GLP3-R + GLP2-T Blend is a compounded research product combining retatrutide (triple GIP/GLP-1/glucagon agonist, Phase III development) with tirzepatide (dual GIP/GLP-1 agonist, FDA-approved as Mounjaro/Zepbound). Both are long-acting once-weekly peptides developed for type 2 diabetes and obesity. There are no human clinical trials of the combination, and mechanistically the two agents produce overlapping rather than additive activation of the GIP and GLP-1 receptor axes. The blend exists only as a self-experimentation product in the research-chemical market with no controlled efficacy data.
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Formulation caution
Retatrutide + Tirzepatide. Both already provide GLP-1 receptor agonism — mechanistically redundant. No legitimate sponsor would run this combination in clinical trials. Surface a strong caution on the detail page.
What's in this blend
Weight Loss
Retatrutide (LY3437943) is a once-weekly subcutaneous triple agonist of the GIP, GLP-1, and glucagon receptors developed by Eli Lilly.
Weight Loss
Tirzepatide (LY3298176) is a synthetic 39-amino-acid dual agonist of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, developed by Eli Lilly.
Vendor data
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Browse all vendorsMechanism of action
Tirzepatide is a balanced dual agonist of the GIP and GLP-1 receptors; retatrutide adds glucagon receptor agonism on top of GIP/GLP-1 activation. Both peptides drive appetite suppression, slowed gastric emptying, and glucose-dependent insulin secretion via the incretin axis.
Pharmacokinetic properties
Half-life
Retatrutide ~6 days; tirzepatide ~5 days subcutaneous (both once-weekly).
Routes
subcutaneous
Bioavailability
Both lipidated peptides; not orally bioavailable. Co-administration does not alter individual PK.
Amino-acid sequence
Use & research dosing
No clinical trial of this specific combination exists in any registry. Self-experimentation protocols vary widely: some users use one agent as 'maintenance' while titrating the other, others split dosing across the week. Standard monotherapy ceilings are retatrutide 8-12 mg weekly and tirzepatide 15 mg weekly, and combining them would exceed the additive safety margin established in monotherapy trials. Not FDA-approved for combination use and not in any registered trial. Research framing only.
Research-use framing only. SavePeptides sells nothing for human consumption. Doses above reflect reported research / self-experimentation ranges, not clinical recommendations.
Current state: Mechanistically questionable — stacking two GIP/GLP-1 agonists produces overlapping signaling. The only marginally rational use case is bridging between titration schedules. No clinical trial supports the combination, and the evidence base for each component individually is robust enough that monotherapy at appropriate dose is generally preferred. Compounded product quality varies.
— SavePeptides editorial desk · last updated 2026-05-25
Cautions & contraindications
Facts verified
2026-05-25
Confidence
low
What this means
Vendor data coming soon
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