GLP-3 RT (Retatrutide)

Onyx Research carries GLP-3 RT in 5mg, 10mg, 15mg, 20mg, 30mg and 60mg vials. Each holds retatrutide as dry freeze-dried powder, and GLP-3 RT is a GIP, GLP-1 and glucagon receptor agonist. Onyx Research supplies it for in-vitro research.

GLP-3 RT is the Onyx Research label name for retatrutide. The 3 counts the receptors it acts on (GIP, GLP-1 and glucagon), and RT is short for retatrutide.

Besides single vials from 5mg to 60mg, GLP-3 RT comes in multi-vial packs: 5mg and 20mg 3-packs, a 20mg 5-pack and a 10mg trio. Packs suit longer studies that need several vials from the same order.

GLP-3 RT certificate of analysis

Freedom Diagnostics, an independent US lab, tested GLP-3 RT for Onyx Research using HPLC-UV for purity and mass spectrometry for identity. The certificates sit in the gallery next to the vial photos.

• GLP-3 RT 10mg: 99.613% purity, reported 2/28/2026, search code ONYX2602270065
• GLP-3 RT 20mg: 99.924% purity, reported 11/24/2025, search code Onyx2511200075
• GLP-3 RT 30mg: 99.936% purity, reported 11/24/2025, search code Onyx2511200074
• GLP-3 RT 60mg: 99.849% purity, reported 3/12/2026, search code ONYX2603110094

Our labels promise 99% purity, and the reports above come in at up to 99.936%. Enter the search code on the Freedom Diagnostics site to pull up the same report yourself.

What is GLP-3 RT (retatrutide)?

Retatrutide (LY3437943) is a single 39-amino-acid peptide from Eli Lilly that acts on three receptors at once: GIP, GLP-1 and glucagon. That makes it the first triple hormone receptor agonist to reach late-stage trials.

A fatty acid side chain lets it bind albumin in the blood, which stretches its half-life to about six days and makes once-weekly study possible. It isn’t approved anywhere yet.

What it does at the cell level

Retatrutide hits three receptors with one peptide: GIP, GLP-1 and glucagon. The first two are incretins that boost glucose-dependent insulin release and, in GLP-1’s case, curb appetite and slow stomach emptying.

The glucagon part is the unusual bit. Glucagon raises energy expenditure and pushes the liver to burn fat, so pairing it with the incretins is meant to work on both sides of energy balance. That’s the main reason researchers compare it with the dual and single agonists.

GLP-3 RT specifications

• Compound: GLP-3 RT (retatrutide)
• Onyx Research label code: GLP-3 RT
• Also known as: LY3437943
• CAS number: 2381089-83-2
• Molecular weight: 4,731.3 g/mol
• Structure: 39 amino acids with a fatty diacid side chain
• Sizes: 5mg, 10mg, 15mg, 20mg, 30mg, 60mg
• Other options: 5mg – 3pack, 10mg – Trio (3 vials), 20mg – 3pack, 20mg – 5pack
• Form: lyophilized (freeze-dried) powder in a crimp-sealed glass vial
• SKU: ONYX-GLP3RT
• Use: laboratory research only

Research findings

Jastreboff and colleagues reported the phase 2 obesity trial in the New England Journal of Medicine in 2023. At the highest dose, average weight loss reached 24.2% at 48 weeks, the largest figure any incretin compound had shown at that stage.

A substudy in Nature Medicine (Sanyal and colleagues, 2024) found large drops in liver fat, and a separate phase 2 trial in type 2 diabetes was published in The Lancet in 2023. Lilly’s phase 3 TRIUMPH program is testing it in obesity, diabetes, knee osteoarthritis and sleep apnea.

You can read the original papers through this PubMed search for Retatrutide, a free database from the U.S. National Library of Medicine.

