Retatrutide: what it is and what the research says

01

What it's made of

39Blocks

Y[Aib]QGTFTSDYSI[αMeL]LDK[K*]AQ[Aib]AFIEYLLEGGPSSGAPPPS

Lab-made block, not one of the 20FATFat tail: a fatty chain attached here makes it last about a week.

39 blocks, including 3 lab-made blocks that are not among the 20, plus a fatty tail that makes it last about a week.

Load it in the Peptide builder →

02

Where it comes from

Designed in a lab by Eli Lilly. The older weight-loss drugs hit one switch (semaglutide) or two (tirzepatide). Retatrutide adds a third: glucagon.

03

What it's studied for

● Proven in humans
Weight loss: in the TRIUMPH-1 phase 3 trial (2,339 people, 80 weeks, published in NEJM in September 2026), average weight loss was 17.6% to 25.0% depending on dose, versus 3.9% on placebo.
● Proven in humans
Type 2 diabetes: in TRIUMPH-2 (1,152 people, published in The Lancet in September 2026), weight loss was 11.9% to 18.8% depending on dose, versus 5.1% on placebo, and long-term blood sugar (A1C) fell by up to 1.6 points.
◐ Reported
Liver fat: in a smaller phase 2 study (about 100 people, 48 weeks), fat inside the liver fell by about half, up to more than 80% at higher doses, versus about 5% on placebo.
◐ Reported
Also being studied for knee osteoarthritis pain and sleep apnea.

Studied for ≠ proven to work. Check the stamp.

04

What we don't know

?
The first two phase 3 papers came out in September 2026, in NEJM and The Lancet. Both trials were run and paid for by Lilly, and no heart outcomes trial has reported yet.
?
◐ Reported
Heart safety: the number of serious heart events was similar to placebo (27 versus 23), but too small to be sure either way.
?
Like other drugs in this family, stomach side effects such as nausea are common.

05

Status

Not approved anywhere yet. Lilly plans to file with the US FDA in early 2027.
Not registered in Vietnam.
The US FDA has warned people against buying it from unapproved sellers.

06

Episodes

EP 05 · THE LOCK JOBStart with the problem Watch ▶

EP 14 · IT CAME FROM THE STACKCan you mix peptides? It came from the stack Watch ▶

07

Words to know

Agonist = Something that switches a receptor on.Phase 3 = The large human trials that come right before a drug can be approved.A1C = A blood test that shows your average blood sugar over about 3 months.

08

Sources

Checked: 9 Oct 2026

RETATRUTIDE