EP 142:16

Retatrutide's big trials, published: what TRIUMPH-1 and TRIUMPH-2 found

Name: Retatrutide's big trials, published: what TRIUMPH-1 and TRIUMPH-2 found
Uploaded: 2026-09-28
Duration: 2 min 16 s
Description: On 29 September 2026 retatrutide's two big phase 3 trials were published the same day. What TRIUMPH-1 and TRIUMPH-2 found, what changed with peer review, the side effects, and why it still isn't approved.

On 29 September 2026 retatrutide's two big phase 3 trials were published the same day. What TRIUMPH-1 and TRIUMPH-2 found, what changed with peer review, the side effects, and why it still isn't approved.

Transcript and sources

Retatrutide just landed in two top journals, on the same day. Here's what the trials actually found.
On September twenty-ninth, TRIUMPH-1 was published in the New England Journal of Medicine, and TRIUMPH-2 in The Lancet. Both lasted eighty weeks, were double-blind, and compared three doses with placebo.
TRIUMPH-1 enrolled two thousand three hundred and thirty-nine people with obesity but no diabetes. TRIUMPH-2 enrolled one thousand one hundred and fifty-two people with obesity and type 2 diabetes.
In TRIUMPH-1, the top dose averaged twenty-five percent weight loss, counting everyone who started, versus three point nine percent on placebo.
In people with diabetes, the top dose averaged eighteen point eight percent, versus five point one on placebo. Same drug, same eighty weeks: people with diabetes lost less.
Those journal numbers matched what Lilly had announced months earlier. What changed is that they've now been through peer review. Both trials were funded by Eli Lilly, which makes retatrutide.
There were knock-on effects. In people with sleep apnea, breathing pauses fell by about thirty-four an hour, versus about ten on placebo. And in people with diabetes, the blood-sugar measure A1C fell by about one and a half points.
Nausea and diarrhea were the most common side effects. In the diabetes trial, twenty-eight percent on the top dose had nausea, versus eight percent on placebo. Up to seven percent reported odd skin sensations, called dysesthesia, and up to twelve percent stopped the drug because of side effects.
What these papers don't show: fewer heart attacks or strokes, or how it compares with tirzepatide. That head-to-head trial hasn't reported.
And peer review isn't approval. Retatrutide still isn't approved anywhere. Lilly plans to apply to the FDA in early 2027.
Two journals, one day, and still a lot to learn. Every number is at peplexicon.com.

Sources