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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 AL (R), RETA-3, TA-R, GLP-3 R, GLP-3 RT, GLP-3 RTA, RETA-10, RETA-20, IP3-RT, PRL-3 RT, IPP-3 RT

Published July 22, 2026 · Updated October 26, 2026

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

Weight lossGLP-1/GIP/glucagon agonistInvestigational
Common vial size10 mg
Dose1 up to 12 mg per dose (start low, increase slowly)
FrequencyWeekly
RouteUnder the skin (subcutaneous)
StatusInvestigational
CycledNot cycled in the trials

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

See how this dose compares across the library →

01

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.

02

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.

  1. 01
    GLP-1 and GIP reduce how much you eat
    The same appetite and stomach-emptying effects as the approved drugs in this family.
  2. 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.
  3. 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.
Anatomical illustration highlighting metabolic organs
WHAT THIS COMPOUND ACTS ON:
GLP-1Fullness, slower stomachGIPInsulin after mealsglucagonBurns stored fuel
03

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.

Trial result: 28.3% (stayed on treatment) · 25.0% (everyone randomised). The first figure describes people who stayed on treatment and the second counts everyone who started. Our write-up of the published trial explains why both figures exist.

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.

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%.

The published record

Research index

288

Papers and trials about Retatrutide

Searched: Retatrutide, LY3437943, triple agonist, GLP-3R, Reta GLP-3, Trinity-X, LP3-R, GLP3-Reta.

Left out: reta (vendor listing code, appears in no journal); triple G (vendor listing code, appears in no journal); GLP-3 (vendor listing code, appears in no journal); GLP-3 retatrutide (vendor listing code, appears in no journal); R-30 (vendor listing code, appears in no journal); R30 (vendor listing code, appears in no journal); R20 (vendor listing code, appears in no journal); R5 (vendor listing code, appears in no journal); ratatouille (vendor listing code, appears in no journal); triple-G (vendor listing code, appears in no journal); GLP-3 (RT) (vendor listing code, appears in no journal); EZP-3P (vendor listing code, appears in no journal); R-10 (vendor listing code, appears in no journal); GLP-3 (RTA) (vendor listing code, appears in no journal); EP-3 R (vendor listing code, appears in no journal); AMP-3P (vendor listing code, appears in no journal); GLP-3 RT Research Peptide for Sale (vendor listing code, appears in no journal).

167 papers tagged human · 44 not reviews or lab · 11 clinical trial publications

34 registered trials · 2 with posted results

Furthest stage reached: Phase 3, completed, no results posted

Compare this against the whole library →

In animals66
In the lab2
Reviews125
Senior author shareSpread across many groups

Evidence summary

Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.

Retatrutide vial rendering
Compound field notes

At a glance

Four things to know about Retatrutide

01

Evidence

Investigational

02

Category

Weight loss and metabolic

03

Common vial

10 mg

04

Half-life

About 6 days

04

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 trials Trial 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 →

05

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.

06

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 mgTrial dose

Choose your mix

your own mL
units · —
Enter your own volume

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

YOUR DRAW20 / 100 units
What it costs

Retatrutide starts at $24.99 across 166 vendors, typically $3.20 – $11.33 per mg.

653 listings, last read Oct 24, 2026. Shipping and card fees are not included.

See all 653 listings →
07

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.

08

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.

Solubility, computed: 27% charged residues, 40% hydrophobic. Water usually sufficient.

A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.

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

Read what dehydration on it actually feels like and when to get help.

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

09

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.

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. Lilly said on July 23, 2026 that it plans to submit retatrutide to the FDA in the first quarter of 2027. A submission is not an approval. Standard review runs about ten to twelve months from acceptance, so a decision falls in late 2027 or 2028 and a prescription in a pharmacy realistically in 2028. The application type is itself disputed: the FDA has determined retatrutide is a drug rather than a biologic, and that question is before the Seventh Circuit.

What regulators say

From official documents

Enforcement naming this compound

  • Vendor product named as an unapproved new drug (Royal Peptides, August 2026)

    This is a finding about one seller's vial, not about the compound or any approved product containing it.

    Read the letter
10

More on Retatrutide

Also sold in a blend: Retatrutide + Cagrilintide blend

Guides for this compound

Sources

Beyond these, 288 records are indexed. Browse the records