Retatrutide

• Lowest escalated trial armrecommended

  Reproduces the phase 2 4 mg arm that started at 2 mg. Shown first only because it has the lowest exposure; no regimen is clinically recommended.

• Mid-dose trial arm

  Reproduces the phase 2 8 mg arm that started at 2 mg (2, 4, then 8 mg).

• Highest trial arm

  Reproduces the phase 2 12 mg arm (2, 4, 8, then 12 mg). Highest dose studied in this trial.

• Trial arms (once weekly, subcutaneous): 1 mg fixed; 4 mg (2 mg start, then 4 mg); 8 mg (2 mg start: 2, 4, 8 mg); 12 mg (2 mg start: 2, 4, 8, 12 mg).
• Escalation in the trial: every 4 weeks for up to 12 weeks (NEJM abstract/methods as summarised in search results; the registry lists the steps but not the interval).
• Trial duration 48 weeks.

Route: Subcutaneous, once weekly (as in the trial).

Timing: Same weekday each week. No reliable figure found in the sources; ask your prescriber or supplier.

• No label exists, so no sourced reconstitution. The 20 mg vial size and the water volumes in the protocols are placeholders chosen so the reference dose draws about 40 units (not sourced): confirm the vial strength on your supplier's label.

No reliable figure found in the sources; ask your prescriber or supplier.

None: the trial dosed continuously for 48 weeks.

Why:

• Trial design, not a recommendation to continue beyond 48 weeks.

• Never draw into the same syringe as another compound; use separate syringes and distinct injection sites.

Investigational; not approved by FDA or EMA. Products sold online as 'research' retatrutide are not GMP-verified.

Common side effects:

• Gastrointestinal events were the most common adverse events in the phase 2 trial; they rose with dose and were reduced by the 2 mg starting dose.

What sources report this compound changes, or say to check. A record of the evidence, not targets or advice.

• Body weightReported changeHuman trial

  Mean change at 48 weeks: -8.7% (1 mg) to -24.2% (12 mg) vs -2.1% placebo (phase 2, obesity)

  PubMed record of the phase 2 trial (Jastreboff, NEJM 2023)
• Heart rateReported changeHuman trial

  Dose-dependent increases peaked at 24 weeks and declined thereafter

  PubMed record of the phase 2 trial (Jastreboff, NEJM 2023)

• NEJM phase 2 obesity trial (Jastreboff 2023)
• ClinicalTrials.gov NCT04881760: arms and dose escalation
• PubMed record of the phase 2 trial