Rétatrutide
Triple agoniste GLP-1 / GIP / Glucagon
Retatrutide is a triple agonist of the GLP-1, GIP, and glucagon receptors, involved in the regulation of energy homeostasis. It acts on appetite, energy management, and certain metabolic mechanisms.
Titration Protocol
Dose escalation method, for informational purposes.
Chemical identity
- Sequence
- 39-mer modifié (résidus Aib, α-Me-Leu, Lys acylée C20 ; amide C-terminal)
- Molecular formula
- C221H342N46O68
- Molecular weight
- 4731.33 g/mol
- CAS no.
- 2381089-83-2
Purity (HPLC) measures the absence of related impurities; it is distinct from net peptide content, since salts and counter-ions (acetate, TFA) count toward the vial mass. Account for this when computing the real concentration at reconstitution.
Potential benefits
Reduced appetite
Naturally reduces hunger by acting on central satiety signals.
Stabilized blood sugar
Improves glucose-dependent insulin response.
Energy expenditure
May increase energy expenditure via the glucagon pathway.
Fat oxidation
Promotes lipolysis and the use of lipids as fuel.
Mechanism of action
- GLP-1: activation of POMC/CART neurons (satiety), inhibition of NPY/AgRP (hunger), slowing of gastric emptying.
- GIP: improvement of glucose-dependent insulin response, modulation of lipid metabolism.
- Glucagon: activation of lipolysis, increased energy expenditure, lipid oxidation.
- Long half-life (~5 to 6 days) → gradual accumulation; steady state reached after ~4 to 5 weeks.
- The synergy of these three pathways explains the superior efficacy compared with single agonists.
Historical milestones
Research milestones, clinical trials and regulatory steps.
- 2022
First-in-human study
Phase 1 results of LY3437943 in healthy and type 2 diabetic volunteers are published, supporting once-weekly dosing.
- Jun 2023
Phase 2 results
A phase 2 trial in the NEJM shows up to 24.2% body-weight loss at 48 weeks on the 12 mg dose.
- 2023
TRIUMPH program launch
Eli Lilly starts the phase 3 TRIUMPH program spanning several trials in over 5,800 participants.
- Dec 2025
First phase 3 readout
The TRIUMPH-4 trial reports a mean body-weight reduction of 28.7% at 68 weeks on the 12 mg dose.
- 2026
Further TRIUMPH readouts expected
Data from TRIUMPH-2 (type 2 diabetes) and TRIUMPH-3 (cardiovascular disease) are expected during the year.
Evolution over time
Initial adaptation: reduced appetite, possible early digestive effects.
Stabilization: more stable satiety, more stable energy, onset of fat mass loss.
Optimal progression: steadier weight loss, better fat utilization.
Dosages & protocol
Reference dosages
16 wk
Evening (better tolerance)
~5 to 6 days — compatible with a single weekly injection (steady state after ~4-5 weeks)
Titration protocol
Stay on one step and let natural accumulation work. Progress slowly.
Accumulation logic
Retatrutide has a long half-life (~5 to 6 days). Even without increasing doses, the overall effect naturally increases over time. It is essential to progress slowly, let the body adapt, and avoid rapid increases.
Signs to monitor
- Positive: natural satiety, stable energy, proper digestion, gradual weight loss.
- To adjust: significant fatigue, dizziness / headaches, muscle cramps, total loss of appetite.
Golden rule
Daily consistency beats occasional intensity. Adjustments are often needed, but they should be made intelligently, based on data (weight, waist circumference, hunger, energy) rather than emotions.
Suggested adjustment scale (indicative)
- Insufficient loss / plateau → increase by 0.25 to 0.5 mg every 2 to 4 weeks.
- Too-rapid loss (> 1%/week) → decrease by 0.25 to 0.5 mg or increase calories.
- Bothersome side effects → decrease the dose or pause for 1-2 weeks.
Usage tips
- A slow progression is described: no increase beyond the protocol without reason.
- Research protocols describe evening administration for better tolerance.
- Optimal hydration and electrolyte intake (sodium, potassium, magnesium).
- Split meals: 4 to 6 small meals per day.
- Prioritize sufficient protein intake (1.6 to 2.2 g/kg) to preserve lean mass.
- Keep a journal: symptoms, meals, hydration, sleep.
Good to know / effects to watch
- Nausea (the most common effect, especially at the start of the protocol or after a dose increase).
- Bloating & gas, early satiety, transit disturbances.
- Headaches & fatigue, transient mood changes.
- Most effects subside in 80 to 90% of cases within a few days to weeks.
- Warrants monitoring (consult if severe/persistent): repeated vomiting, severe abdominal pain, severe hypoglycemia.
Storage
- Before reconstitution (lyophilized powder): refrigerated (2-8 °C), away from light; tolerates short periods at room temperature during shipping.
- After reconstitution: refrigerated (2-8 °C), typically use within ~4 weeks (28 days).
- Do not freeze the reconstituted solution, do not shake vigorously, avoid heat and direct light.
Contraindications
- Pregnancy and breastfeeding: avoid.
- Personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN 2): class contraindication (incretin agonists).
- History of pancreatitis; severe gastrointestinal disease or gastroparesis: caution.
- Interactions: increased hypoglycemia risk when combined with insulin or sulfonylureas; delayed gastric emptying may alter absorption of other oral drugs.
- Unapproved research compound: human use not validated.
Possible synergistic combinations
Sodium, potassium, magnesium — help prevent fatigue, cramps, and headaches.
Help preserve lean mass during a caloric deficit.
Sources & references
Links to external sources (scientific databases, trial registries, authorities). RAL Peptides is not responsible for their content.
⚠ For research use only. NOT intended for use on humans or animals. The values shown are indicative and for informational purposes ; each person reacts differently. This guide does not replace medical advice — consult a healthcare professional if in doubt.