Retatrutide has gone from an obscure development code to one of the most talked-about peptides in the world. Here’s what it is, what clinical trials have reported, and what that does and doesn’t tell you.
Retatrutide is a synthetic peptide that activates three receptors at once: the GLP-1 receptor, the GIP receptor and the glucagon receptor. That is why it is called a triple agonist. These receptors are involved in appetite, blood-sugar control and energy use. It was developed by Eli Lilly under the code LY3437943, and in clinical trials it has been given as a once-weekly injection under medical supervision.1
“Reta” is online shorthand. “GLP-3” is slang for “three receptors” and is not a recognised drug class.
Everything in this section comes from sponsor-run trials of Lilly’s pharmaceutical product, not from research-grade material.
Phase 3 results are not yet peer-reviewed. They are the sponsor’s topline announcements, with full publications to follow. The headline figures assume participants stayed on treatment; the all-participants figures are lower.
The most common effects were gastrointestinal — nausea, diarrhoea, constipation and vomiting — along with reduced appetite. In TRIUMPH-1, nausea occurred in 42.4% of the 12 mg group versus 14.8% on placebo, and dysesthesia (unusual skin sensations such as tingling or altered touch) in 12.5% versus 0.9%. In that group, 11.3% stopped treatment because of adverse events, versus 4.9% on placebo.3
Research use only. Our vials are supplied for laboratory research. Nothing on this page is a claim about what retatrutide does in people, and nothing here is medical advice.
Independent testing programs have repeatedly found that a meaningful share of research peptide samples on the market fail on purity, identity, or labelled quantity — most often quantity, where the material is clean but there’s simply less of it than the label claims.
Prices for research-grade retatrutide vary widely across sellers, which makes independent testing the only real check on identity and labelled quantity. A certificate of analysis (COA) from the manufacturer is a starting point, not proof; independent testing after a batch arrives is the only way to know what is actually in a vial. Our approach is described in how we source and test.
Supplied as a lyophilised (freeze-dried) 10mg vial, reconstituted by the lab with bacteriostatic water before use. Bacteriostatic water is sold separately.
Freeze-dried peptide is far more stable than reconstituted solution. Keep vials away from heat and direct light; refrigerate once reconstituted rather than leaving it at room temperature.
An agonist activates a receptor. Retatrutide activates three: GLP-1, GIP and glucagon. Single- and dual-agonist peptides activate one or two of them.
No. It is an investigational medicine and has not been approved by the FDA. The developer says it plans to submit in the first quarter of 2027. Research-grade material is a laboratory product, not a medicine.
No. Trial results describe Lilly’s manufactured product given under medical supervision. Research-grade material is not equivalent to it and carries none of its manufacturing controls.
Published phase 2 trials and sponsor-announced phase 3 topline results reported large average body-weight changes alongside common gastrointestinal effects. Details and sources are above; phase 3 data are not yet peer-reviewed.
Keep lyophilised peptide cool, dark, and dry; refrigerate reconstituted solution rather than storing it at room temperature.
Supplied lyophilised for laboratory research. Sold by the bottle, not the ten-unit kit.
Shop retatrutide