Retatrutide
An experimental triple-action drug targeting GLP-1, GIP, and glucagon receptors. Early trials show up to 24% body weight loss — more than any existing medication.
Retatrutide is a next-generation weight-loss drug being developed by Eli Lilly. It's a "triple agonist" — it activates GLP-1, GIP, and glucagon receptors simultaneously. Phase 2 data showed up to 24% weight loss, exceeding both semaglutide and tirzepatide.
Good for you if: You're interested in the future of obesity medicine. Retatrutide is not yet available for prescription — it's in Phase 3 clinical trials. This page covers what we know so far.
Dive deeper into the researchCommon side effects
- GI side effects similar to other GLP-1 drugs — nausea, diarrhoea
- Glucagon component may increase heart rate slightly
- Long-term safety data not yet available (experimental)
What does retatrutide do?
Retatrutide adds a third target — the glucagon receptor — on top of the GIP and GLP-1 receptors that tirzepatide hits. Glucagon increases energy expenditure and promotes fat breakdown in the liver, which is why retatrutide may produce even greater weight loss than dual agonists.
In Phase 2 trials, participants on the highest dose lost up to 24.2% of their body weight over 48 weeks — the most of any obesity drug tested to date.
Who is it for?
Retatrutide is not yet approved anywhere. It's currently in Phase 3 clinical trials (the final stage before regulatory review). If approved, it would likely be prescribed for:
- Adults with obesity (BMI ≥30) or overweight with comorbidities
- Type 2 diabetes (separate trials are underway)
- Non-alcoholic fatty liver disease (NAFLD/MASH) — early data shows significant liver fat reduction
How it's taken
In clinical trials, retatrutide is administered as a weekly subcutaneous injection with doses escalated from 1 mg to up to 12 mg over several months. Final dosing recommendations will depend on Phase 3 results.
Availability in India
Retatrutide is not yet available in India or anywhere else. Phase 3 trials are ongoing as of 2026. If results are positive, regulatory approval could come in 2027–2028. It is being developed by Eli Lilly.
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How is retatrutide different from tirzepatide?
Tirzepatide targets two receptors (GIP + GLP-1). Retatrutide targets three (GIP + GLP-1 + glucagon). The added glucagon activity increases energy expenditure and fat breakdown, potentially producing more weight loss. Phase 2 data showed 24% vs tirzepatide's 22%.
When will retatrutide be available?
Retatrutide is currently in Phase 3 clinical trials. If results are positive, regulatory submissions could happen in late 2027, with potential approval in 2027–2028. India availability would likely follow later.
What are the main side effects so far?
Phase 2 data shows GI side effects similar to other GLP-1 drugs — nausea, diarrhoea, vomiting. The glucagon component may cause a slight increase in heart rate. Long-term safety data is not yet available.
Does retatrutide help with fatty liver?
Early data is very promising. Phase 2 results showed significant reductions in liver fat in participants with NAFLD. Dedicated MASH trials are underway.
How it works in your body
Retatrutide activates three receptor systems simultaneously: GLP-1 (appetite reduction, insulin release), GIP (enhanced insulin sensitivity, fat metabolism), and glucagon (increased energy expenditure, hepatic fat oxidation, glycogen mobilisation). The glucagon component is what differentiates it from tirzepatide.
Phase 2 trial data
- Weight loss: 24.2% at 12 mg dose over 48 weeks (vs 2.1% placebo)
- Liver fat: Significant reduction — potential MASH treatment
- HbA1c: Reductions comparable to tirzepatide in diabetes sub-study
- Heart rate: Small increase (2–4 bpm) attributed to glucagon activity
What's next
Phase 3 trials (TRIUMPH programme) are enrolling now. Key trials include obesity, type 2 diabetes, and MASH indications. Results expected 2027.
Side effects & safety
Based on Phase 2 data only — the full safety profile will be clearer after Phase 3 results.
- Nausea — 25–45% depending on dose (higher doses = more nausea)
- Diarrhoea — 20–35%
- Vomiting — 10–20%
- Heart rate increase — 2–4 bpm on average (from glucagon activity)
- Decreased appetite — very common (therapeutic effect)
Retatrutide is experimental. Phase 2 trials are small (hundreds of participants). Phase 3 trials (thousands of participants, longer duration) will provide much clearer safety data. The same class warnings for pancreatitis and thyroid C-cell tumours apply to all GLP-1-containing drugs.
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