Overview
Retatrutide is a revolutionary triple-hormone receptor agonist (tri-agonist) targeting GLP-1, GIP, and Glucagon receptors simultaneously.
What problem it targets: It targets severe obesity, morbid weight-loss plateaus, Type 2 diabetes, non-alcoholic fatty liver disease (MASLD), and sluggish resting metabolic rates.
What It Does
• Unprecedented triple-action synergy: GLP-1 curbs appetite, GIP enhances insulin secretion and fat storage flexibility, and Glucagon dramatically elevates resting caloric expenditure.
• Accelerates hepatic fat burning: Direct glucagon receptor activation stimulates the liver to burn stored liver fat rapidly, reversing metabolic fatty liver disease.
• Delivers historic weight-loss percentages: Phase 2 human trials demonstrated up to ~24% average total body weight loss at 48 weeks, outperforming all single and dual agonists.
• Realistic expectations: Administered as a once-weekly subcutaneous injection. Titrated slowly over months to allow gastrointestinal and heart-rate adaptation; profound appetite reduction begins immediately.
RECONSTITUTION, 20 MG/ML, 1 UNIT = 0.2 MG
| Vial size | BAC water | Concentration | Note |
|---|---|---|---|
| 5 mg | + 0.25 mL | 20 mg/mL | 1 unit = 0.20 mg (mg × 5 = units) |
| 10 mg | + 0.50 mL | 20 mg/mL | |
| 15 mg | + 0.75 mL | 20 mg/mL | |
| 20 mg | + 1 mL | 20 mg/mL | |
| 30 mg | + 1.5 mL | 20 mg/mL | |
| 60 mg | + 3 mL | 20 mg/mL |
TITRATION, ONCE WEEKLY, SELF-PACED (SYMPTOM-GATED)
| Weekly dose | Units @ 20 mg/mL | Hold before stepping up |
|---|---|---|
| 0.5 mg | 2.5u | ~1 week |
| 1 mg | 5u | ~1 week |
| 2 mg | 10u | 2–4 weeks |
| 3 mg | 15u | 2–4 weeks |
| 4 mg, sweet-spot range begins | 20u | As needed, 2–4 weeks+ |
| 5 mg | 25u | As needed, 2–4 weeks+ |
| 6 mg | 30u | As needed, 2–4 weeks+ |
| 7 mg | 35u | As needed, 2–4 weeks+ |
| 8 mg | 40u | As needed, 2–4 weeks+ |
| 9 mg | 45u | As needed, 2–4 weeks+ |
| 10 mg | 50u | As needed, 2–4 weeks+ |
| 11 mg | 55u | As needed, 2–4 weeks+ |
| 12 mg, ceiling | 60u | Max dose, do not exceed Pace it yourself, nothing here is on a clock. Move through 0.5 → 1 → 2 mg (~1 week each), then step +1–2 mg as you feel ready, only when nausea-free. Hold each dose as long as it’s still working, you never have to go up. Most find their sweet spot at 4–8 mg; 12 mg is the ceiling; above ~6 mg is prescriber territory. Sex note: women tend to lose more and tolerate less, start at the low end. Split it to ease nausea. Any weekly dose can go as two smaller shots/week (e.g. Mon & Thu), same weekly total, lower peak. Halve the mg and units (4 mg / 20u once → 2 mg / 10u twice). 1 unit = 0.2 mg, so mg × 5 = units. Women: Women lose more than men at the same dose but report more GI (start lower). In PCOS they improve cycles, lower free testosterone and raise ovulation; a real unplanned-pregnancy risk. Stop before conceiving. Men: In men, excess fat lowers testosterone; GLP-1 raises total testosterone, SHBG and gonadotropins as weight drops, and improves sperm and erectile function; and preserves fertility, unlike TRT (which suppresses sperm). |
Handling & Supply
- Freeze-dried: -4°F.
- Reconstituted: 36–46°F.
- Best used within 28 days, otherwise potency gradually fades over ~4–6 weeks (structure-based estimate, no published data); once punctured, sterility is the real limit.
- Supply a vial lasts its mg ÷ the weekly dose, at the 4–8 mg/week sweet spot a 15 mg vial runs ~2–4 weeks (10 mg → ~1.25–2.5 wks), so roughly 14–28 vials/year.
- Vials run continuously across dose changes, no waste.
- Semaglutide or Tirzepatide simultaneously, or any other GLP-1 receptor agonist (additive GI, GLP-1 desensitisation).
- Insulin without monitoring.
