GLP-1/GIP/glucagon triple receptor agonist · studied for weight loss, type 2 diabetes blood sugar, fatty liver, knee osteoarthritis with obesity

Retatrutide dosage

Retatrutide is Eli Lilly's triple agonist, still in phase 3 and not approved anywhere. The phase 2 trial in NEJM tested 1, 4, 8 and 12 mg once weekly for 48 weeks and saw 8.7% to 24.2% weight loss against 2.1% on placebo. Trial arms that started at 2 mg and climbed every 4 weeks had fewer stomach problems than arms that started high. People using research vials mostly copy that: start at 0.5 to 2 mg, step up every 4 weeks, and settle between 4 and 8 mg.

By the Peptide Calculations editors · Updated 2026-10-19

1 mg to 12 mgper week

Basis: clinical trial (phase 2, Jastreboff et al., NEJM 2023). 4 mg, 8 mg and 12 mg arms started at 2 mg or 4 mg and escalated every 4 weeks; 48 week weight change was 8.7% at 1 mg and 24.2% at 12 mg

How often: once weekly
When: same day each week, any time of day
How long: continuous while in use; phase 2 ran 48 weeks, phase 3 (TRIUMPH) runs 80 weeks
Route: subcutaneous, abdomen or thigh; rotate sites
Storage: lyophilized: fridge or freezer; reconstituted: fridge, commonly used within 4 weeks (commonly reported)

Dose ranges by source

Range	Per	Basis	Note
1 mg to 12 mg	week	clinical trial (phase 2, Jastreboff et al., NEJM 2023)	4 mg, 8 mg and 12 mg arms started at 2 mg or 4 mg and escalated every 4 weeks; 48 week weight change was 8.7% at 1 mg and 24.2% at 12 mg
0.5 mg to 8 mg	week	commonly reported	self-reported users start at 0.5 to 2 mg, climb every 4 weeks, and most hold at 4 to 8 mg; 12 mg is rarely reported outside trials

Titration schedule

Step up on this schedule; stay a step longer if side effects are rough.

Weeks	Dose
1-4	0.5 mg to 1 mg (trial arms started at 1 or 2 mg)
5-8	2 mg
9-12	4 mg
13-16	6 mg
17 onward	8 mg; 12 mg was the top trial dose

Retatrutide dose to units chart

10 mg vial + 2 mL bacteriostatic water = 5 mg/mL (50 mcg per unit on a U-100 insulin syringe). 10 mg + 2 mL = 5 mg/mL, so 1 mg = 0.2 mL = 20 units; 2 mg = 40 units, 4 mg = 80 units. A 5 mg vial with 1 mL gives the same 5 mg/mL.

Dose	mL	Units (U-100)	Doses per vial
500 mcg	0.1	10	20
1 mg	0.2	20	10
2 mg	0.4	40	5
2.5 mg	0.5	50	4
4 mg	0.8	80	2
5 mg	1	100	2
6 mg	1.2	120	1
8 mg	1.6	160	1
10 mg	2	200	1
12 mg	2.4	240	0

Different vial or water? Full 10 mg + 2 mL table or set your own numbers below.

Commonly stacked with

Cagrilintide 0.3 mg to 4.5 mg

Side effects

nausea
vomiting
diarrhea
constipation
reduced appetite
heart rate increase (peaked at 24 weeks in the trial)
skin tingling or sensitivity
fatigue

Before you start. There is no approved dose and no label; every number above comes from a 48 week trial of 338 people or from self-reports. It acts on the glucagon receptor too, so heart rate went up in a dose-dependent way and the same thyroid, pancreatitis and gallbladder cautions as the other GLP-1 drugs apply. Starting at 1 mg or less and moving every 4 weeks is what kept trial dropouts down. Not medical advice; talk to a clinician.

Retatrutide dosage questions

Retatrutide dosage chart?

Trial doses were 1, 4, 8 and 12 mg once weekly, with the higher arms starting at 2 mg and stepping up every 4 weeks. The commonly reported self-dosing ladder is 0.5 to 1 mg for 4 weeks, 2 mg, 4 mg, 6 mg, then 8 mg. On a 10 mg vial in 2 mL that is 10 to 20 units, 40, 80, 120 (two draws) and 160 units.

How much retatrutide should I start with?

The trial arms with the fewest stomach problems started at 2 mg or lower. Most self-reported users start at 0.5 mg to 1 mg and hold 4 weeks. Starting at 4 mg is where the trial saw the worst early nausea.

How much weight do you lose on retatrutide?

In the NEJM phase 2 trial, 48 week weight loss averaged 8.7% at 1 mg, 17.1% at 4 mg, 22.8% at 8 mg and 24.2% at 12 mg, against 2.1% on placebo. Those are averages in a supervised trial with diet counseling, not a promise.

Is retatrutide approved?

No. It is in phase 3 trials and has no FDA label, so there is no official dose. Anything sold today is research material, and the only human dose data is the trials above.

Sources

Brands we recommend for Retatrutide. We are independent and have no affiliation with any brand: no affiliate links, no referral codes, no paid placements. These are the suppliers whose testing and certificates hold up when we check them.

Licensed Peptides two accredited labs on every lot, certificates public, card and Apple Pay checkout
Core Peptides long track record, public certificates, wide catalog
Ascension Peptides public third-party testing, clear pricing

This page is an educational summary of published labels, trials and commonly reported use. It is not medical advice and does not replace a clinician.