Retatrutide step-up, the early study plan behind TRIUMPH-1

Weight loss with an experimental drug that acts on three gut hormone signals

The schedule a registered study in people actually used, taken from the paper and the study's public registration, not from a label summary. Every one links a PubMed or ClinicalTrials record you can open.

Not advice. This is a record of a schedule, not a dose for you.

The schedule, as reported

Each field below is what the source states, not a rounded version of it. Where the source does not publish a detail, the field says so instead of filling the gap.

Amount: 1 mg, 4 mg, 8 mg or 12 mg as the ongoing dose, from a starting dose of either 2 mg or 4 mg
How often: Once weekly
How it is taken: Shot under the skin
How long: 48 weeks in the mid-stage study. The large final-stage TRIUMPH-1 ran 80 weeks, plus a further 24 week extension.

How it was reached, step by step

01
People were split by chance, in set proportions (2:1:1:1:1:2:2), into one of six retatrutide groups or a dummy shot group
02
The groups were 1 mg, 4 mg from a 2 mg start, 4 mg from a 4 mg start, 8 mg from a 2 mg start, 8 mg from a 4 mg start, and 12 mg from a 2 mg start
03
One shot under the skin each week for 48 weeks
04
The published report does not give the week by week step timings, so they are not written here

What was measured

The main thing measured: how much body weight changed, in percent, from the start to 24 weeks. Also measured: the change at 48 weeks, and how many people lost 5, 10 and 15 percent. Safety, gut side effects and heart rate were checked.

What was reported

Results as the study reported them, with what they were compared against.

At 24 weeks, average weight loss was 7.2 percent on 1 mg, 12.9 percent on the 4 mg groups together, 17.3 percent on the 8 mg groups together and 17.5 percent on 12 mg, against 1.6 percent on the dummy shot.
At 48 weeks it was 8.7 percent, 17.1 percent, 22.8 percent and 24.2 percent, against 2.1 percent on the dummy shot.
At 48 weeks, 60 percent of the 4 mg group, 75 percent of the 8 mg group and 83 percent of the 12 mg group had lost at least 15 percent, against 2 percent on the dummy shot.
Gut side effects rose with the dose and were mostly mild to moderate. Starting at 2 mg instead of 4 mg cut them somewhat. That is why the starting dose was also assigned by chance.
Heart rate rose more at higher doses, peaked at 24 weeks and came down after that.

Where this comes from

Jastreboff et al., Triple-Hormone-Receptor Agonist Retatrutide for Obesity, A Phase 2 Trial, New England Journal of Medicine, 2023. 338 adults, paid for by Eli Lilly.

The public registration for the large final-stage TRIUMPH-1 study calls its groups Dose 1, Dose 2 and Dose 3, and does not give the milligram amounts. So the only retatrutide dosing plan on public record with amounts is the mid-stage one written above. Anyone quoting a TRIUMPH-1 dose is quoting something the registry does not say.

What this protocol cannot tell you

Required on every entry in this registry, and never empty.

Retatrutide is not approved anywhere, for anything. Every milligram figure above comes from a mid-stage study of 338 people whose main result was at 24 weeks. Doses at that stage are picked to find the range, not to be the right dose. The registry does not publish the final-stage doses, so nobody outside Lilly can say what the study that reported 28.3 percent actually gave. Heart rate rose with the dose. Anything sold as retatrutide is not made by Lilly, and nothing checks what it is or what is in it.

The compounds in this protocol

Each profile has the full evidence record, the legal status and what the studies did not show.

RetatrutideStrong. At least two finished studies in people, and at least 1,000 people who took it. 5 completed trials, 1,345 people given it.8 reported
A weekly shot that is still being tested. It works on three hunger and blood sugar signals. It has led to the most weight loss of any drug in studies so far.

Other trial protocols in the registry

All protocols