A retatrutide tracker, with the status stated plainly

Retatrutide is Eli Lilly's triple agonist, acting on the GLP-1, GIP and glucagon receptors. It produced the largest weight loss of any drug in a phase 3 obesity trial: 25.0 percent over 80 weeks at 12 mg in TRIUMPH-1, against 3.9 percent on placebo, counting everyone randomised (NEJM, September 2026). The 28.3 percent figure Lilly announced in May 2026 counts only people who stayed on the drug. It is not approved by the FDA or any other regulator. Lilly said in July 2026 that it plans to submit to the FDA in the first quarter of 2027, which puts any approval in late 2027 or 2028.

That means anyone outside a trial who has retatrutide has a research chemical from an unregulated seller, with no guarantee of what is in the vial. Peptide AI does not sell, source or recommend it. The compound is in the library because people log it, and because a log is safer than no log.

What the trials used

In TRIUMPH-2, people with type 2 diabetes lost about 21 percent at the top dose with HbA1c reductions of 1.4 to 1.6 points. Diarrhoea was the most reported side effect, at around 30 percent on the higher doses in TRIUMPH-3. Heart rate increases were larger than with semaglutide or tirzepatide in the phase 2 data, which is one reason the trials monitor it closely.

What to log

• The dose, in milligrams and in units. Research vials arrive as a powder and the concentration after reconstitution decides the units. The free retatrutide reconstitution calculator does the maths; the vial row in the app tracks doses left and the date mixed.
• Resting heart rate, daily, from the watch. This is the signal the trials watch. On Premium it comes from Oura, WHOOP, Garmin, Apple Health or Health Connect; on the free tier, type it in.
• Side effects as notes on the dose, with severity. Diarrhoea and nausea are the common ones.
• Weight, weekly.
• The source and batch, in the vial notes, so a reaction can be traced.

Setting it up in Peptide AI

1. Add Retatrutide from the compound library. The unit and the weekly schedule are already set.
2. Enter the titration your prescriber gave you. The app shows which week of which step you are on and when the next step is due.
3. Add the pen or vial, with doses remaining and the expiry date. A refill reminder fires at three doses left.
4. Note in the compound that this is a research protocol, so the log and any export say what it is.
5. Log each dose when you take it, with the site. Notes for side effects go on the dose.

When it is approved

The label will set the ladder, the missed dose rule and the warnings, and this page will change to match. Until then the retatrutide compound page carries the research status, and the approved alternatives are on the tirzepatide and semaglutide pages.

Logging on Peptide AI is free, and that includes GLP-1s. The dose log, the titration schedule, vials with doses remaining, injection sites with a rotation reminder, nutrition, supplements and training are all on the free tier with no card. Premium adds bloodwork, Oura, WHOOP, Garmin, Apple Health and Health Connect on the same timeline, the body scanner and Remi, the coach that answers from your own log. The pricing page has the three plans.