Retatrutide is a glp-1/gip/glucagon agonist used for weight loss. Retatrutide is a triple agonist that switches on three hormone receptors at once: GLP-1, GIP, and glucagon. In plain terms: it copies three of your natural 'I'm full' and fat-burning signals together, which is why it drives some of the largest weight-loss numbers seen in trials. It is still experimental.

How much water do I add to Retatrutide?

You can reconstitute Retatrutide with 0.5, 1, or 2 mL of bacteriostatic water. Each option produces a different concentration and syringe draw for the same dose. Use the calculator to see which is easiest to measure.

What does Retatrutide cost per dose?

Cost per dose depends on vial size, price paid, and your dose. Enter your vendor's price in the Retatrutide calculator to see cost per dose and monthly cost.

What is the reference dose for Retatrutide?

The commonly referenced range is 1 up to 12 mg per dose (start low, increase slowly), taken weekly. This is reference information, not a recommendation. Talk to a licensed clinician.

What are the side effects of Retatrutide?

Reported side effects of Retatrutide include: Stomach side effects like nausea and vomiting are the main issue.; It must be increased slowly from a low dose over months, and it is not legally sold outside clinical trials.. Severity and frequency vary by person and dose.

Who should not take Retatrutide?

Retatrutide is generally not appropriate for: Not legally available outside clinical trials, so no prescriber is assessing whether it suits you; Pregnancy, or trying to become pregnant. Talk to a licensed clinician before starting.

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Decoding

Retatrutide_Dosage, benefits & legal status

Also known as LY3437943, reta, triple G, GLP-3, GLP-3 retatrutide, R-30, R30, R20, R5, triple agonist, ratatouille, triple-G, GLP-3R, GLP-3 (RT), Reta GLP-3, Trinity-X, EZP-3P, R-10, GLP-3 (RTA), LP3-R, EP-3 R, AMP-3P, GLP3-Reta, GLP-3 RT Research Peptide for Sale

By the Peptide Decoding Editorial Team

Published July 22, 2026 · Updated August 24, 2026

An experimental weekly shot with some of the biggest weight-loss numbers yet in trials.

Weight lossGLP-1/GIP/glucagon agonistInvestigational

InGLP-1 agonists

30 amino acidsFrom a chemical database

Sequence

▸ See the chain

YAQGTFTSDYSILLDKKAQAAFIEYLLEGG

Starts with tyrosine like tirzepatide, but diverges by the third residue. The fatty chain also sits three positions earlier than in either of the others, which is part of how the same class of molecule came to reach a third receptor.

Position 2 · Aib · substitution
Alpha-aminoisobutyric acid, shown as A. Blocks the enzyme that would cut the chain in two.
Position 13 · alpha-methyl-Leu · substitution
A methylated leucine, shown as L. Confirmed as a modified residue in the deposited structure.
Position 17 · K · acylation
A C20 fatty diacid chain. Semaglutide and tirzepatide both attach theirs at position 20; retatrutide moves it to 17.
Position C-terminus · amidation

Common vial size10 mg

Dose1 up to 12 mg per dose (start low, increase slowly)

FrequencyWeekly

RouteUnder the skin (subcutaneous)

StatusInvestigational

MixYour choice, calculate it

CycledNot cycled in the trials

Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.

What is Retatrutide?

Plain language first. The technical label stays, but it never stands alone.

Overview

It copies three of your natural 'I'm full' and fat-burning signals together, which is why it drives some of the largest weight-loss numbers seen in trials. It is still experimental.

The technical version

Retatrutide is a triple agonist that switches on three hormone receptors at once: GLP-1, GIP, and glucagon.

What it's used for

People follow it for very large weight loss, around a quarter to nearly a third of body weight in trials. It acts on three appetite and metabolism pathways at once.

How does Retatrutide work?

What it does in the body, and where.

Retatrutide adds a third target, glucagon, to the two tirzepatide already hits. Glucagon is the interesting one, because it does something the others do not.

01
GLP-1 and GIP reduce how much you eat
The same appetite and stomach-emptying effects as the approved drugs in this family.
02
Glucagon raises how much you burn
It pushes your body to spend more energy at rest, rather than only taking in less. That is a different lever from the other two.
03
More receptors has meant more weight loss, and more side effects
Trial figures are the largest in this class so far, but it is investigational, so nobody yet knows how it behaves over years.