- RETATRUTIDE, FDA vs COMMUNITY & SAFETY
CURRENT FDA TRIAL SCHEDULE (TRIUMPH, ONCE WEEKLY, FIXED CALENDAR)
| Weeks | Dose (once weekly) | Notes |
|---|---|---|
| 1–4 | 2 mg | Fixed starting dose for everyone. |
| 5–8 | 4 mg | The 4 mg target group stops climbing here. |
| 9–12 | 6 mg | |
| 13–16 | 9 mg | The 9 mg target group stops here. |
| 17+ | 12 mg | The 12 mg group, the trial ceiling. How to read it: everyone starts at 2 mg once weekly and steps up on a fixed 4-week calendar (2 → 4 → 6 → 9 → 12 mg). Each person was assigned a target of 4, 9, or 12 mg and simply stopped climbing once they reached it. No dose-splitting; pace is set by the calendar, not by symptoms. |
COMMUNITY CONSENSUS, WHAT REAL-WORLD USERS DO DIFFERENTLY
Frequency Same weekly dose, but often split 2×/week (Mon/Thu) to lower each peak and shrink the shot; the main nausea lever.
Start & pace Start lower (0.5–1 mg, ~1 week each), then a gentle +1 mg every 2–4 weeks (some experienced users step +2 mg every 4–6 wks). Symptom-gated, step up only when nausea-free, never on a fixed date.
Target Aim for the minimum effective dose, most plateau at a 4–8 mg sweet spot rather than pushing to 12.
Bottom Line
Same result, less nausea.
Weight loss tracks your total weekly dose, so splitting the dose or raising it more slowly doesn’t cost results; the Phase 2 trial found a slower ramp caused fewer stomach side effects with the same weight loss.
The community version is just a gentler road to the same place.
Above ~6 mg the tougher side effects climb (odd skin sensations, higher heart rate, blood-sugar changes); prescriber territory.
Trial results TRIUMPH-1 (obesity, 80 wks): 28.3% at 12 mg (45.3% lost ≥30%, surgical-level), 30.3% at 104 wks. TRIUMPH-4 (obesity + knee OA, 68 wks): 28.7% at 12 mg, 26.4% at 9 mg. TRANSCEND-T2D-1 (diabetes, Lancet Jun 2026): A1c −2.0%, 16.8% weight loss at 12 mg.
Sources Phase 3 TRIUMPH (the main FDA-approval trial); Phase 2 obesity & T2D (NCT04867785); titration-scheme trial NCT07357415. Investigational, not FDA-approved.
Safety & Patient Education
- Triple-agonist: GI tolerance significantly worse than dual or single agonists at high doses Abnormal skin sensations, dose-dependent abnormal skin sensation; new in Phase 3 (~12.5% at 12 mg vs 0.9% placebo), not seen in Phase 2 Glucagon component raises glucose excursions; heart-rate elevation (~5–10 bpm) can be more pronounced Acute pancreatitis: discontinue if suspected (severe abdominal pain radiating to back) Acute gallbladder disease; diabetic retinopathy progression; acute kidney injury from GI-related volume depletion (highest during escalation) Severe GI: ileus, obstruction, severe constipation, fecal impaction.
- Anaphylaxis/angioedema reported.
- Aspiration risk under anesthesia.
- Delayed gastric emptying affects oral absorption (levothyroxine, oral contraceptives, warfarin); separate timing.
- Insulin / secretagogues: reduce at initiation.
- Do not combine with other GLP-1 agonists.
- Baseline: BMP/CMP, CBC, HbA1c, lipid panel, TSH, pregnancy test.
- BMP at every dose escalation and any time GI side effects cause >24h reduced intake.
- HbA1c at 3 + 6 mo; lipids at 6 mo; repeat eGFR if dehydration signs.
- Lipase if abdominal pain.
- Drop hsCRP / routine calcitonin., Out of range?
- Rising glucose/HbA1c = blood sugar creeping toward diabetes (recheck, tighten diet); a falling eGFR = kidney strain, usually dehydration (hydrate, hold the dose).
- Creatinine rise >0.3 mg/dL or eGFR drop >20%: hold, rehydrate.
- Severe abdominal pain: evaluate for pancreatitis.
- Vision changes: ophthalmology.
- Persistent vomiting >48h: hold.
- New neck mass / hoarseness / dysphagia: thyroid workup.
- acute kidney injury on GLP-1s is from dehydration, not the drug.
- Target 2.5–3 L water/day; hold next dose for any day of vomiting/diarrhea/reduced food; resume same level after 24h recovery.
- Required during any GLP-1 cycle: protein 1.2 g/kg IBW/day (1.6 if training), resistance training 2–3×/wk, creatine 5 g/day; without this, 25–40% of weight lost is lean mass and regain is rapid.
- Eat slowly, stop at first fullness.
- Inform any anesthesiologist before procedures.
- Pen/vial sharing prohibited.
- Sulfur (“rotten-egg”) burps mean the stomach is emptying too slowly, a sign the dose is too high.
- Hold or step back down rather than going up, and let it settle before increasing again.
- Not FDA-approved.
- Phase 3 reading out; no NDA filed yet (filing expected Q4 2026–Q1 2027), no brand name.
- Compounded versions are not equivalent to clinical-trial product.
