GLP-1 & incretin

Retatrutide

Controlled trials

Triple GIP/GLP-1/glucagon receptor agonist.

SubQIntermediateNot approved anywherefat lossappetite controlmetabolic health

Also known as LY3437943 · Reta · Triple-G

At a glance

Dose summary

Typical dose4 mg

Range500 mcg–12 mg

FrequencyWeekly

Half-life~6 days

ScheduleOnce a week

Cycle lengthNot cycled

RouteSubQ

Experience levelIntermediate

Evidence gradeControlled trials

ApprovalNot approved anywhere

Where the dose comes fromPublished trial dosing

Reconstitution

What to draw, at the usual vial

A 20 mg vial reconstituted with 2 mL of bacteriostatic water gives 10.00 mg/mL. A typical 4 mg dose is 0.400 mL — pull the plunger to 40 units on a U-100 syringe.

Concentration10.00 mg/mL

Draw volume0.400 mL

U-100 units40 units

Doses per vial5

Same dose, other vial sizes

Vial	Water	Concentration	Draw	Units	Doses
5 mg	2 mL	2.50 mg/mL	1.600 mL	160 units	1
10 mg	2 mL	5.00 mg/mL	0.800 mL	80 units	2
12 mg	2 mL	6.00 mg/mL	0.667 mL	66.7 units	3
20 mg	2 mL	10.00 mg/mL	0.400 mL	40 units	5

The highlighted row is the one quoted above: the smallest listed vial that holds at least four typical doses. Change any of it — a different vial, more or less water, a different dose — on the reconstitution calculator, which draws the syringe to true U-100 graduations.

Titration

Step-up ladder

This compound is escalated rather than held flat. Each step is a fixed number of weeks before the next increase — the side effects cluster in the days after a step, not at the top of the ladder.

Step	Weeks	Dose	Note
1	1–2	500 mcg	starting dose
2	3–4	1 mg	—
3	5–8	2 mg	—
4	9–12	4 mg	—
5	13–16	8 mg	—
6	17–20	12 mg	trial maximum

Full ladder: 20 weeks from the starting dose to the top step.

Mechanism & evidence

What it is, and what is known

Triple GIP/GLP-1/glucagon receptor agonist. Phase 2 randomized human trials in obesity and type 2 diabetes used 1, 4, 8 and 12 mg once weekly with 4-week step-ups, and phase 3 is ongoing. It is investigational and NOT approved by any regulator, so there is no approved label, no long-term safety data, and no pharmacy-grade product. The glucagon arm adds a heart-rate signal that semaglutide and tirzepatide do not have to the same degree.

The caveat

Phase 2 complete and phase 3 ongoing. Investigational — no approved label, no long-term safety data, no pharmacy-grade product.

Tolerability

Reported side effects

Nausea and vomiting, worst in the weeks after a dose increase
Diarrhoea or constipation
Increased heart rate, seen dose-dependently in trials
Loss of appetite severe enough to under-eat protein
Fatigue and injection site reactions

Hard stops

Do not use this if

Pregnancy, possible pregnancy, or breastfeeding
Personal or family history of medullary thyroid carcinoma, or MEN2
History of pancreatitis
Existing thyroid disease

These are flags, not a screening. They do not replace a conversation with a clinician who knows your history.

Handling

Storage

Sealed powder, refrigerated24 months

After reconstitution, refrigerated56 days

Keep it cold, keep it dark, and label the vial with the date you mixed it. Discard anything cloudy or past the window above.

Where it shows up

Protocols using this compound

Retatrutide + KLOW2 mg · once a weekA fat-loss block that pairs weekly retatrutide with the daily KLOW healing blend. The logic people give is that aggressive weight loss is catabolic and hard on skin, joints and gut, and KLOW is meant to offset that. Retatrutide does the fat loss; KLOW does nothing for it.Retatrutide + GH Pulse2 mg · once a weekWeekly retatrutide for the fat loss, plus the standard nightly GHRH + GHRP pulse (CJC-1295 without DAC and ipamorelin) bolted on. The stated reason is preserving lean mass through an aggressive incretin cut. Read the evidence note before you buy that reason - the lean-mass problem is real and measured, but this specific fix is not.

References

Sources

Educational information only, not medical advice. Talk to a licensed clinician before starting, changing, or stopping anything.