Retatrutide side effects and dosing schedule
This is what the TRIUMPH phase 3 trials actually recorded for retatrutide's side effects and dose-escalation protocol — not personal dosing advice, and not a guide to using any unlicensed product. Retatrutide is not licensed in the UK; see the main status page for what that means and why.
The TRIUMPH dose-escalation protocol
All TRIUMPH phase 3 participants started at the same low dose and stepped up on a fixed schedule, reaching the highest tested dose at around four months. This is the published trial protocol, not a recommendation — there is no licensed UK retatrutide product for anyone to actually follow this schedule with.
Side effects reported in the TRIUMPH trials
Figures below are trial-reported rates at the highest tested dose (12mg) unless stated otherwise. These are results from controlled trials with medical monitoring, not a safety profile for an unsupervised, unlicensed product bought online.
| Effect | Rate at 12mg (TRIUMPH-1) | Pattern |
|---|---|---|
| Nausea | 42.4% | Most common single effect; concentrated in the escalation period |
| Diarrhoea | 32.0% | Also reported at 30.1% (9mg) and 24.4% (12mg) in TRIUMPH-2/3 |
| Constipation | 26.1% | Reported alongside diarrhoea in the same participants at different points |
| Vomiting | 25.3% | Generally tracks with nausea severity |
| Dysesthesia (skin tingling) | 12.5% | A less common effect flagged as notable because it is not typically seen with dual GLP-1/GIP agonists |
Discontinuation by dose
Higher doses produced both stronger results and higher drop-out rates due to side effects — the trials themselves show this trade-off directly.
4.1%
Below the 4.9% placebo discontinuation rate6.9%
11.3%
13.5%
vs 4.8% on placeboWhat this page will not do
Retatrutide is not licensed in the UK. The only lawful way to receive it is as a participant in an authorised clinical trial, under medical supervision that includes exactly this kind of side-effect monitoring.