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Retatrutide

Last reviewed: April 18, 2026 by The Peptide Catalog Team

A next-generation triple-action weight loss peptide — up to 24% in clinical trials. Retatrutide is an investigational triple agonist targeting GIP, GLP-1, and glucagon receptors simultaneously. Phase 2 trials showed unprecedented 24% weight loss at the highest dose — the most ever recorded for any obesity medication. Currently in Phase 3 clinical trials, it represents the next generation of metabolic therapies.

CategoryWeight Loss & Metabolic Peptides
ClassGLP-1 agonist
GoalFat Loss
Overview

Core Benefits

Key Advantages
~24% weight loss
Highest weight loss of any peptide in trials at top dose.
Triple-receptor agonist
Hits GIP, GLP-1, and glucagon for maximum metabolic effect.
Increased calorie burn
Glucagon arm raises resting energy expenditure.
Strong glucose control
Near-normalizes HbA1c in many Phase 2 participants.
Weekly dosing
Once-weekly subcutaneous injection, like tirzepatide.
Phase 3 ongoing
Eli Lilly Phase 3 readout expected to confirm Phase 2 results.

These are educational summaries of commonly discussed effects in wellness/regenerative contexts, not guarantees.

Retatrutide Results Timeline

Progression
1
Week 1–4
Physical Changes
Rapid weight loss begins (4-8 lbs), very strong appetite suppression
Performance & Recovery
Dramatic reduction in hunger, early satiety after small meals
Other Benefits
GI side effects common (nausea, diarrhea), dose titration period
2
Month 2–3
Physical Changes
Accelerated weight loss (10-18%), rapid body transformation
Performance & Recovery
Minimal hunger between meals, easy caloric deficit
Other Benefits
Blood sugar often normalizes, increased energy from glucagon action
3
Month 4–6
Physical Changes
Substantial weight loss (18-22%), significant fat reduction
Performance & Recovery
Improved stamina from lower body weight, thermogenesis boost
Other Benefits
Metabolic markers improve dramatically, sustained energy
4
6+ Months
Physical Changes
Up to 24%+ weight loss possible (based on Phase 2 data)
Performance & Recovery
Exercise capacity increases, body recomposition
Other Benefits
Continue until goal weight reached; long-term use expected for maintenance

Timeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.

Read the full Retatrutide results timeline →

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Evidence at a glance

Two parallel grades per outcome — clinical RCT depth and real-world community adoption. See the Research Overview below for citations and detail.

OutcomeClinical EvidenceCommunity Evidence
Body weight reduction (obesity)StrongPreliminary
HbA1c reduction in T2DStrongPreliminary
Hepatic steatosis (MASLD)ModeratePreliminary
Cardiovascular outcomesPreliminaryPreliminary
How It WorksTriple Agonist — GIP/GLP-1/Glucagon Receptor

Receptor → Metabolic Cascade → Weight & Glucose → Outcomes

1
Target

GIP + GLP-1 + Glucagon Receptors — Triple Activation

Retatrutide is the first triple agonist, adding glucagon receptor activation to the dual GIP/GLP-1 mechanism of tirzepatide. Glucagon increases energy expenditure and fat oxidation — adding a "burn more" signal to the "eat less" effect.

2
Cellular Signal

Triple cAMP Activation → Maximum Metabolic Effect

GLP-1: appetite suppression + insulin secretion. GIP: enhanced fat metabolism + beta cell support. Glucagon: increased hepatic glucose output + thermogenesis + fat oxidation. The three pathways together create the most comprehensive metabolic intervention available.

3
Systemic Effect

Eat Less + Burn More → Maximum Weight Loss

Phase 2 trials showed up to 24% body weight loss at 48 weeks — potentially the highest of any weight-loss medication. The glucagon component drives energy expenditure that the dual agonists lack. Still investigational.

4
What You Notice

Strong Appetite Reduction + Increased Energy Expenditure

Pronounced appetite suppression plus a subtle increase in energy expenditure (from glucagon). Weight loss is rapid and significant. GI side effects require careful titration. Currently in Phase 3 trials — not yet FDA-approved.

What Makes This Peptide Different

Retatrutide represents the next generation beyond tirzepatide. The addition of glucagon receptor activation creates a dual mechanism: reduced intake (GLP-1/GIP) AND increased expenditure (glucagon). This "eat less + burn more" combination may produce the greatest weight loss of any pharmaceutical intervention. Still investigational — follow research protocols carefully.

Research overview

Outcome-by-outcome look at what the evidence actually supports for Retatrutide, including human vs. animal study counts and our editorial take on each.

