Retatrutide

Retatrutide (development code LY3437943) is a 39-residue synthetic peptide engineered to act as a triple agonist of the GIP, GLP-1, and glucagon receptors. The chromatogram and mass spectrometry data above are from the current shipping lot — no email gate, no document request, no proxy summary. What ships is what’s plotted.

This compound is supplied by Apex Laboratory as a high-purity research reagent for in-vitro laboratory research and development applications. It is not approved for human consumption, veterinary use, or any therapeutic application.

Compound Overview

Retatrutide differs from earlier metabolic peptides by simultaneously engaging three distinct G-protein-coupled receptors that regulate energy intake, energy expenditure, and glucose homeostasis. Semaglutide targets only GLP-1; tirzepatide targets GIP and GLP-1; retatrutide adds glucagon receptor agonism as the third axis, contributing to increased energy expenditure in published preclinical work.

Structurally, retatrutide is a 39-residue peptide assembled by solid-phase synthesis with three non-coded amino acid modifications: 2-aminoisobutyric acid (Aib) at positions 2 and 20 to confer DPP-4 resistance, and α-methyl-leucine (αMeL) at position 13 to optimize GIP receptor activity. A C20 fatty diacid moiety is attached to the lysine residue at position 17 via an AEEA-γGlu linker, enabling albumin binding and extended pharmacokinetic half-life. This long lipid tail is also responsible for the late retention time visible in the chromatogram above (~17.8 min) — the molecule is significantly more hydrophobic than smaller research peptides.

Research Background & Published Literature

Retatrutide is one of the most extensively studied incretin-family peptides published in the past five years. The phase 2 obesity trial reported by Jastreboff and colleagues in the New England Journal of Medicine demonstrated dose-dependent body weight reductions of up to 24.2% at 48 weeks in the 12 mg cohort, alongside improvements in glycemic control, blood pressure, and lipid markers. Earlier discovery and pharmacology data from Coskun et al. (Cell Metabolism, 2022) characterized the receptor binding profile and proof-of-concept activity in animal models.

Researchers exploring the published literature surrounding this compound can review the following peer-reviewed sources for additional context on its mechanism of action, signaling pathways, and experimental applications in controlled laboratory settings:

• Jastreboff et al. (2023) — Triple-Hormone-Receptor Agonist Retatrutide for Obesity: Phase 2 Trial (NEJM)
• Coskun et al. (2022) — LY3437943: Discovery and clinical proof of concept (Cell Metabolism)
• Sanyal et al. (2024) — Retatrutide phase 2a trial in metabolic dysfunction-associated steatotic liver disease (Nature Medicine)
• ClinicalTrials.gov NCT04881760 — Retatrutide phase 2 obesity study

Technical Specifications

Product Name	Retatrutide 10mg
Other Names	LY3437943 (Eli Lilly development code)
Classification	GIP / GLP-1 / Glucagon triple receptor agonist
CAS Number	2381089-83-2
Molecular Formula	C₂₂₁H₃₄₂N₄₆O₆₈
Molecular Weight	4731.33 g/mol
Sequence Length	39 amino acids with C20 fatty diacid modification at Lys17
Receptor Targets	GCGR (EC₅₀ 5.79 nM) · GIPR (EC₅₀ 0.064 nM) · GLP-1R (EC₅₀ 0.775 nM)
Purity Specification	≥99% (HPLC + MS verified — see chromatogram above)
Physical Form	Lyophilized powder · sealed glass vial
Recommended Diluent	Bacteriostatic water or sterile WFI
Intended Use	In-vitro research only — not for human consumption

Storage, Handling & Stability

Store the lyophilized vial at -20°C for long-term stability. Due to retatrutide’s larger molecular size (39 amino acids with a long fatty acid modification), reconstituted aliquots should be used within 14 days when stored at 2–8°C, and freeze-thaw cycles minimized through aliquoting consistent with your standard operating procedures.

• Minimize time at ambient temperature during handling to preserve compound integrity.
• Reseal the vial immediately after each withdrawal to limit moisture absorption.
• Use appropriate personal protective equipment and follow your institution’s chemical safety protocols at all times.
• Label aliquots with compound name, concentration, reconstitution date, and operator initials for full lot traceability.

Quality Assurance & Analytical Verification

Apex Laboratory applies a dual-verification protocol to every batch before it enters inventory. Each lot is screened by High-Performance Liquid Chromatography to confirm chromatographic purity and Mass Spectrometry to verify molecular identity — and the resulting data is published directly to this product page for the current shipping batch. The chromatogram and analytical summary at the top of this page are not a marketing graphic; they are this batch’s actual release data.

