect solutions for clarity before use. Cloudiness or visible particulate indicates aggregation, and aggregated material has lost the conformation the receptors recognise.
A closing note on comparability. If a programme switches between the 5mg and 10mg formats, nothing changes chemically, but the molecular weight figure used for calculation should be held constant across the whole series.
Two people in the same laboratory using 4894.58 and 4731.33 respectively will produce results that differ by 3.4 percent for no reason anyone will be able to find later. Fix the figure, write it into the method, and move on.
One further practical note concerns albumin in the assay medium. Because the lipid conjugation is designed to bind albumin, adding serum changes the free concentration substantially rather than marginally.
A result obtained in ten percent serum and a result obtained serum-free are not comparable for this molecule without measuring the free fraction, and that difference is larger here than for an unconjugated peptide.
Reporting the serum condition is therefore not a formality on this compound. It is part of the concentration.
Published Literature
References verified against the publisher record. The receptor potency figures quoted above come from the primary characterisation rather than secondary summaries.
- Coskun T, Urva S, Roell WC, Qu H, Loghin C, Moyers JS, O’Farrell LS, Briere DA, Sloop KW, Thomas MK, Pirro V, Wainscott DB, Willard FS, Abernathy M, Morford L, Du Y, Benson C, Gimeno RE, Haupt A, Coskun T. Cell Metabolism. 2022;34(9):1234-1247.
- Urva S, Coskun T, Neff LM, Yeo KP, Loghin C, Ma X, Landry J, Bray R, Milicevic Z, Haupt A. The Lancet. 2022;400(10366):1869-1881.
- Jastreboff AM, Kaplan LM, Frias JP, Wu Q, Du Y, Gurbuz S, Coskun T, Haupt A, Milicevic Z, Hartman ML. New England Journal of Medicine. 2023;389(6):514-526.
- Willard FS, Douros JD, Gabe MB, Showalter AD, Wainscott DB, Suter TM, Capozzi ME, van der Velden WJ, Stutsman C, Cardona GR, et al. JCI Insight. 2020;5(17):e140532.
- Finan B, Yang B, Ottaway N, Smiley DL, Ma T, Clemmensen C, Chabenne J, Zhang L, Habegger KM, Fischer K, et al. Nature Medicine. 2015;21(1):27-36.
Frequently Asked Questions
What is Retatrutide 10mg?
A lyophilized vial of LY3437943, CAS 2381089-83-2. Ten milligrams is approximately 2.04 micromoles using the higher circulating molecular weight, or 2.11 using the lower. Laboratory research use only.
How much does the weight discrepancy affect reconstitution?
About 3.4 percent, and it propagates into every downstream concentration. Ten milligrams in 2 ml gives roughly 1.02 millimolar on one figure and 1.06 on the other, so the calculation basis should be recorded.
Which diluent should be used?
Bacteriostatic water where the preparation will be drawn from repeatedly, since benzyl alcohol suppresses microbial growth. Sterile water suits single use. Neither affects the peptide chemistry appreciably at these concentrations.
Why avoid agitation during dissolution?
Because a 39-residue peptide with helical character and a lipid tail can be driven to aggregate by shaking, and aggregation here is not reversible. Add diluent down the wall and let the cake dissolve.
What does triple agonist mean precisely?
That the molecule binds and activates the GIP receptor, the GLP-1 receptor and the glucagon receptor. All three are class B G protein-coupled receptors coupling predominantly to Gs and raising cyclic AMP.
How different are the potencies?
By roughly two orders of magnitude. Published EC50 values are 0.0643 nanomolar at GIPR, 0.775 at GLP-1R and 5.79 at GCGR, so which receptors are engaged depends entirely on the concentration used.
Can a single concentration test triple agonism?
No. Near the GIPR EC50 the molecule engages essentially one receptor. Near the GCGR EC50 it engages all three with the first two close to saturated. Reporting the concentration alongside the EC50 values is what makes a result interpretable.
Why can a cyclic AMP readout not separate them?
Because all three receptors couple to Gs, so the signal is a sum. Separating contributions requires receptor-selective antagonists or genetic knockout rather than more careful measurement.
What concentration range is appropriate?
Roughly 0.01 to 100 nanomolar, which spans from below the most potent EC50 to well above the least potent. A multiphasic curve across that range is itself evidence of multiple receptor engagement.
What should be confirmed on the certificate?
Measured mass rather than a catalogue figure, the three non-coded residues at positions 2, 13 and 20, and the lysine 17 lipid conjugation. A preparation missing that conjugation weighs substantially less and behaves entirely differently.
Why do low-binding consumables matter here?
The lipid conjugation makes the molecule surface-active, so adsorptive loss at low working concentrations is larger than the peptide sequence alone would predict. A carrier protein reduces it where the assay tolerates one.
Compliance Statement
Retatrutide 10mg is sold exclusively for laboratory research use. It is not a drug, food, or cosmetic product, and it is not a dietary product of any kind. It is not approved by the FDA or any comparable authority for human or veterinary use, it is an investigational compound with no approved formulation in any jurisdiction, and material supplied as a research chemical is not a clinical product. This product is not intended to diagnose, treat, cure, or prevent any disease. It must not be given to humans or animals. Purchase is restricted to qualified researchers and institutions operating within applicable laws. All handling is the responsibility of the purchasing laboratory.
20 reviews for Retatrutide 10mg