Retatrutide (GLP3-RT) — Complete Dosing Protocol & Guide

Retatrutide (GLP3-RT) is taken subcutaneous — subcutaneous injection into abdominal fat is the standard research route. The research-standard frequency is once weekly, with a half-life of ~144 hours (~6 days). Keep administrations on the same day(s) each week so plasma levels stay steady. Always start at the low end of the dose range, use aseptic technique for injections, and follow the 16-24 weeks cycle followed by 4-8 weeks off. PeptideWise calculates the exact dose and schedule for your body weight and goal.

Research protocols use 1 mg–12 mg per administration, weight-based at roughly 60 mcg/kg of body weight. For an 80 kg (176 lb) adult that works out to about 1.6 mg for a beginner, 2.4 mg for an intermediate, and 3.6 mg for an advanced research protocol. Start at the bottom of the range and titrate up only while the response is tolerable — the personalized protocol engine on this site computes the exact figure for your weight.

The standard research cycle is 16-24 weeks, followed by 4-8 weeks off. Cycling matters because continuous exposure leads to receptor desensitization (tachyphylaxis) — the same dose produces less effect over time — and side effects fade during off periods. Don't extend the cycle past 16-24 weeks chasing diminishing returns.

Retatrutide (GLP3-RT) is a potent incretin-pathway agent, and research protocols deliberately keep it as a standalone: combining multiple GLP-1/glucagon/GIP agonists multiplies GI side effects (nausea, vomiting, delayed gastric emptying) without evidence of additive benefit.

Reported in research and trial settings: nausea; vomiting; diarrhea; constipation; decreased appetite; injection site reactions. Most are dose-dependent and resolve when the dose is reduced or the cycle ends. If any severe reaction occurs (chest pain, severe abdominal pain, difficulty breathing, signs of an allergic response), stop immediately and seek medical evaluation.

Retatrutide (GLP3-RT) carries a good research safety profile at the doses described above, but safety is individual. It is contraindicated in research settings with: medullary thyroid carcinoma, mens2, pancreatitis, gastroparesis, pregnant, breastfeeding, insulin. It is not medical advice to run any peptide without supervision — consult a qualified healthcare provider who knows your full history first, get baseline labs, and re-check during the cycle. 🔥 As a weight loss peptide, Retatrutide (GLP3-RT) is sold for research use only.

Retatrutide (GLP3-RT) is sold by research-chemical suppliers for laboratory research use only — it is not an approved dietary supplement or consumer product, and regulations vary by country and jurisdiction. Before considering any source: (1) consult a licensed healthcare provider about medically supervised options, (2) if purchasing for research, verify third-party certificates of analysis (COA) confirming purity and identity, and (3) be wary of prices that look too good to be true — they usually are. PeptideWise does not sell peptides; we provide dosing research and protocol tools.

Retatrutide (GLP3-RT) ships lyophilized (freeze-dried) and must be reconstituted before use. Use bacteriostatic water: inject it slowly down the inside wall of the vial (never directly onto the powder), then swirl gently — never shake, as shaking denatures the peptide. Example: a 5 mg vial + 2 mL of bacteriostatic water gives 2.5 mg/mL, so a 250 mcg dose is 10 units (0.1 mL) on an insulin syringe. Store the reconstituted vial refrigerated at 2–8°C and use within 2–4 weeks. See the full step-by-step reconstitution guide for concentration math and storage.