How long does it take for retatrutide to kick in?
Thirty-one of 36 retatrutide-treated participants in a phase 2 exit-interview study reported changes in eating behaviors within the trial's first 8 weeks; the sources give no exact day of onset.
Short answer
Thirty-one of 36 retatrutide-treated participants in a phase 2 exit-interview study reported changes in eating behaviors within the trial's first 8 weeks; the sources give no exact day of onset.[1]
What people in the trial noticed early
Those participants described eating smaller portions, feeling hungry less often, feeling full after meals and feeling more in control of their eating.[1]
In adults with type 2 diabetes, appetite, hunger and prospective food consumption were already reduced at week 24 versus placebo on retatrutide 4 mg or more.[2]
In the phase 1 single-dose study, a reduction in body weight was still present up to day 43 after a single dose.[3]
When the scale moved in the phase 2 obesity trial
The phase 2 obesity trial made the 24-week point its main weight readout, and by then the 12 mg group had lost 17.5% of body weight against 1.6% on placebo.[4]
More questions on Retatrutide
More on Retatrutide
Sources
- 1Perceived benefits of treatment for obesity with retatrutide: A qualitative study of patients in a phase 2 clinical trial.Obesity pillars · 2025PMID 41216380Accessed 2 Oct 2026
- 2Appetite, eating attitudes, and eating behaviours during treatment with retatrutide in adults with type 2 diabetes: Results of a phase 2 study.Diabetes, obesity & metabolism · 2025PMID 40916752Accessed 2 Oct 2026
- 3LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept.Cell metabolism · 2022PMID 35985340Accessed 2 Oct 2026
- 4Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial.The New England journal of medicine · 2023PMID 37366315Accessed 2 Oct 2026
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