Retatrutide Dosage Chart
Retatrutide is a once-weekly triple agonist targeting GLP-1, GIP, and glucagon receptors. The Jastreboff Phase 2 trial (NEJM 2023) reported up to 24.2% mean body-weight reduction at 48 weeks with the 12mg dose, and Lilly's TRIUMPH-4 Phase 3 readout (Dec 11, 2025) confirmed 12mg as the lead dose.
Half-life
~6 days
Format
Injectable
Purity
≥99%
Protocols
5 variants
Research Protocols
Dosage Protocols
Each row reflects a common research protocol variant. These are reference ranges derived from published literature and community research — not medical guidance.
Protocol 1
Titration Phase 1 (Weeks 1-4)
Dose
2mg subcutaneous once weekly
Duration
4 weeks
Starting dose used in the Jastreboff 2023 Phase 2 trial (PMID 37366315). Tri-agonist activity makes early GI adaptation noticeable; do not skip this step.
Protocol 2
Titration Phase 2 (Weeks 5-8)
Dose
4mg once weekly
Duration
4 weeks
Second titration step from the published Phase 2 protocol. Hold here for an extra 2-4 weeks if appetite suppression or nausea is meaningful.
Protocol 3
Titration Phase 3 (Weeks 9-12)
Dose
8mg once weekly
Duration
4 weeks
Third titration step. Phase 2 reported the 8mg group at 22.8% mean body-weight reduction by week 48 (Jastreboff 2023).
Protocol 4
Standard Maintenance Protocol
Dose
12mg once weekly
Duration
Ongoing (re-evaluated quarterly)
Lead dose in TRIUMPH-4 Phase 3 (Lilly press release, Dec 11, 2025). The 12mg arm in Phase 2 produced 24.2% mean body-weight loss at 48 weeks. Reach only after stepwise titration.
Protocol 5
Conservative Research Variant
Dose
4-8mg once weekly
Duration
16-24 weeks
Lower-ceiling protocol used by researchers prioritizing tolerability over peak effect. Phase 2 showed strong response curves at both doses.
Mixing Math
Reconstitution
Reference values for preparing a research vial. Adjust the syringe reading if you change the water volume.
Vial size
10mg vial
BAC water
2ml bacteriostatic water
Concentration
5mg/ml
Dose / ml
2mg = 0.4ml · 4mg = 0.8ml · 8mg = 1.6ml
Syringe units
40 IU (2mg) · 80 IU (4mg) · 160 IU (8mg) on U-100
Frequently Paired
Common Stacks
Storage
Handling Notes
Lyophilized: -20°C long-term, 2-8°C for short-term. Reconstituted: refrigerate at 2-8°C and use within 28 days. Do not shake; swirl gently to mix.
Research Considerations
Cautions
- Retatrutide is investigational. As of April 2026 it is not FDA approved for any indication. No approval timeline is implied.
- Triple-agonist activity (GLP-1 + GIP + glucagon) can elevate heart rate and shift glucose metabolism. Baseline labs and ongoing monitoring are essential.
- Pairing with cagrilintide is preliminary and not validated in published Phase 3 data. Most published research uses retatrutide as a standalone.
- Slow titration is non-negotiable. Skipping steps amplifies GI adaptation and tachycardia risk.
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Buy Retatrutide nowResearch use only. Not medical advice. Browse all dosage charts