Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Synthetic triagonist peptide that simultaneously activates the GLP-1, GIP and glucagon receptors. Developed by Eli Lilly; in phase-3 trials for obesity (TRIUMPH programme) and type 2 diabetes. No marketing approval yet.
Researched for
Weight reduction in obesity (TRIUMPH programme)Glycaemic control in type 2 diabetesSteatotic liver disease (MASH)
Official status
US: Unapproved
No FDA approval. Phase-3 TRIUMPH programme is ongoing; an approval decision is expected no earlier than 2026/2027.
Retatrutide is a 39-amino-acid peptide with agonism at three incretin/energy-balance receptors: GLP-1R (insulin secretion, satiety), GIPR (insulin sensitivity, lipid metabolism) and the glucagon receptor (energy expenditure, lipolysis). The added glucagon activation is intended to raise catabolic energy expenditure while concurrent GLP-1/GIP action compensates the hyperglycaemic effect. Albumin binding via a fatty-acid side chain enables weekly dosing.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
4 observations · single evidence tier
Human RCT
4
03
What the studies show
Human RCT
Mensch
Jastreboff AM. et al. 2023
Weight reduction over 48 weeks observed in the phase-2 obesity trial — at the highest dose greater than documented for other incretin-based therapies
What does NOT follow: Phase-2 data; phase-3 results (TRIUMPH-1, -2, -3) not yet fully published. Long-term data beyond 1 year absent.
Human RCT
Mensch
Rosenstock J. et al. 2023
HbA1c reduction in type 2 diabetes over 36 weeks documented in a phase-2 trial
What does NOT follow: Effect size in phase 2; comparison with established GLP-1 RAs and GLP-1/GIP agonists in phase 3 pending.
Human RCT
Mensch
Reduction in liver fat (MRI-PDFF) in adults with obesity in a sub-analysis of the phase-2 obesity trial
What does NOT follow: Sub-analysis, not a primary endpoint; dedicated MASH trials are running.
Human RCT
Mensch
Jastreboff AM. et al. 2023
Gastrointestinal adverse events (nausea, vomiting, diarrhoea) were the most frequent events across all phase-2 trials
What does NOT follow: Profile similar to other incretin-based substances; often dose-dependent and transient.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 144 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Subcutaneous
In all phase-1 and phase-2 trials administered subcutaneously once weekly (abdomen, thigh, upper arm).
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human RCT
Nausea / vomiting
Most frequent events documented in the phase-2 trials; often transient in the titration phase.
häufig, dosisabhängig
Human RCT
Transient heart-rate increase
Possibly attributable to the glucagon component; class effect of incretin-based therapies includes a moderate HR rise.
in Phase-2-Daten beobachtet
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
08
Risks & hygiene aspects in the literature
What regulatory and scientific literature reports on risks, sterility and identity in non-pharmaceutical sources — descriptive, not a hygiene guide.
Early data, long observation pending
Phase-2 data published to date cover a maximum of 48 weeks. Cardiovascular outcomes, cancer risk and reproductive safety are being systematically captured in phase 3.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
In forums Retatrutide is already being labelled the 'most potent available' obesity peptide prior to market approval — partly with black-market distribution.
common in obesity and bodybuilding forums
Not supported by studies: Black-market versions outside clinical trials are not verified for identity, purity or endotoxin load. Phase-2 effect sizes arose under strict trial conditions — self-administration with unverified substance is not comparable.
11
Legal status by country
Country
Status
Note
Checked
United States
Unapproved
No FDA approval. Phase-3 TRIUMPH programme is ongoing; an approval decision is expected no earlier than 2026/2027.
2026-05-22
Germany
Unapproved
No EMA approval. Availability only within clinical trials.
2026-05-22
JP
Unapproved
Phase-3 trials are also conducted in Japan; no approval.
2026-05-22
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.