Retatrutide weight-management protocol
Retatrutide is a once-weekly GLP-1, GIP and glucagon triple agonist. This protocol covers the 16-week ramp from 2 mg and the long hold at the target dose. Doses, units and the trial table are on the Retatrutide page.
16-week ramp, then a 64-week hold (80 weeks in TRIUMPH-1 and -2)
Why this protocol
Retatrutide hits three receptors at once: GLP-1 (curbs appetite, boosts insulin), GIP and glucagon (studied to raise energy expenditure). In the Phase 3 TRIUMPH-1 trial, body weight fell 17.6%, 23.7% and 25.0% over 80 weeks on the 4, 9 and 12 mg targets, against 3.9% on placebo.
Every arm in TRIUMPH-1 to -4 started at 2 mg and moved up one step every 4 weeks to its target, and people could step back a dose for gut side effects. In Phase 2, a 2 mg start partly reduced gut side effects compared with a 4 mg start.
The regimen
Retatrutide
Triple agonist (GLP-1/GIP/glucagon)- Dose
- 2 mg a week, stepping up to 4, 9 or 12 mg
- Schedule
- Once weekly · subcutaneous
- Timing
- One consistent day each week; time of day is flexible
Reconstitution calculator
Reconstitution calculator
Calculated for a 1 mL U-100 insulin syringe (100 units/mL).
Units per dose
40 units
Draw this many units on a U-100 syringe
Each unit holds 100 mcg
- Volume per dose
- 0.4 mL
- Doses per vial
- 5
- Concentration
- 10 mg/mL
One vial lasts
- Daily
- 5 days
- Every other day
- 10 days
- 5×/week
- 7 days
- Large draw (40 units). That's normal for mg doses. To check it, multiply the units by what each unit holds. You should get your dose.
Research use only. Not for human consumption. Outputs are reference values based on research literature. Verify all measurements independently.
Cycle & schedule
- Ramp (up to 16 weeks)People start at 2 mg once a week and move up one step every 4 weeks (2, 4, 6, 9, then 12 mg), stopping at their target. Many people eat light, low-fat meals on step-up days. When gut side effects get hard, the trials let people step back a dose, then climb again.
- Hold at the target (to week 80)After the last step, the dose stays the same. TRIUMPH-1 and TRIUMPH-2 ran 80 weeks in all, 16 weeks of escalation and then 64 weeks of maintenance.
- Diet and activity alongsideTRIUMPH paired the drug with counseling on what to eat (not calorie restriction) and at least 150 minutes of moderate activity a week.
Studies behind this protocol
- PMID 41090431Giblin et al., Diabetes Obes Metab 2026 (TRIUMPH Phase 3 design; 2 mg start, 4-week dose steps, 80-week treatment in TRIUMPH-1 to -3)
- PMID 42814954Jastreboff et al., N Engl J Med 2026 (TRIUMPH-1, Phase 3 obesity trial, 80 weeks)
- PMID 37366315Jastreboff et al., N Engl J Med 2023 (Phase 2 obesity trial)
Research use only · Not medical advice · Updated 2026-10-04