Side-by-Side Comparison · 2026

Retatrutide vs Tirzepatide

Retatrutide vs Tirzepatide — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Retatrutide
Metabolic / Triple Incretin Agonist

Retatrutide is a first-in-class GLP-1/GIP/glucagon triple receptor agonist by Eli Lilly. Phase 2 trials demonstrated up to 24.2% weight loss at 48 weeks - surpassing all previously approved agents. Phase 3 trials actively enrolling for obesity and type 2 diabetes....

Calculate Retatrutide dose →
Tirzepatide
Metabolic / Dual Incretin Agonist

Tirzepatide is a first-in-class dual GIP/GLP-1 receptor agonist (twincretin) developed by Eli Lilly. SURMOUNT trials demonstrated up to 22.5% mean weight loss - the greatest pharmacological weight reduction ever shown in a clinical program. Approved as Mounjaro for type 2 diabete...

Calculate Tirzepatide dose →
Key Parameters
Parameter Retatrutide Tirzepatide
Category Metabolic / Triple Incretin Agonist Metabolic / Dual Incretin Agonist
Research Phase 3 Clinical Trials FDA Approved
Half-Life ~6 days ~120 hours (5 days)
Typical Dose 1-24 mg/week (Phase 2); Phase 3 doses TBD 2.5-15 mg/week
Frequency Once weekly Once weekly
Route Subcutaneous injection Subcutaneous injection
FDA Status Phase 3 (obesity, T2D); not yet approved Approved (T2D 2022, obesity 2023)

Calculate doses for both

Use ASCEND's free reconstitution calculator to get exact syringe draw amounts for your vial.

Calculate Retatrutide Calculate Tirzepatide
Frequently Asked Questions
What is the difference between Retatrutide and Tirzepatide?
Retatrutide: Retatrutide is a first-in-class GLP-1/GIP/glucagon triple receptor agonist by Eli Lilly. Phase 2 trials demonstrated up to 24.2% weight loss at 48 weeks - surpassing all previously approved agents. Ph... Tirzepatide: Tirzepatide is a first-in-class dual GIP/GLP-1 receptor agonist (twincretin) developed by Eli Lilly. SURMOUNT trials demonstrated up to 22.5% mean weight loss - the greatest pharmacological weight red...
Which has a longer half-life, Retatrutide or Tirzepatide?
Retatrutide half-life: ~6 days. Tirzepatide half-life: ~120 hours (5 days).
Can you stack Retatrutide and Tirzepatide?
Retatrutide and Tirzepatide are sometimes used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.