For larger peptides like retatrutide (4731 Da), mass spectrometry verification relies on identifying multiple charge states rather than a single molecular ion. The mass spec panel above shows the characteristic ESI+ envelope: the dominant [M+3H]³⁺ peak near m/z 1578, the [M+4H]⁴⁺ peak near m/z 1184, and a smaller [M+2H]²⁺ peak near m/z 2367. Together these confirm intact molecular weight without depending on any single signal — a more rigorous check than [M+H]⁺ alone for compounds in this size range.

Historical batch reports for prior lots are available on request. Email support@apexlaboratory.org with the lot number and we’ll send the full analytical record.

Frequently Asked Questions

Where can I see the Certificate of Analysis for this batch?

It’s published at the top of this page. The HPLC chromatogram, the purity value, the mass spectrometry confirmation showing multiple charge states, and the Quality Assurance signoff are all visible without a request, login, or email gate. Each batch update overwrites the displayed report so you always see the data for the lot currently shipping.

What makes retatrutide different from semaglutide or tirzepatide?

Retatrutide is a triple receptor agonist targeting GIP, GLP-1, and glucagon receptors simultaneously. Semaglutide targets GLP-1 alone; tirzepatide targets GIP and GLP-1. The added glucagon receptor agonism contributes to increased energy expenditure in published preclinical models — a mechanistic axis that monoagonist and dual-agonist research compounds do not engage.

Why does retatrutide have such a high molecular weight?

The 4731 Da molecular weight reflects retatrutide’s 39-amino-acid backbone plus a C20 fatty diacid moiety attached at Lys17 via an AEEA-γGlu linker. The fatty acid tail enables albumin binding for extended pharmacokinetic half-life, and is also responsible for the relatively late HPLC retention time (~17.8 min) visible in the chromatogram — a function of the molecule’s overall hydrophobicity in reversed-phase separation.

Why does the mass spec show multiple peaks instead of one?

Electrospray ionization (ESI+) produces a series of charge states for larger peptides rather than a single protonated molecular ion. For retatrutide, the most intense peaks are typically [M+3H]³⁺ and [M+4H]⁴⁺, with [M+2H]²⁺ visible at higher m/z. Identifying multiple charge states that all back-calculate to the same parent mass is a more rigorous identity check than relying on any single signal — and is standard practice for peptides above ~3,000 Da.

What is the primary research application of this compound?

Retatrutide is used in laboratory settings to study coordinated activation of the GIP, GLP-1, and glucagon receptor pathways — particularly incretin signaling, energy expenditure regulation, hepatic lipid metabolism, and combined metabolic hormone receptor pharmacology — within in-vitro and ex-vivo experimental systems.

Is this product approved for human use?

No. All compounds sold by Apex Laboratory are classified as chemical research reagents intended strictly for in-vitro laboratory research. They are not approved for human consumption, veterinary use, or any therapeutic application. Retatrutide remains an investigational pharmaceutical in clinical development by Eli Lilly and is not approved by any regulatory authority for human use as of this writing. Purchasers who imply intended bodily use will have their orders cancelled and their accounts permanently suspended.

Is bulk ordering available?

Yes. For bulk quantities, custom packaging requirements, or recurring supply agreements, contact support@apexlaboratory.org with the compound name, desired quantity, preferred dosage format, and your target delivery timeline. Volume pricing is available for qualifying institutional and recurring orders.

Related Research Compounds

Researchers studying triple-receptor and incretin-family pathways may also be interested in related compounds available from Apex Laboratory: Tirzepatide (GIP / GLP-1 dual agonist), Semaglutide (GLP-1 monoagonist), and Cagrilintide (amylin analog). For broader metabolic and longevity research selection, browse the complete Apex Laboratory research catalog, or visit the About page to read more about our HPLC and mass spectrometry verification process.

Shipping, Packaging & Delivery

All orders placed before 2:00 PM Eastern Time on a business day ship the same day via tracked domestic carriers. Retatrutide orders are packaged in insulated, temperature-appropriate containers designed to preserve compound stability during transit. On delivery, transfer the vial to -20°C storage immediately. For time-sensitive research protocols or special delivery windows, contact our support team in advance to coordinate optimal shipping timing for your laboratory workflow.

Research Use Disclaimer

For in-vitro research use only. Not for human consumption. All products sold by Apex Laboratory — including Retatrutide 10mg — are intended exclusively for qualified researchers, accredited laboratories, and educational institutions. Retatrutide is an investigational pharmaceutical compound that has not received marketing authorization from the FDA or any other regulatory authority for any indication. Purchasers assume full responsibility for safe handling, proper storage, and compliance with all applicable federal, state, and local laws, regulations, and institutional policies governing the purchase and use of chemical research reagents.