Retatrutide

GLP-1 / GIP / Glucagon triple agonist for substantial weight loss and metabolic improvement.

Quick Reference

Dose: 1–6 mg (most common practical range)
Frequency / schedule: Once weekly
Route: Subcutaneous
Timing: Any consistent day of the week (morning or evening both work)
Fasting: Not required — can be taken with or without food
Cycle: Ongoing / multi-month
Time off: Weight regain expected on stop
Common vial strengths: 5 mg, 10 mg, 12 mg research vials

How this works

Retatrutide is a synthetic triple agonist that activates GLP-1, GIP, and glucagon receptors simultaneously. - Semaglutide = GLP-1 only - Tirzepatide = GLP-1 + GIP - Retatrutide = GLP-1 + GIP + Glucagon In plain English: - GLP-1 kills appetite - GIP helps handle carbs / blood sugar - Glucagon turns on the fat-burning switch The glucagon component tells the body to use fat for energy instead of storing it, which is why metabolism feels hotter and leaning accelerates once the dose is ramped. Half-life is ~6 days, supporting once-weekly dosing.

Benefits + side effects

Potential Benefits

Highest weight-loss percentages among current incretin agonists
Strong appetite suppression
Increased resting energy expenditure and hepatic fat oxidation
Improved glycemic control and liver fat

Side Effects

Dose-related GI effects (nausea, diarrhea, vomiting, constipation)
Transient heart-rate increase
Injection-site reactions

Dosing / Protocol

Reference Protocol

Phase / week	Dose	Frequency
Week 1	1 mg once weekly	Start low. Even 0.5 mg if lighter.
Week 2	2 mg weekly	Step it up.
Week 3	3 mg weekly	Appetite usually crushed here.
Week 4	4 mg weekly	Metabolism really kicks on.
Week 5	5 mg if plateau (wait 10 days)	Don’t rush.
Week 6	6 mg max	Most people don’t need more.

Timing + Fasting Notes

- Inject on the same day each week at a convenient consistent time. - Food does not meaningfully affect absorption. - Many prefer evening dosing so any mild nausea occurs while sleeping.

Reconstitution

Common vial strengths5 mg, 10 mg, 12 mg research vials

Approved preparation example
10 mg vial + 2 mL BAC water = 5 mg/mL. Adjust volume to make units easy on a U-100 syringe.

Practical Reference

Storage: Lyophilized frozen or refrigerated; reconstituted refrigerated, use within 28 days
Route / injection context: Subcutaneous
Bloodwork / markers: Weight, HbA1c, fasting glucose, lipids, liver enzymes, resting heart rate
Common vial strengths: 5 mg, 10 mg, 12 mg research vials
Cycle / time off: Ongoing / multi-month · Weight regain expected on stop
Practical notes: Slow titration is critical. Stay at the lowest effective dose. Research use only.

References

Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 TrialNew England Journal of Medicine · 2023 · DOI 10.1056/NEJMoa2301972

CLINICAL TRIAL02

Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetesThe Lancet · 2023 · DOI 10.1016/S0140-6736(23)01053-X

CLINICAL TRIAL03

Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver diseaseNature Medicine · 2024 · DOI 10.1038/s41591-024-03018-2

CLINICAL TRIAL04

TRIUMPH-1 Phase 3 topline resultsEli Lilly and Company · 2026

SPONSOR UPDATE05

TRIUMPH-2 and TRIUMPH-3 Phase 3 topline results and planned regulatory submissionEli Lilly and Company · 2026

SPONSOR UPDATE06

What to know about retatrutideEli Lilly and Company · 2026

REGULATORY

Dataset reference context: Phase 2 NEJM data + community titration consensus

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