Body weight reduction (obesity)

Clinical:StrongCommunity:Preliminary

Phase 2 data in adults with obesity show roughly 24% mean weight loss at 48 weeks at the highest dose — the largest reduction reported for any single agent at this stage.

3 human studies · 10 animal studies

Key findings & citations
  • Mean weight loss of approximately 24.2% at 12 mg over 48 weeks (Jastreboff 2023).
  • Dose-dependent response across 1, 4, 8, and 12 mg arms.
  • Weight loss had not plateaued by week 48 — Phase 3 will determine the asymptote.

Our take

Most effective weight-loss molecule we've ever seen in trial. Phase 3 (TRIUMPH) results will determine real-world rollout.

HbA1c reduction in T2D

Clinical:StrongCommunity:Preliminary

Phase 2 in adults with type 2 diabetes shows HbA1c reductions exceeding 2 percentage points at the higher doses, with most participants reaching <6.5%.

2 human studies · 6 animal studies

Key findings & citations
  • HbA1c reduction up to 2.16% at 12 mg over 36 weeks.
  • Greater than 75% of participants reached HbA1c <6.5% at the higher doses.
  • Fasting glucose and triglycerides also reduced significantly.

Our take

Expect retatrutide to compete directly with tirzepatide once approved. The triple-agonist mechanism gives it a metabolic edge on paper.

Hepatic steatosis (MASLD)

Clinical:ModerateCommunity:Preliminary

An MRI-PDFF sub-study of the obesity Phase 2 showed dramatic reductions in liver fat, including the majority of participants reaching normal liver fat thresholds.

1 human study · 4 animal studies

Key findings & citations
  • Liver fat reduced by approximately 82% from baseline at 12 mg.
  • Roughly 86% of participants achieved liver fat <5% at the higher doses.
  • Dedicated MASH histology trial is ongoing — fibrosis benefit not yet confirmed.

Our take

Steatosis effect is striking but not surprising given the GIP/glucagon agonism. Fibrosis evidence still pending.

What Retatrutide doesn't do

Claims that current evidence does not support. Worth knowing before you set expectations.

Top Retatrutide Vendors

#1 VendorNura Peptide25% OFFCOA Verified

$135.00 for 30mg ($4.50/mg) · Score: 10/10

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Dosing ProtocolWeight Loss

Educational reference only. Individual responses vary. Consult healthcare provider before use.

Vial Size
10 mg
Reconstitution
2 ml BAC water
Dose
0.5 mg (10 units on 1ml syringe)
Timing
AM
Frequency
3x per week
Duration
8 weeks on, 8 weeks off or until goal weight
Protocol Notes
Triple agonist (GIP/GLP-1/Glucagon). Investigational — follow research protocols carefully.

Why This Dosing Protocol

Why weekly? Extended half-life allows once-weekly injection like semaglutide and tirzepatide. Consistent weekly timing maintains steady blood levels.

Why very slow titration? The triple receptor activation requires even more careful titration than dual or single agonists. Start at 0.5mg and increase gradually over many weeks.
Full Dosing GuideReconstitution CalculatorCycle Cost Calculator
Popular Retatrutide Stacks

Pre-made bundles ranked by value. Cost per mg is based on the Retatrutide portion of each stack.

Top Retatrutide + Cagrilintide Blend Vendors

#1 VendorNura PeptideCOA Verified

$105.00 for 12.5mg/2.5mg ($8.08/mg) · Score: 10/10

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Reconstitution Calculator

Dilution math and unit conversions. Prefilled using a common vial size for this peptide.

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Storage & Handling

Storage at a glance

Proper storage temperatures, shelf life, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.

Powder: Freezer
1+ year at -20°C
Reconstituted: Fridge
4 weeks max at 2-8°C
View Complete Storage Guide

Handling specifics

Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.

Powder storage (very stable)
  • Freezer (-20°C): 1+ year
  • Refrigerator (2-8°C): 1-3 months
  • Room temperature: 2-3 weeks (emergency only)
Reconstituted storage (fragile)
  • MUST refrigerate at 2-8°C
  • 4-week maximum shelf life
  • NEVER freeze after reconstitution
  • Use bacteriostatic water for multi-dose
Molecular Structure

Retatrutide sequence

Click any residue to see its properties.

