Protocol
Weight Loss and Metabolic
Retatrutide Titration Protocol [2026]
Triple receptor agonism (GLP-1, GIP, glucagon) titrated conservatively given the novel mechanism and potency.
Compounds
Retatrutide
Dose: 1 mg
Freq: Once weekly
Recon: 4mg + 2mL BAC
Conc: 2 mg/mL
Draw: 5 units (U-100)
Calculate Retatrutide dose
Protocol Phases
Initiation
Weeks 1 to 4
1 mg subcutaneous once weekly. Lower starting dose than other GLP-1 agents given the added glucagon component.
Escalation 1
Weeks 5 to 8
2 mg once weekly. Monitor heart rate, which can increase with glucagon receptor activation.
Escalation 2
Weeks 9 to 12
4 mg once weekly.
Escalation 3
Weeks 13 to 20
8 mg once weekly. Phase III trials used 8 mg and 12 mg as target doses.
FAQ
What makes retatrutide different from tirzepatide?
Retatrutide adds glucagon receptor agonism on top of GLP-1 and GIP. The glucagon component increases energy expenditure and lipolysis beyond what GLP-1 alone achieves. This triple mechanism is associated with greater weight reduction in trials than dual agonists.
Is retatrutide approved for research use?
Retatrutide is in Phase III clinical trials as of 2026. It is not FDA approved. It is available as a research compound through peptide research suppliers.
Does retatrutide affect heart rate?
Yes. The glucagon receptor component is associated with modest heart rate increases, typically 2 to 4 BPM, similar to what is seen with other GLP-1 agents but potentially amplified. This is worth monitoring, particularly during escalation phases.
How do I calculate retatrutide draw volume?
For a 4 mg vial reconstituted in 2 mL BAC water: 2 mg/mL. For a 2 mg dose: 2 divided by 2 = 1.0 mL = the 100 unit line on a U-100 syringe. Use the ASCEND calculator for any other concentration.
Research Notes
- Start at 1 mg. This compound is more potent per mg than semaglutide or tirzepatide.
- Monitor resting heart rate during escalation.
- Hold each step for 4 weeks minimum before advancing.
Related Protocols
For research use only. Not medical advice.