What is RETA (GLP-3)?

01

What is RETA (GLP-3) made of?

RETA (GLP-3) is one modified peptide chain, not a blend of separate peptides. The reference record lists the formula C221H342N46O68 and a molecular weight of about 4,731 g/mol (PubChem CID 171934787).

That mass is several times that of most catalog peptides, and the chemical modifications mean a sequence alone does not identify it. The identity result on the COA, a measured mass, is what confirms a lot.

Sources: [1] PubChem · reference structure

02

Where to buy RETA (GLP-3)

RETA (GLP-3) is sold direct by Prism Labs at prismlabs.store, in 20mg and 30mg vials from $124.99 per vial. The latest published lab report, tested October 26, 2026, measured 99.84% purity. Every lot’s certificate of analysis is on the product page, with a link to verify it with the testing lab.

Orders placed before 4:30 PM CT ship the same day, seven days a week, when the size is in stock. Standard shipping is free over $125. Packs of 2 or more vials are discounted, up to 18% off.

See RETA (GLP-3) sizes, prices and lab reports · How to vet any peptide supplier

03

Where did RETA (GLP-3) come from?

RETA (GLP-3) was described in 2022 in a paper that covered its design, its activity at three receptors in cell assays, studies in mice and a first single-dose study in people.

A larger phase 2 study followed in 2023. Compared with older catalog peptides, its literature is young and comes mostly from its developer’s program.

An older relative in the catalog is TIRZ (GLP-2), first described in 2018. It is designed to activate two related hormone receptors; RETA (GLP-3) is designed to activate three, the same two plus a third. They are separate molecules with different masses: What is TIRZ (GLP-2)?

Sources: [2] Cell Metabolism · 2022 · [3] New England Journal of Medicine · 2023 · [5] Molecular Metabolism · 2018

04

What has RETA (GLP-3) been studied for?

Published work falls into two groups:

• Receptor pharmacology: how strongly it activates each of its three target receptors in cell assays.
• Animal and clinical studies from the developer’s program.

Because the compound is young, read each paper for its model and measurements rather than relying on summaries.

These are observations in laboratory models. They are not evidence about any use in people.

Sources: [2] Cell Metabolism · 2022 · [3] New England Journal of Medicine · 2023

05

Why identity testing matters for large peptides

Longer chains give synthesis more places to go wrong: missing or extra amino acids, protecting groups that were not fully removed, and other related impurities. A 2014 review catalogs them.

HPLC purity shows how much of the sample is the main product; mass spectrometry shows whether that product has the right mass. For a peptide this size, read both results.

Sources: [4] Journal of Pharmaceutical and Biomedical Analysis · 2014

06

How is RETA (GLP-3) supplied and stored?

RETA (GLP-3) ships as a lyophilized (freeze-dried) powder in 20 mg or 30 mg vials. The powder is stable at room temperature in transit. For lab use it is reconstituted with bacteriostatic water such as Prism H2O.

Concentration is content divided by volume: 20 mg in 2 mL gives 10 mg per mL. The reconstitution calculator handles other combinations.

For storage before and after reconstitution, see how to store lyophilized peptides.

07

How do I verify RETA (GLP-3) batches?

Every lot has its own certificate of analysis from an independent lab. Read three results separately:

• Identity: confirms the expected compound was detected.
• Purity: the share of the measured material that is the intended compound.
• Content: the amount measured, compared with the label.

Then match the lot number on your vial or bottle to the report, and use the report’s verification link to confirm it with the testing lab. Step by step: how to read a peptide COA.