HydrophobicPolarAcidic (−)Basic (+)Special

Sequence-derived properties

Length
39 residues
Molecular weight
4207.6 Da
backbone only
Avg hydrophobicity
-0.37
Kyte–Doolittle scale

Residue classes

Hydrophobic: 13 (33%)Polar: 14 (36%)Acidic (−): 4 (10%)Basic (+): 1 (3%)Special: 7 (18%)

Net charge distribution

Positive1 (3%)
Neutral34 (87%)
Negative4 (10%)

Amino acid frequency

A×5S×5P×4Q×4D×3G×3Y×3F×2I×2L×2

Modifications

  • Aib residues
  • Lipid acylation for albumin binding

Sequence and properties provided for educational reference. Not for clinical dosing decisions.

  • Length: 39 amino acids
    (Multi-receptor agonist.)
  • Half-life: ~6 days
    (Allows weekly dosing.)
  • Mechanism: Triple agonist
    (GIP + GLP-1 + Glucagon.)
  • Primary Use: Weight loss
    (24% in Phase 2 trials.)
Key modifications
Optimized for balanced triple receptor activation
The glucagon component increases hepatic fat oxidation and energy expenditure, potentially explaining the unprecedented weight loss seen in clinical trials.
Key takeaway: Retatrutide showed the highest weight loss ever recorded for an obesity medication in Phase 2 trials. Currently in Phase 3 with potential FDA approval in 2025-2026.

FAQ

What makes retatrutide different from tirzepatide and semaglutide?

Retatrutide is a "triple agonist" — it activates GIP, GLP-1, AND glucagon receptors. Tirzepatide only activates GIP and GLP-1, while semaglutide only activates GLP-1. The added glucagon receptor activation increases energy expenditure (thermogenesis), potentially explaining the exceptional 24% weight loss seen in Phase 2 trials.

Is retatrutide FDA approved?

Not yet. Retatrutide completed Phase 2 trials with impressive results and is currently in Phase 3 trials. It's made by Eli Lilly (the same company behind tirzepatide). If Phase 3 confirms the Phase 2 results, FDA approval could come in 2025-2026.

What were the Phase 2 trial results?

In the 48-week Phase 2 trial, participants on the highest dose (12mg) lost an average of 24.2% of their body weight — the highest ever recorded for any obesity medication in clinical trials. Even the lower doses showed impressive results, with 12mg participants losing about 58 lbs on average.

What are the expected side effects?

Similar to other incretin medications: nausea, diarrhea, vomiting, and constipation, especially during dose escalation. The glucagon component may cause additional effects. Phase 2 showed manageable side effects, but full safety profile will be established in Phase 3 trials.

What does the glucagon receptor activation do?

Glucagon receptor activation increases energy expenditure by stimulating thermogenesis (heat production) and fat oxidation. It also promotes liver glucose release and may affect appetite through different pathways than GLP-1. This "calorie burning" effect adds to the appetite suppression from GIP/GLP-1 for enhanced weight loss.

How does retatrutide compare to tirzepatide for weight loss?

Phase 2 data suggests retatrutide produces even greater weight loss than tirzepatide (24% vs 20-22%). The added glucagon component appears to boost results. However, direct head-to-head trials haven't been conducted, and Phase 3 results will provide more definitive comparisons.

When will retatrutide be available?

Retatrutide is currently in Phase 3 clinical trials. If trials are successful and FDA approval is granted, it could potentially be available in 2026 or later. Some research chemical sources offer it now, but this is not the same as FDA-approved medication and carries additional risks.

What dosages are being tested for retatrutide?

A common research dosage is 0.5 mg (10 units on 1ml syringe) administered 3 times per week in the AM. Protocol: 8 weeks on, 8 weeks off or until goal weight is reached. Phase 2 clinical trials tested higher doses (1-12 mg weekly).

How long does reconstituted peptide last?

Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.

Is this peptide legal to purchase?

Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.

New to peptides?

Take our Peptide Match tool to find the best peptide for your goals. You can also read our Complete Guide to Peptides to learn the basics.

Scientific Sources

The following peer-reviewed studies and official resources provide additional scientific context for this peptide:

Retatrutide Research Articles

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Retatrutide + Cagrilintide Dosage: Stack Protocol

Both compounds slow GI transit through different pathways. Stack titration, split-site injection, and when to add cagrilintide to a retatrutide base.

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Retatrutide Dosage Chart: Doses, Units & Titration

Full retatrutide dosage chart with exact mg-to-units syringe conversions — 0.25mg, 0.5mg and 1mg from a 10mg vial — plus community starting doses.

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Where to Buy Retatrutide: Price & Vendor Guide

One vendor sells 60mg vials at half the per-mg cost of 12mg — but COA matters more than price. Vial sizes, cost per week, and vendor scores.

Compare Retatrutide to alternatives

Side-by-side mechanism, dose, half-life, and vendor pricing.

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