Receptors

Hits 3 receptors at once.

What else is it used for?

Each group carries its own evidence level.

Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.

Weight loss

Investigational

Human trialIn a 48-week mid-stage trial, average weight loss reached 24.2% on the top dose against 2.1% on placebo.
Human trial83% of people on the top dose lost at least 15% of their body weight, and a quarter lost more than 30%.
Human trialIn a late-stage trial reported in December 2025, average loss was 28.7% at 68 weeks, the largest late-stage weight-loss result reported so far.
Human trialIn a second late-stage trial reported in May 2026, loss was roughly 25 to 28% at 80 weeks, with a subgroup reaching about 30% at two years.

Study

Phase 2 trial, New England Journal of Medicine, 2023

Liver fat and joint pain

Investigational

Human trialFat in the liver dropped by 82.4% on average at 24 weeks, against essentially no change on placebo.
Human trial86% of people reached a normal liver-fat level by 24 weeks, rising to 93% by 48 weeks.
Human trialKnee osteoarthritis pain scores fell by up to 75.8%.

Study

Liver fat substudy, Nature Medicine, 2024

The published record

Research index

256

Records indexed for Retatrutide

151 in humans, 39 of them original studies.

34 registered trials, 2 with posted results.

FDA: Named as an unapproved new drug.

Browse the records

In animalsPro

In the labPro

ReviewsPro

Senior author sharePro

Counted from Europe PMC indexing, not read by a person. Human means indexed under humans, which includes reviews and work on human cells. Original studies exclude reviews and lab work on human cells.Last updated 11 September 2026.

Compound field notes

At a glance

Four things to know about Retatrutide

Evidence

Investigational

How much, and do you cycle it?

The range, and whether you take breaks.

1 up to 12 mg per dose (start low, increase slowly), weekly. Not cycled in the trialsTrial dose

Given continuously for the whole study period: TRIUMPH-1, 80 weeks with an extension to 104. The dose is stepped up at the start, which is a ramp rather than a cycle, and no trial in this class built in a planned break.

Compare this against the whole library →

How long does it stay in the body?

The half-life, and where the figure comes from.

About 6 daysTrial protocol

Not yet traced to a primary source.

You can compare this against the whole library to see where it sits.

How do I dose and price it?

Enter your vial and your dose. Pick a mix. We show the draw and the cost.

The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.

Your vial size (mg)

Printed on the vial.

What you paid per vial

Used for cost per dose only.

Your dose (mg)

Commonly referenced range: 1 up to 12 mg per dose (start low, increase slowly)Trial dose

Choose your mix

0.5 mL water5units · 20 mg/mL

Half a 100-unit syringe

1 mL water10units · 10 mg/mL

One full 100-unit syringe

Easiest

2 mL water20units · 5 mg/mL

Two full 100-unit syringes

your own mL

units · —

Enter your own volume

Measuring the water1 mL = one full 100-unit syringe.

Your draw

20 / 100 units

Full calculator with reorder date →Read a syringe →

What it costs

Retatrutide starts at $34.00 across 63 vendors, typically $3.95 – $13.80 per mg.

256 listings, last read Sep 6, 2026. Shipping and card fees are not included.

See all 256 listings →

How do you store it?

Before mixing, and after.

Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.

Unmixed lyophilized Retatrutide keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.

What are the side effects and cautions?

Known cautions and warnings for this compound.

Handling note

Vials sold as "GLP-3" are retatrutide. There is no hormone called GLP-3. The name was invented by counting receptors: semaglutide hits one, tirzepatide hits two, retatrutide hits three, so sellers numbered them. The numbering is not real biology, and GLP-2 is already the name of a different intestinal hormone that has nothing to do with weight loss. Look for the word retatrutide or the code LY3437943, which is what appears in the scientific and regulatory record. Codes like R5, R20 and R30 refer to the milligrams in the vial, not the dose.

Who should avoid it

Check these before anything else.

Not legally available outside clinical trials, so no prescriber is assessing whether it suits you
Pregnancy, or trying to become pregnant

Stop and get help

These are emergencies. Seek care.

Severe stomach pain that spreads to your back
Vomiting badly enough that you cannot keep fluids down
Signs of an allergic reaction

Common effects

Expected, and usually mild.

