What doses of retatrutide were used in the research?

The Phase 2 obesity trial (Jastreboff et al., NEJM 2023) tested subcutaneous retatrutide in cohorts targeting 1, 4, 8 and 12 mg once weekly. The higher-dose arms began at 2 mg and escalated in stepwise fashion. These figures are reproduced as a laboratory research reference; they are not a human dosing protocol or medical advice.

How is retatrutide titrated in the literature?

The trials used a slow stepwise escalation — commonly 2 mg, then 4 mg, then 8 mg, then up to 12 mg — holding each step for about four weeks before moving up. The gradual ramp manages the gastrointestinal tolerability characteristic of GLP-1/GIP/glucagon agonists. Four weeks per step also roughly matches the time to approach steady-state given the ~6-day half-life.

How do I reconstitute a 10mg retatrutide vial?

Add bacteriostatic water to the lyophilized powder; the concentration depends on the volume. Adding 2 mL gives 5 mg/mL, so 0.04 mL on a U-100 insulin syringe equals 2 mg, 0.08 mL equals 4 mg, and 0.16 mL equals 8 mg. Adding 1 mL gives 10 mg/mL and halves those draw volumes. Always verify against the reconstitution calculator before any in-vitro work.

What is retatrutide's half-life?

Retatrutide's terminal half-life is reported at roughly 6 days (about 144 hours). That long half-life is why once-weekly administration is the standard schedule and why steady-state is approached over roughly four to five weeks — the same interval used to hold each titration step.

Is retatrutide approved for human use?

No. Retatrutide is an investigational compound with no regulatory approval for human use. Titan Peptide Lab supplies it strictly as a research-use-only reagent for in-vitro laboratory work — not for human or animal consumption, and not for diagnostic, therapeutic, or preventative use. Nothing on this page is medical or dosing advice.

Retatrutide · 10mg vial · research use only

Retatrutide dosage, read straight from the trial data.

Retatrutide (LY3437943) is a triple agonist at the GLP-1, GIP and glucagon receptors, and the dosing schedule that defines it comes from a published Phase 2 obesity trial rather than guesswork. This page lays out the weekly amounts the literature actually used, the four-week titration steps, the reconstitution math for a 10mg lyophilized vial, and the ~6-day half-life that explains the once-weekly cadence — framed as a research reference, not a human dosing protocol or medical advice.

Retatrutide 10mg vial — $199.99 Reconstitution calculator

The titration the trial used

The Phase 2 obesity study (NEJM, Jastreboff et al., 2023) escalated subcutaneous retatrutide in stepwise fashion: cohorts targeted 1, 4, 8 and 12 mg once weekly, with the higher arms starting at 2 mg and stepping up every four weeks. The slow ramp — typically 2 mg → 4 mg → 8 mg → 12 mg, four weeks per step — was used to manage the GI tolerability that defines the GLP-1/GIP/glucagon class. Researchers model the same staged escalation rather than starting at the top dose.

View the 10mg vial →

Reconstitution math, 10mg vial

Titan's retatrutide ships as a single 10mg lyophilized vial. Reconstitute with bacteriostatic water and the concentration is fixed by the volume you add: 2 mL of BAC water yields 5 mg/mL, so a 0.04 mL draw on a U-100 insulin syringe is 2 mg, 0.08 mL is 4 mg, and 0.16 mL is 8 mg. Add 1 mL instead and every mark doubles in strength. Confirm the math against the calculator before any in-vitro work — the vial is 10 mg total, enough to model the full titration ladder.

Run the numbers →

Half-life sets the cadence

Retatrutide's terminal half-life is reported at roughly 6 days (~144 hours), which is what makes once-weekly the standard schedule in the trials — one administration keeps plasma concentration in a working band across the interval. Practically, it also means steady-state is approached over about five half-lives (~4–5 weeks), which is why each titration step is held for four weeks before escalating.

