GLP's ⏱ Half-life: Approximately 6 days, supporting once-weekly subcutaneous administration. Phase 3

Retatrutide

Retatrutide (Triple Incretin Agonist GIP/GLP-1/Glucagon)

Updated March 15, 2026
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Evidence at a Glance

Regulatory statusPhase 3
Eli Lilly GIP/GLP-1/glucagon triple agonist; multiple active Phase 3 trials (TRIUMPH, TRANSCEND), not yet approved.
Human evidenceExtensive
Animal evidenceExtensive

An investigational triple-hormone-receptor agonist in ongoing Phase 3 obesity and type 2 diabetes trials with large reported weight-loss effects, but no regulatory approval yet.

What the research does not support

  • It is not FDA-approved and cannot be legally sold or prescribed as a finished medicine.
  • 'GLP-3' is a marketing nickname, not a real receptor class; it is a GIP/GLP-1/glucagon triple agonist.
  • Its long-term safety is not yet established, as pivotal trials are still ongoing.
  • The headline weight-loss numbers came from monitored clinical trials with lifestyle support, not from self-dosing research-grade powder.
Half-Life
Approximately 6 days, supporting once-weekly subcutaneous administration.
Mol. Weight
~4600 g/mol

What is Retatrutide?

Retatrutide represents the cutting edge of incretin-based metabolic research as the first triple-acting agonist targeting GIP, GLP-1, and glucagon receptors simultaneously. Early clinical data has generated significant excitement in metabolic research due to the magnitude of observed effects.

Research Applications

Currently under investigation in the TRIUMPH Phase 3 program for metabolic research, with additional trials examining liver fat reduction and cardiovascular outcomes.

Dosage Information (Research Use)

Phase 2 trial utilized a titration protocol: starting at 0.5mg weekly, escalating through 1, 2, 4, 8, to 12 mg over 24-48 weeks. Research use only.

Reconstitution & Handling

Standard BAC water reconstitution. Handle with care and protect from light.

Half-Life & Pharmacokinetics

Approximately 6 days, supporting once-weekly subcutaneous administration.

Reported Observations in Literature

Phase 2 data showed dose-dependent GI effects similar to GLP-1 agonists, with generally manageable severity using titration. Nausea, diarrhea, and vomiting were most common.

Key Research References

  • Jastreboff AM, et al. “Triple-Hormone-Receptor Agonist Retatrutide for Obesity.” N Engl J Med. 2023

How Retatrutide Works

Retatrutide (LY3437943) is a triple-acting receptor agonist that simultaneously activates GIP, GLP-1, and glucagon receptors. The addition of glucagon receptor agonism — which increases energy expenditure via hepatic lipid oxidation and thermogenesis — creates a three-pronged metabolic approach. The glucagon component also promotes hepatic fat mobilization, potentially addressing fatty liver pathology more directly than dual agonists.

Research Findings

Phase 2 trial data showed the highest weight reduction observed in any clinical trial to date at the 12mg dose level. Phase 3 TRIUMPH program is ongoing. Liver fat reduction data is particularly notable, with near-complete resolution of hepatic steatosis in some trial participants.

Dosage & Administration

Phase 2 trial utilized a titration protocol: starting at 0.5mg weekly, escalating through 1, 2, 4, 8, to 12 mg over 24-48 weeks. Research use only.

Safety & Side Effects

Phase 2 data showed dose-dependent GI effects similar to GLP-1 agonists, with generally manageable severity using titration. Nausea, diarrhea, and vomiting were most common.

Important: All safety information is derived from published research, primarily animal studies. No controlled human clinical trial data exists unless explicitly noted. This compound is sold for research purposes only.

Quick Facts

Sequence Modified 39-amino acid peptide with fatty acid acylation
Molecular Weight ~4600 g/mol
Half-Life Approximately 6 days, supporting once-weekly subcutaneous administration.
Available Sizes 5mg, 10mg
Storage Lyophilized: -20°C. Reconstituted: 2-8°C, use within 21 days.

Key Research References

  • Jastreboff AM, et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity." N Engl J Med. 2023

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