Retatrutide
Thirty-nine residues, four of which are not standard amino acids, with a twenty-carbon diacid chain hung off a lysine in the middle. Among the most heavily engineered molecules in this catalog — almost nothing about it is natural except the scaffold it was drawn on.
- Class
- Synthetic lipidated peptide (39 residues), C-terminally amidated
- Also written
- LY3437943
- CAS number
- 2381089-83-2
- Molecular formula
- Not stated. Published formulas and masses for this peptide disagree with one another, so neither is given here rather than printing a figure we cannot stand behind.
- Appearance
- White lyophilised powder
- Purity specification
- 99%+ by HPLC
- Vial size stocked
- 20 mg
Structure
Y – Aib – Q G T F T S D Y S I – αMeL – L D – K(C20 diacid–γGlu–AEEA) – A Q – Aib – A F I E Y L L E G G P S S G A P P P S – NH2
Four non-standard features carry this molecule. Two residues of 2-aminoisobutyric acid (Aib), at positions 2 and 20, which is an α,α-disubstituted amino acid no ribosome makes. One residue of α-methylleucine (αMeL) at position 13. A C20 diacid fatty chain attached to the lysine at position 17 through a γ-glutamate and an AEEA spacer — the lipidation. And an amidated C-terminus. Strip those away and what remains is a glucagon-family scaffold; they are the reason it is a distinct compound.
Origin
Retatrutide was developed by Eli Lilly and is designated LY3437943. Its backbone is drawn from the glucagon/GIP/GLP-1 peptide family, but the engineering — the Aib substitutions, the methylated leucine, the lipidation — is entirely synthetic and appears in no natural hormone. It is made by solid-phase synthesis.
Solubility
The lipidation changes the picture from a plain peptide. The C20 chain is strongly hydrophobic and makes this molecule markedly surface-active: it will foam if agitated, and material lost to foam is material lost. Direct the diluent down the wall, swirl gently, and give it time.
Storage and handling
- Lyophilised powder: store at −20 °C, protected from light and moisture.
- Never shake. Of everything in this catalog, a lipidated peptide is the one most punished by agitation.
- In solution: refrigerate, protect from light, and treat the working life as far shorter than that of the powder.
- Avoid repeated freeze-thaw cycles; aliquot first if the solution will be drawn on more than once.
- Label every reconstituted vial with compound, lot, concentration and date.
How your lot is verified
An independent third-party laboratory tests the material first, then we test it again in-house when it arrives — purity by HPLC, identity by mass spectrometry — and only then does it ship. On a 39-mer carrying four engineered modifications there is a great deal that can go subtly wrong in synthesis, and both measurements earn their place. How we verify.
Supplied for laboratory research use only. Not for human or veterinary use. No statement on this page has been evaluated by the Food and Drug Administration, and nothing here is intended to diagnose, treat, cure, or prevent any disease. Alpha Aminos is a chemical supplier and does not provide guidance on the use of any compound.