GLP-3 RT (LY3437943) is available from US research peptide suppliers under Research Use Only (RUO) labeling for in vitro laboratory work. It is not FDA-approved for any therapeutic use, is not a controlled substance, and is not subject to the compounding pharmacy framework that governs prescription peptides. The single most important variable when sourcing it is COA quality — specifically whether the supplier provides independent third-party mass spectrometry to confirm molecular identity, not merely HPLC purity. Because no pharmacopeial reference standard exists for this compound, identity verification is more critical than for approved dual agonists such as GLP-2 TRZ.
Evo Peptides supplies GLP-3 RT in 15 mg, 20 mg, and 30 mg formats. Current lot-specific third-party HPLC purity values are 99.27%, 99.85%, and 99.91% respectively. Batch-specific third-party COAs (including mass spectrometry) are available for review before purchase. Fulfillment is from Wisconsin with same-day shipping on orders placed before 3:00 PM CST.
Research Use Only (RUO). This material is intended solely for in vitro laboratory research. It is not for human or veterinary administration, consumption, or any clinical use. These statements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Purchasers must be 21 years of age or older and acknowledge research-only intent.
GLP-3 RT (LY3437943) is an investigational compound currently in Phase 3 clinical development. It is not FDA-approved for any therapeutic indication. It is also not a scheduled substance under the Controlled Substances Act and does not appear on federal controlled substance lists. US research peptide vendors may legally offer it under Research Use Only (RUO) labeling for in vitro laboratory research.
GLP-3 RT's availability through the RUO channel is legally distinct from the FDA compounding pharmacy framework (including 503A bulk substance lists and PCAC reviews). That framework regulates which bulk drug substances licensed compounding pharmacies may use to fill prescriptions. It does not govern research peptide suppliers operating under RUO labeling. GLP-3 RT remains available through the RUO channel unless and until it receives FDA approval or is scheduled — neither of which is currently the case.
Researchers purchasing for legitimate in vitro or approved preclinical animal studies operate within the established legal framework for RUO materials. Purchasing or using the material for human administration falls outside that framework and is not permitted. For related context on compounding developments affecting other research peptides, see the BPC-157 FDA status 2026 guide.
RUO labeling designates the product for in vitro laboratory research only. It is a legal use designation, not a loophole. Vendors market and sell under this classification; buyers acknowledge research-only intent at the time of purchase. The RUO channel is governed differently from the prescription compounding channel and does not authorize human or veterinary use.
Most long-established research peptides have undergone market selection: vendors producing poor-quality material tend to lose researcher trust over time. GLP-3 RT presents three compounding challenges that raise the analytical bar.
First, it is a relatively new synthesis target for many research suppliers. Interest following Phase 2 data brought in vendors with limited prior experience synthesizing lipidated 39-residue triple agonists. Synthesis errors can produce material that shows high HPLC purity yet contains incorrect sequence or missing lipid modification — failures that pass a purity screen but fail functional assays.
Second, no pharmacopeial reference standard exists for GLP-3 RT. Approved dual agonists benefit from FDA-recognized reference standards that independent laboratories can anchor identity confirmation to. For GLP-3 RT no such standard is available. Mass spectrometry of the intact sequence (including the C18 lipid) is therefore the definitive identity test. A COA that reports only HPLC purity leaves open the possibility of a pure but incorrect compound.
Third, the compound sits at the higher end of typical research-catalog pricing, which can create pressure to reduce analytical costs while keeping list prices competitive.
A Certificate of Analysis is the primary document that describes what is in a given vial. For many research peptides HPLC purity is a useful first filter. For GLP-3 RT it is insufficient by itself: without a reference standard, HPLC shows only that a pure substance is present, not that the substance is GLP-3 RT. For general guidance on interpreting peptide COAs, see how to read a peptide COA. Below are the minimum elements a sufficient GLP-3 RT COA should include, and common shortfalls that do not meet research-grade expectations.
The figures below are lot-specific HPLC purity values from independent third-party COAs for material currently offered. Full COAs (including mass spectrometry) are accessible on the product page and at evopeptidesus.com/coas prior to purchase.
At 95% purity, up to 5% of a lipidated triple-agonist sample may consist of uncharacterized impurities — truncation sequences, de-lipidated species. These can shift dose-response curves and increase inter-experiment variability. At 99.9% the impurity floor is far lower. For comparative designs in which the glucagon-receptor contribution is a primary variable, the difference is experimentally relevant.
The following patterns suggest a supplier is unlikely to meet the analytical standards required for reproducible research. Any one of them warrants additional scrutiny before purchase.
