Pipeline · TRIUMPH-1, 21 May 2026
Retatrutide: above 28% weight loss, and not available
On 21 May 2026 Eli Lilly reported positive topline results from TRIUMPH-1, the pivotal Phase 3 obesity trial of retatrutide, with weight loss above 28% — the highest figure yet from a GLP-1-class agent. Retatrutide is not approved, not available by prescription, and anything currently sold under that name is not the trial drug.
What retatrutide is
A triple agonist targeting the GLP-1, GIP and glucagon receptors. Semaglutide hits one of those, tirzepatide two. The glucagon arm is the addition, and the >28% topline is why the drug has drawn the attention it has.
The part that matters most right now
Because the results are public and the drug is not, demand has appeared for something called retatrutide — and a grey market moved to meet it. This is the most dangerous thing happening in this niche.
An investigational molecule has no approved labelling, no established dose, no approved manufacturing standard and no safety monitoring outside a trial. A vial from a research-peptide seller is not a medicine: nobody has established what is in it, at what purity, or what dose is appropriate — that is what the trials are for. "Not for human consumption" is not a formality to work around.
No legitimate program in our database offers retatrutide, and a program that did would be disqualifying rather than innovative. Connecticut's attorney general has announced enforcement against an overseas platform selling "research grade" GLP-1s into the US; see that story.
What happens next
Positive topline results begin a regulatory process, they do not end one. Full data, publication, submission and review all sit between a topline announcement and a prescription. Any site quoting you a launch date is guessing.
Meanwhile
The approved options are what exist now, and our price database covers what they cost — the compounded tirzepatide floor is currently $169 a month all-in. Waiting for an unapproved drug while doing nothing is itself a decision with consequences, and one to discuss with a clinician rather than a comparison site.
Verified . Regulatory positions, prices and trial results move — check the primary source before relying on a date. Compounded tirzepatide and semaglutide are not FDA-approved products.
Questions
Is retatrutide approved?
No. Eli Lilly reported positive topline Phase 3 results from TRIUMPH-1 on 21 May 2026 with weight loss above 28%. It remains investigational and is not available by prescription.
Can I buy compounded retatrutide?
Products sold under that name exist and are not the trial drug. An investigational molecule has no approved labelling, established dose, approved manufacturing standard or safety monitoring outside a trial. No program in our database offers it.
How much weight loss does retatrutide produce?
Above 28% in the TRIUMPH-1 pivotal Phase 3 obesity trial per topline results reported on 21 May 2026 — the highest reported in this drug class to date.
When will retatrutide be available?
No date has been announced. Topline results precede full data, publication, regulatory submission and review.