Retatrutide

What the studies found

• The largest weight reduction reported for a drug to date

  A phase 2 trial published in the New England Journal of Medicine in 2023 reported mean weight loss of approximately 24% at 48 weeks at the highest dose, in 338 participants. Weight had not clearly plateaued when the trial ended.

• Phase 3 under way

  The TRIUMPH programme is running across obesity, type 2 diabetes, knee osteoarthritis and cardiovascular outcomes. Results are not yet available.

What the evidence does not show

• No phase 3 results have been published. Phase 2 findings frequently shrink at phase 3, and roughly a third of drugs entering phase 3 still fail.
• The phase 2 trial ran 48 weeks in 338 people. That is too small and too short to characterise uncommon adverse events.
• A dose-dependent increase in heart rate was observed. Its long-term significance is unknown.
• No approved dose exists, because no regulator has evaluated it.

Reported risks and adverse effects

• Gastrointestinal effects were the most common adverse events and were dose-related.
• Heart rate increased in a dose-dependent way in phase 2.
• The full adverse event profile is genuinely unknown — that is what phase 3 is for.
• Material sold outside clinical trials has no verified identity, purity or sterility, and no regulator is checking it.

This is a summary of what has been reported in the literature, not a complete safety profile. For anything concerning your own health, speak to a doctor.

Regulatory status

Not approved by any regulator anywhere in the world. It is an investigational product, legally available only through the clinical trials running it.