Retatrutide
A once-weekly triple agonist (GIP, GLP-1 and glucagon) with the largest weight loss seen so far in trials.
Investigational (phase 3); not approved.
Used for
- Weight loss
- Liver fat
- Type 2 diabetes
How it works
Glucagon action adds energy burn and liver fat loss on top of GIP/GLP-1 appetite effects.
Half-life: about 6 days
What the research shows
- Phase 2 (48 weeks): 24.2% average weight loss on 12 mg vs 2.1% on placebo.
- Side effects were mostly stomach-related and dose-dependent; starting at 2 mg instead of 4 mg reduced them. Heart rate rose, peaking around week 24.
- Phase 3 TRIUMPH-2 (80 weeks, obesity with type 2 diabetes): 11.9%, 16.8% and 18.8% weight loss on 4, 9 and 12 mg vs 5.1% on placebo. Dysesthesia (tingling or painful skin) hit 4–7% vs 1%, and low blood pressure up to 6%; 8–12% on 9–12 mg stopped for side effects.
Dosing
Dosing isn’t listed on the public site. In the app, each published option is shown with its source (a drug label, a clinical guideline, a trial or community reports) and can be turned into a protocol you review.
Work out the units to draw for your vial →Side effects
- Nausea, especially after a dose step
- Constipation or diarrhea
- Reflux, burping
- Lower appetite and thirst: dehydration risk
- Faster resting heart rate
- Skin tingling, burning or sensitivity (dysesthesia): 4–7% in phase 3, more at higher doses
- Low blood pressure or dizziness on standing, mostly at 9–12 mg
Cautions
- Not for anyone with a personal or family history of medullary thyroid cancer or MEN2.
- Pancreatitis and gallbladder problems are uncommon but reported; severe belly pain needs urgent care.
- Rapid weight loss costs muscle too: keep protein high and keep lifting.
- Stop before planned surgery or sedation per your doctor (slower stomach emptying).
- Not approved: long-term safety is still being studied.
- Research-chemical vials have no quality control: purity, dose and sterility vary. Third-party testing helps but is no guarantee.
Storage
Unmixed powder: freezer or fridge, away from light.
Once mixed with bacteriostatic water: fridge; the common rule is to use it within 28 days.
There is no label or published stability data for this one, so treat these as habits, not limits.
Stability once mixed
Designed for once-weekly use (half-life about 6 days), built like tirzepatide with a fatty-acid side chain. No label or pen data for a vial you mix.
Heat, shaking, freezing a mixed vial, light and many needle punctures all speed breakdown. Toss it if it turns cloudy, grows specks or changes color.
More in Weight & metabolic
Reference only, not medical advice. Written for this app from the cited research. Doses marked community-reported are not from trials.