Question 1

What is retatrutide?

Accepted Answer

Retatrutide (LY3437943) is an investigational once-weekly injectable triple agonist targeting GIP, GLP-1, and glucagon receptors, developed by Eli Lilly. As of 2026 it is not approved by the FDA, the EMA, or any other regulator for any indication. Access is currently through compounding pharmacies under physician supervision. Sources: ClinicalTrials.gov TRIUMPH program (TRIUMPH-1 NCT05929066); Jastreboff et al. NEJM 2023 (PMID 37366315); TRIUMPH Phase 3 design (PMID 41090431).

Question 2

What is the Phase 3 TRIUMPH titration ladder?

Accepted Answer

The Phase 3 TRIUMPH ladder is 2 mg, then 4 mg, then 6 mg, then 9 mg, then 12 mg, advancing one step every 4 weeks: 2 mg for weeks 1-4, 4 mg for weeks 5-8, 6 mg for weeks 9-12, 9 mg for weeks 13-16, then 12 mg weekly as maintenance from week 17 onward. Target and maintenance doses formally evaluated were 4 mg, 9 mg, and 12 mg. This replaces the older Phase 2 1/2/4/8/12 mg escalation, which is superseded for dosing purposes.

Question 3

What is the extended-interval (conservative) schedule?

Accepted Answer

The conservative schedule uses the same 2/4/6/9/12 mg Phase 3 ladder but holds each step for 6 weeks instead of 4 (weeks 1-6 at 2 mg, 7-12 at 4 mg, 13-18 at 6 mg, 19-24 at 9 mg, then 12 mg from week 25). This is not a trial-defined schedule; it is a clinical extrapolation for patients who experience significant GI side effects at the standard pace.

Question 4

Is retatrutide FDA-approved?

Accepted Answer

No. As of 2026, retatrutide has no FDA-approved indication and is not approved by the EMA or any other regulator. Compounded retatrutide is available through certain pharmacies but its use is off-label and requires physician oversight.

Question 5

How do I calculate mL per dose for compounded retatrutide?

Accepted Answer

Divide the target dose in mg by the vial concentration in mg/mL. For example, at 10 mg/mL, a 4 mg dose = 0.4 mL = 40 units on a U-100 syringe. This calculator performs that math automatically for every step in the schedule.

Question 6

What concentration do compounded retatrutide vials come in?

Accepted Answer

Concentration varies by compounding pharmacy. Common concentrations are 5 mg/mL, 10 mg/mL, and 20 mg/mL. Always verify the concentration listed on your specific vial before drawing a dose.

Week	Target dose	mL per draw	U-100 units
Weeks 1-4	2 mg	0.2 mL	20 units
Weeks 5-8	4 mg	0.4 mL	40 units
Weeks 9-12	6 mg	0.6 mL	60 units
Weeks 13-16	9 mg	0.9 mL	90 units
Week 17+ (maintenance)	12 mg	1.2 mL	120 units

Week	Target dose	mL per draw	U-100 units
Weeks 1-4	2 mg	0.2 mL	20 units
Weeks 5-8	4 mg	0.4 mL	40 units
Weeks 9-12	6 mg	0.6 mL	60 units
Weeks 13-16	9 mg	0.9 mL	90 units
Week 17+ (maintenance)	12 mg	1.2 mL	120 units

Retatrutide Titration Calculator