Peptide Schedule

Retatrutide

Weight LossInjectionPhase 2Grade C~6 days half-life
GLP-1 AgonistGIP AgonistGlucagon AgonistTriple AgonistWeight Management

Benefits

Triple-action: GLP-1 + GIP + glucagon receptors
Up to 24% body weight loss in clinical trials
Reduces liver fat significantly
Improves metabolic markers (insulin, lipids)
Weekly dosing
Half-Life
~6 days
Route
Injection
Frequency
Weekly
Vial Sizes
5mg, 10mg, 15mg
BAC Water
2mL
Safety Grade
Grade C
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About Retatrutide

Retatrutide is the first triple-agonist peptide, targeting GLP-1, GIP, and glucagon receptors simultaneously — earning it the nickname 'Triple G.' In phase 2 trials, participants lost up to 24% of body weight at the highest dose, making it potentially the most powerful weight loss peptide ever studied. The glucagon component adds direct fat-burning and liver fat reduction beyond what GLP-1 alone achieves.

Who Should Consider Retatrutide

  • Adults with BMI ≥30 (or ≥27 with weight-related comorbidity)
  • Individuals seeking maximum weight loss beyond dual-agonist options
  • Adults with metabolic dysfunction-associated steatotic liver disease (MASLD)
  • Patients with obesity-related comorbidities (type 2 diabetes, dyslipidemia)
  • Adults who have plateaued on GLP-1 or dual-agonist therapy

How Retatrutide Works

Retatrutide activates three receptors simultaneously: GLP-1 (suppresses appetite, slows gastric emptying), GIP (enhances insulin secretion, improves fat metabolism), and glucagon (increases energy expenditure, promotes liver fat oxidation). This triple mechanism produces greater weight loss than single or dual agonists by attacking fat storage and energy balance from multiple pathways.

What to Expect

Weeks 1-4
1mg

Titration initiation. Mild appetite reduction begins. GI side effects (nausea, decreased appetite) are most common early. Body adjusts to triple-receptor activation.

Weeks 5-8
2-4mg

Appetite suppression becomes more pronounced. Early weight loss of 3-5%. GI side effects typically begin to ease as the body adapts to escalating doses.

Weeks 9-16
4-8mg

Steady weight loss accelerates. Liver fat reduction becomes measurable. Blood sugar and lipid markers improve. Most users experience 8-12% body weight reduction.

Weeks 17-24
8-12mg

Approaching full therapeutic dose. Clinical trials showed ~17.5% mean weight loss at 24 weeks. Significant metabolic improvements across multiple markers.

Weeks 24-48
12mg maintenance

Full dose maintenance. Phase 2 trials showed up to 24.2% body weight loss at 48 weeks. Liver fat reduced by over 80% at higher doses. Weight loss rate slows as a new equilibrium is reached.

Dosing Protocol

LevelDose / InjectionFrequency
Beginner1mgWeekly
Moderate4mgWeekly
Aggressive8mgWeekly

Note: Triple-agonist: GLP-1 + GIP + glucagon. Up to 24% body weight loss in trials. Titrate from 1mg weekly over 12+ weeks. Also improves liver fat and metabolic markers.

How to Inject Retatrutide

Inject subcutaneously once weekly. Rotate injection sites between abdomen, thigh, and upper arm. Follow the titration schedule strictly — start at 1mg and escalate slowly over 12+ weeks to minimize GI side effects.

Pharmacokinetics

Half-Life
144h
Bioavailability
SC: not yet formally reported
Tmax
12-72 hours
Data Confidence
moderate

Source: NEJM Phase 2 Trial (NCT04881706), ~6 days

Pharmacokinetics — Active Dose Over Time

t½ = ~6 days
50%25%12.5%100%75%50%25%0%06d12d18d24d30dTime after injectionDose remaining
After 1 half-life (6d): 50% remainsAfter 2 half-lives (12d): 25% remainsAfter 3 half-lives (18d): 12.5% remains
At a 4mg dose: 50% = 2.0mg remaining after 6d. Recommended frequency: Weekly.

Disclaimer: This curve is a simplified first-order exponential decay model. Actual pharmacokinetics vary based on injection site, individual metabolism, body composition, and other factors. Half-life values are approximate and based on available preclinical and clinical literature. Many research peptides lack formal human pharmacokinetic studies. This is for educational purposes only — not medical advice.

Side Effects

Nausea, diarrhea, vomiting (especially during dose escalation). Decreased appetite. Constipation. Slow titration critical.

Contraindications

  • Personal or family history of medullary thyroid carcinoma (MTC)
  • Multiple Endocrine Neoplasia syndrome type 2 (MEN2)
  • History of pancreatitis
  • Pregnancy or breastfeeding
  • Known hypersensitivity to retatrutide or any excipients
  • Severe gastrointestinal disease (e.g., gastroparesis)

Drug Interactions

  • Insulin and sulfonylureas — increased hypoglycemia risk due to combined glucose-lowering effects
  • Oral medications may have delayed absorption due to slowed gastric emptying
  • Levothyroxine — monitor thyroid levels as absorption timing may be altered
  • Warfarin — monitor INR more frequently during initiation and dose changes

Storage & Stability

Before Reconstitution
Refrigerate at 2-8°C
After Reconstitution
Refrigerate, use within 4 weeks
Temperature
2-8°C (36-46°F)

Molecular Profile

Amino Acids
35
Molecular Weight
4,731.33 Da
Sequence
YQGTFTSDYSILDKKAQAFIEYLLEGGPSSGAPPPS
HydrophobicPolarPositiveNegativeSpecial

Related Peptides

Semaglutide
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Tirzepatide
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Mazdutide
Weight Loss

References

  1. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial (NEJM 2023)PubMed 37366315
  2. Retatrutide for People with Type 2 Diabetes — A Phase 2 Trial (Lancet 2023)PubMed 37385280
  3. Retatrutide for Metabolic Dysfunction-Associated Steatotic Liver Disease — Phase 2a Trial (Nature Medicine 2024)PubMed 38858523
  4. Retatrutide Delays Gastric Emptying — GIP, GLP-1 and Glucagon Receptor Agonist (Diabetes Obes Metab 2023)PubMed

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