Nausea, vomiting, and diarrhea, which increase at higher doses
Odd skin sensations such as tingling or numbness, reported in trials
Urinary tract infections
A mild temporary rise in heart rate

What regulators say

FDA: Warning letter to Royal Peptides LLC, MARCS-CMS 734884, August 24, 2026: unapproved new drugs, misbranded
Named as an unapproved new drug
Checked 11 September 2026

Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.

Is Retatrutide approved?

And where the numbers on this page come from.

No. Retatrutide is not approved anywhere and is currently in company-run clinical trials. There is no legal route to obtain it outside a trial.

Approval status
Investigational
Route
Under the skin (subcutaneous)
Checked
August 2026

What has happened recently

Not approved in any country. Lilly has said it plans to file for FDA approval in the first quarter of 2027, pushed back from an earlier timeline while manufacturing and quality data are assembled. On August 12, 2026, Lilly filed six federal lawsuits against US sellers of black-market retatrutide, naming Aesthetic Envy Cosmetic Centers, Astra, Legendary Peptides, Striker Pharmacy, Texas Peptides and Lone Star Peptide. Four of the six were filed in Texas. The company also said it had referred more than 200 individuals and entities to the FDA, the Department of Justice, state attorneys general and licensing boards, and reported more than 14,000 listings across over 100 countries. Alongside the filings it asked payment processors, credit card companies, e-commerce platforms and shipping carriers to cut sellers off. The FDA has stated that selling unapproved retatrutide to consumers is illegal and that it cannot lawfully be compounded. A "research use only" label does not change that.

You can compare this against the whole library, or read how to check a seller.

DoseFrom published clinical trials. Not approved by a regulator for this dose.
Vial sizeFrom what vendors typically list; not a recommendation.
Sources
Drugs.com, retatrutide development history AJMC, TRIUMPH-1 phase 3 results Phase 2 trial, New England Journal of Medicine, 2023 Liver fat substudy, Nature Medicine, 2024 Retatrutide entry, WHO International Nonproprietary Names / ClinicalTrials.gov Eli Lilly, statement on retatrutide black-market enforcement
Reviewed14 August 2026

What else is like Retatrutide?

Others in GLP-1 agonists, side by side.

If you're weighing Retatrutide, it's worth reading Liraglutide, Survodutide, and Mazdutide in the same class.

YOU ARE HERE

Retatrutide

An experimental weekly shot with some of the biggest weight-loss numbers yet in trials.

Investigational

Dose: 1 up to 12 mg per dose (start low, increase slowly)
How often: Weekly

LIRA

Liraglutide

A daily version of the Ozempic-style shot for weight loss and blood sugar.

FDA-approved

Dose: 0.6 up to 3 mg per day (start low, increase slowly)
How often: Daily

SURVO

Survodutide

An experimental weekly shot for weight loss and fatty-liver disease.

Investigational

Dose: 2.4 up to 6 mg per week (start low, increase slowly)
How often: Weekly

MAZDU

Mazdutide

An experimental weekly weight-loss shot (approved in China) that also helps blood sugar and cholesterol.

Investigational

Dose: 2 up to 9 mg per dose (start low, increase slowly)
How often: Weekly

Browse the full GLP-1 lineup

See the full GLP-1 comparison

Compared with

Retatrutide vs Tirzepatide

Retatrutide's 28.3 percent is being set against tirzepatide's 22.5 percent. Different trials, different lengths, and one of the numbers comes from a press release.

Read comparison →

Guides for this compound

How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
Why Does My Peptide Injection Itch or Welt
Injection-site irritation, a histamine reaction, or a true allergy, and how to tell them apart.
How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.

Sources

Drugs.com, retatrutide development history(2026)
Development timeline confirming it remains unapproved.
AJMC, TRIUMPH-1 phase 3 results(2026)
TRIUMPH-1 phase 3, 2,339 participants over 80 weeks.
Phase 2 trial, New England Journal of Medicine, 2023
Liver fat substudy, Nature Medicine, 2024
Retatrutide entry, WHO International Nonproprietary Names / ClinicalTrials.gov(2026)
The compound is registered as retatrutide, development code LY3437943. No trial or regulatory document uses the term GLP-3.
Eli Lilly, statement on retatrutide black-market enforcement(2026)
Six lawsuits filed 12 August 2026 against US compounding pharmacies, medical spas and online sellers. Over 200 entities referred to regulators, over 14,000 listings reported across more than 100 countries.

Last reviewed 14 August 2026

Beyond these, 256 records are indexed. Browse the records