Reconstituted shelf life →

Format and purity to confirm

Before modelling any dose, confirm what you're working with. Titan's retatrutide is a 10mg lyophilized powder with an HPLC main-peak result against a ≥99% internal purity target and mass-spec identity confirmation, documented on a lot-matched release sheet. Identity and purity are the variables that actually move a dosing model — a mislabelled or impure lot makes the cleanest titration math meaningless.

See the testing workflow →

Where retatrutide sits vs. the class

Retatrutide is dosed in single-digit milligrams weekly — the same order of magnitude as tirzepatide and an order above semaglutide — because it is a small, potent multi-receptor agonist. If a protocol is comparing GLP-1-class agents, the dosing differences matter: semaglutide tops out around 2.4 mg weekly while retatrutide trial arms ran to 12 mg. The comparison pages break down how the receptor targets and dose ranges differ.

Retatrutide vs the GLP-1 class →

Research-use framing

These figures describe the doses reported in human clinical trials and are reproduced here as a research reference for in-vitro and laboratory modelling — not as instructions for human use. Retatrutide is an investigational compound with no regulatory approval. Titan supplies it strictly as a research reagent, not for human or animal consumption, and nothing here is medical or dosing advice.

Research-use policy →

The detail, in plain terms

The dosing reference, in one table.

Retatrutide's dosing is unusually well-defined for a research compound because the Phase 2 trial published its escalation schedule. These are the variables a researcher actually weighs when modelling a titration — reproduced as a reference, not a human protocol.

Compound: Retatrutide (LY3437943) — triple GLP-1 / GIP / glucagon receptor agonist.
Trial dose arms: 1, 4, 8 and 12 mg once weekly (Phase 2 obesity trial, subcutaneous).
Titration: Typical ramp 2 → 4 → 8 → 12 mg, four weeks held per step.
Half-life: ≈6 days (~144 h) terminal — basis for the once-weekly cadence.
Format: 10mg lyophilized vial, $199.99 — reconstitute before in-vitro use.
Reconstitution: 2 mL BAC water → 5 mg/mL (0.04 mL = 2 mg); 1 mL → 10 mg/mL.

Questions researchers ask

Before you order.

What doses of retatrutide were used in the research?: The Phase 2 obesity trial (Jastreboff et al., NEJM 2023) tested subcutaneous retatrutide in cohorts targeting 1, 4, 8 and 12 mg once weekly. The higher-dose arms began at 2 mg and escalated in stepwise fashion. These figures are reproduced as a laboratory research reference; they are not a human dosing protocol or medical advice.
How is retatrutide titrated in the literature?: The trials used a slow stepwise escalation — commonly 2 mg, then 4 mg, then 8 mg, then up to 12 mg — holding each step for about four weeks before moving up. The gradual ramp manages the gastrointestinal tolerability characteristic of GLP-1/GIP/glucagon agonists. Four weeks per step also roughly matches the time to approach steady-state given the ~6-day half-life.
How do I reconstitute a 10mg retatrutide vial?: Add bacteriostatic water to the lyophilized powder; the concentration depends on the volume. Adding 2 mL gives 5 mg/mL, so 0.04 mL on a U-100 insulin syringe equals 2 mg, 0.08 mL equals 4 mg, and 0.16 mL equals 8 mg. Adding 1 mL gives 10 mg/mL and halves those draw volumes. Always verify against the reconstitution calculator before any in-vitro work.
What is retatrutide's half-life?: Retatrutide's terminal half-life is reported at roughly 6 days (about 144 hours). That long half-life is why once-weekly administration is the standard schedule and why steady-state is approached over roughly four to five weeks — the same interval used to hold each titration step.
Is retatrutide approved for human use?: No. Retatrutide is an investigational compound with no regulatory approval for human use. Titan Peptide Lab supplies it strictly as a research-use-only reagent for in-vitro laboratory work — not for human or animal consumption, and not for diagnostic, therapeutic, or preventative use. Nothing on this page is medical or dosing advice.