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Educational comparison - not medical advice. This page compares two compounds for informational purposes. Neither is recommended as treatment. Any protocol decision is a conversation with your licensed healthcare provider.
Home/Peptides/Tirzepatide vs Retatrutide
HEAD-TO-HEAD COMPARISON

Tirzepatide vs Retatrutide

Users tracking the Lilly incretin pipeline and comparing approved vs investigational options.

QUICK ANSWER

Tirzepatide is FDA-approved and commercially available (Mounjaro/Zepbound). Retatrutide is Eli Lilly's investigational triple-agonist (GLP-1 + GIP + glucagon) currently in Phase 3 - ~24% mean weight reduction in Phase 2 at highest dose, the largest single-compound effect published. Key specs: Tirzepatide (GLP-1, ~5 days, Subcutaneous (weekly)) vs Retatrutide (GLP-1, ~6 days, Subcutaneous (weekly)).

OPTION A
Tirzepatide
Tirzepatide (Mounjaro / Zepbound)
FDA-approved dual GIP/GLP-1 receptor agonist with superior weight loss efficacy vs semaglutide in head-to-head data.
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OPTION B
Retatrutide
Retatrutide (LY-3437943)
Investigational triple agonist (GLP-1 / GIP / glucagon) with the largest weight-loss effect of any compound yet reported in its class.
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THE CORE DIFFERENCE

Tirzepatide is FDA-approved and commercially available (Mounjaro/Zepbound). Retatrutide is Eli Lilly's investigational triple-agonist (GLP-1 + GIP + glucagon) currently in Phase 3 - ~24% mean weight reduction in Phase 2 at highest dose, the largest single-compound effect published. Retatrutide is not FDA-approved and requires discussion with a clinician; most current access is research-chemical. Expected FDA action 2026-2027.

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FEATURE COMPARISON
Tirzepatide
Retatrutide
Full name
Tirzepatide (Mounjaro / Zepbound)
Retatrutide (LY-3437943)
Category
GLP-1
GLP-1
FDA status
FDA-approved as Mounjaro (T2D) and Zepbound (chronic weight management).
Not FDA-approved. In Phase 3 trials. Expected FDA filing ~2026.
Half-life
~5 days
~6 days
Typical dosing
2.5 → 15 mg weekly (titrated over 20+ weeks)
1 → 12 mg weekly (research dosing - not FDA-approved)
Route
Subcutaneous (weekly)
Subcutaneous (weekly)
Classification
Dual GIP + GLP-1 receptor agonist
Triple agonist (GIP + GLP-1 + glucagon receptor)
BIOMARKERS COMMONLY TRACKED
On Tirzepatide
  • • HbA1c
  • • Fasting glucose
  • • ApoB
  • • Triglycerides
  • • LFTs
  • • Weight
On Retatrutide
  • • HbA1c
  • • ApoB
  • • Fasting glucose
  • • LFTs (ALT, AST)
  • • Heart rate
  • • Weight
CALCULATOR
Tirzepatide reconstitution →
CALCULATOR
Retatrutide reconstitution →
CONDITIONS USERS RESEARCH THESE FOR
Informational only - neither compound is presented as a treatment for any condition. These are contexts in which users research these compounds and discuss them with their licensed provider.
METABOLIC
Insulin Resistance
The metabolic pattern where cells become less responsive to insulin - trackable through specific biomarkers before it becomes diabetes.
METABOLIC
Metabolic Syndrome
The constellation of cardiovascular + metabolic risk factors - diagnosed clinically, tracked via a specific marker cluster.
CARDIOVASCULAR
Elevated ApoB (Cardiovascular Risk)
When the atherogenic particle count is elevated - the single most accurate cardiovascular risk lab marker.
METABOLIC
Elevated Visceral Fat
The metabolically-active abdominal fat linked to cardiovascular + insulin-resistance risk. Hard to see; visible in labs.
RELATED COMPARISONS
Semaglutide vs Tirzepatide
Semaglutide vs Retatrutide
FREQUENTLY ASKED QUESTIONS

What is the difference between Tirzepatide and Retatrutide?

Tirzepatide is FDA-approved and commercially available (Mounjaro/Zepbound). Retatrutide is Eli Lilly's investigational triple-agonist (GLP-1 + GIP + glucagon) currently in Phase 3 - ~24% mean weight reduction in Phase 2 at highest dose, the largest single-compound effect published. Retatrutide is not FDA-approved and requires discussion with a clinician; most current access is research-chemical. Expected FDA action 2026-2027.

Who typically researches Tirzepatide vs Retatrutide?

Users tracking the Lilly incretin pipeline and comparing approved vs investigational options. Tirzepatide (GLP-1, ~5 days, Subcutaneous (weekly)) and Retatrutide (GLP-1, ~6 days, Subcutaneous (weekly)) differ in mechanism and dosing cadence - the right choice depends on protocol goals, biomarker baseline, and provider guidance. MyProtocolStack lets you log doses and lab values for both side-by-side if you're cycling between them.

What blood markers do users track on Tirzepatide or Retatrutide?

Biomarkers commonly tracked across Tirzepatide and Retatrutide protocols include HbA1c, Fasting glucose, ApoB, Triglycerides, LFTs, Weight, LFTs (ALT, AST), Heart rate. Establishing a baseline before starting and re-drawing at consistent intervals lets you measure each compound's effect against your own reference point - generic lab ranges are less informative than your personal trend over time. MyProtocolStack tracks these biomarkers in the context of whichever compound you're currently running.

Whichever you're tracking, we built the dashboard for it.

Log doses, upload labs, watch the biomarkers trend. StackAI reads your panel in context of what you're actually running.

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Informational comparison only - not medical advice. Research-stage compounds discussed are not FDA-approved unless specifically noted. Any protocol decision should be made with a licensed healthcare provider.