When both GLP-3 RT and GLP-2 TRZ are sourced for parallel research designs, the same COA expectations apply to both. The underlying identity-verification challenge is greater for the unapproved triple agonist. See the GLP-2 TRZ vs GLP-3 RT research comparison for study-design considerations.
| Factor | GLP-2 TRZ | GLP-3 RT |
|---|---|---|
| FDA approval status | Approved | Investigational |
| Pharmacopeial reference standard | Exists | Does not exist |
| MS identity confirmation | Important | Non-negotiable |
| Receptor targets | GLP-1 + GIP (dual) | GLP-1 + GIP + Glucagon (triple) |
| Market maturity | Higher — more established vendors | Lower — newer synthesis target |
| Typical research price range | ~$60–$90 / vial | ~$85–$130 / vial |
| Minimum HPLC purity (research grade) | ≥99% for both | |
| Current Evo Peptides lot purity | See product page | 99.27% / 99.85% / 99.91% by variant |
| Source | GLP-2 TRZ product page | GLP-3 RT product page |
Lipidated peptides require careful handling. The C18 fatty-acid modification that extends half-life in vivo models also increases susceptibility to aggregation under suboptimal reconstitution conditions. The protocols below apply to lyophilized material as supplied. For broader guidance across peptide classes, see the peptide storage and reconstitution guide. Bacteriostatic water is available for laboratory reconstitution kits.
Each freeze-thaw cycle after reconstitution degrades the compound. Prepare single-use aliquots before freezing. Once thawed, do not refreeze. Snap-freezing in liquid nitrogen is preferred when −80 °C long-term storage is planned.
Understanding the research questions asked of GLP-3 RT clarifies which analytical requirements are most critical for a given protocol. The compound is examined across several mechanistic axes, each with different endpoint needs. See the GLP-3 RT research guide for mechanism detail and cited Phase 2 data.
The glucagon-receptor component distinguishes GLP-3 RT from dual agonists. In rodent models, glucagon-receptor agonism is associated with increased energy expenditure beyond GLP-1 agonism alone, involving brown-adipose-tissue thermogenesis and hepatic glucose oxidation. Lipidation confirmation in the COA is especially relevant for these endpoints because de-lipidated material exhibits altered pharmacokinetics.
Triple-agonist studies in diet-induced obesity models examine fat-mass reduction relative to lean-mass preservation. Parallel designs comparing GLP-3 RT with GLP-2 TRZ allow attribution of differences to the glucagon-receptor axis. Sourcing both compounds from the same supplier under consistent analytical methods reduces a common source of experimental confound.
Glucagon-receptor activation has established roles in hepatic glucose production and emerging roles in hepatic lipid handling. Studies in NASH/NAFLD models frequently use liver triglyceride quantification and histological scoring as primary readouts. Intact lipidation is again relevant because pharmacokinetic differences alter hepatic exposure.
Head-to-head designs that place GLP-3 RT and GLP-2 TRZ in the same model system allow direct attribution of effects to the glucagon-receptor contribution. For mechanistic comparison and study-design notes, see GLP-2 TRZ vs GLP-3 RT: research comparison.
Evo Peptides offers GLP-3 RT in 15 mg, 20 mg, and 30 mg formats with independent third-party HPLC and mass-spectrometry verification on every batch. Lot-specific COAs are available for review on the product page before purchase. Orders placed before 3:00 PM CST ship the same business day from Wisconsin. Standard credit/debit processing and cryptocurrency are accepted.
Orders placed before 3:00 PM CST ship the same business day from Wisconsin to all 50 states. Credit card, debit card, and cryptocurrency accepted. Free shipping on orders over $200. All material is supplied under Research Use Only labeling.
Yes, under Research Use Only conditions. GLP-3 RT (LY3437943) is not a scheduled or controlled substance. US research peptide suppliers may offer it under RUO labeling for in vitro laboratory work. It is not FDA-approved and may not be purchased or used for human or veterinary administration. The FDA compounding pharmacy framework does not govern RUO research vendors and does not determine availability through this channel.
At minimum: HPLC purity of 99% or higher with chromatogram available; mass spectrometry identity confirmation (observed mass consistent with the intact sequence including lipid, ~4,900 Da); the independent testing laboratory's name; a batch/lot number matching the vial; and an issue date within approximately 12 months. A purity-only COA is insufficient for GLP-3 RT. See the COA evaluation guide for additional detail.
Approved dual agonists have FDA-recognized pharmacopeial reference standards. GLP-3 RT (LY3437943) has no FDA approval and therefore no such standard. Mass spectrometry of the sequence and lipid modification is the practical identity confirmation method; HPLC alone cannot establish identity without a reference compound.
GLP-3 RT (LY3437943) is a triple agonist of GLP-1, GIP, and glucagon receptors currently in Phase 3 clinical development. GLP-2 TRZ is a dual GLP-1/GIP agonist that is FDA-approved. The compounds differ in sequence, molecular weight, lipid modification, and receptor profile. See the GLP-3 RT research guide for mechanistic context.
Store lyophilized material at −20 °C, protected from light and moisture. Reconstitute with bacteriostatic water or 0.1–1% sterile acetic acid — add solvent slowly, swirl gently, do not vortex. After reconstitution store at 4 °C and use within 14 days, or aliquot and freeze at −80 °C. Avoid freeze-thaw cycles. Full protocols are in the peptide storage guide.
Yes. For designs that compare dual versus triple receptor agonism, sourcing both compounds from the same supplier under consistent COA methodology reduces analytical confounds across study arms.
Material from US suppliers that provide independent third-party testing typically falls in the approximate $85–$130 per vial range. Pricing substantially below this range often warrants closer examination of the COA and testing methodology.