How GLP-3 RT compares

GLP-3 RT acts on three receptors: GIP, GLP-1 and glucagon. Other compounds in the same area take different routes:

• AOD-9604 is the 176-191 tail of growth hormone, studied for fat breakdown
• MOTS-c is a short peptide encoded in mitochondrial DNA that switches on AMPK
• GLP-2 TZ (GLP-2 TZ, tirzepatide) acts on two incretin receptors, GIP and GLP-1
• GLP-1 SM (GLP-1 SM, semaglutide) is a once-weekly GLP-1 receptor agonist with a fatty-acid side chain
• Cagrilintide is a long-acting amylin analog, a fullness signal that runs apart from GLP-1

Metabolic research comes at weight from several directions: incretin receptors, amylin, glucagon, a growth hormone fragment and the mitochondria. Every one of them is in stock in our weight loss peptides.

GLP-3 RT dilution chart

Pick your water volume first and the strength follows from it. With the 5mg vial:

• Add 1mL: 5mg/mL (500mcg per 0.1mL, or 10 units on a U-100 syringe)
• Add 2mL: 2.5mg/mL (250mcg per 0.1mL, or 10 units on a U-100 syringe)
• Add 3mL: 1.67mg/mL (166.7mcg per 0.1mL, or 10 units on a U-100 syringe)

Bring the vial up to room temperature and clean the stopper with an alcohol pad. Inject the bacteriostatic water against the glass wall, not onto the powder, and swirl slowly until it’s clear. Shaking whips up foam and can damage the chain.

Storage and stability

Sealed the peptide lasts longest frozen at -20°C and dark. The fridge is fine for short spells. Mixed solution stays at 2 to 8°C and should be used within roughly 28 days.

Let a frozen vial come up to room temperature before you open it, or condensation forms on the powder.

What to check on delivery

The Onyx Research label names the compound and the amount. Compare both with your order confirmation, and check the crimp seal before the vial goes into storage.

The powder should look dry and pale, either as a solid cake or loose granules. If the cake has crumbled in the box, that’s expected. Powder that looks wet, gummy or off-color is not, so keep that vial out of use and send us a photo.

A one-line note per vial is enough: date received, date mixed and how much diluent went in.

GLP-3 RT options and prices

All 10 options are on this page. Choose one from the option menu above the cart button:

• 5mg: $45.00
• 5mg – 3pack: $110.00
• 10mg: $99.00
• 10mg – Trio (3 vials): $219.00
• 15mg: $130.00
• 20mg: $165.00
• 20mg – 3pack: $420.00
• 20mg – 5pack: $600.00
• 30mg: $195.00
• 60mg: $390.00

The 30mg size works out cheapest per milligram, at about $6.50 per mg against $9.90 for the 10mg. The small vial is the better pick for a pilot run.

Related products

• AOD-9604 5mg, an hGH fragment
• GLP-2 TZ 10mg (Tirzepatide), a GIP/GLP-1 agonist
• Tesamorelin 10mg, a GHRH analog
• Cagrilintide 10mg, an amylin analog
• GLP-1 SM 10mg (Semaglutide), a GLP-1 agonist

See everything in our weight loss peptides, or start from the Onyx Research home page to browse every category.

Questions people ask

How much is in a GLP-3 RT vial?

5mg, 10mg, 15mg, 20mg, 30mg and 60mg, depending on the size you pick.

How does ordering work?

Choose the size, press add to cart and go through checkout. You can add bacteriostatic water and anything else to the same order.

Is there a lab report?

Yes. The certificate of analysis is in the product photos, and the purity results are listed on this page.

What is in GLP-3 RT?

Retatrutide. This compound is the name printed on the Onyx Research label.

Is there a crypto discount?

Yes. Onyx Research gives an extra discount on orders paid with crypto, applied at checkout.

Buy GLP-3 RT from Onyx Research

Order GLP-3 RT now from from $45.00. It’s in stock, and shipping is free on every order.

Crypto payments get an extra discount, applied at checkout.

Many labs pair it with something from our weight loss peptides.

Research use only. Onyx Research supplies this material to qualified labs for in-vitro work. It’s not a medicine, supplement, food or cosmetic, and it must not be given to people or animals. No statement here has been reviewed by the FDA.