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Peptideworth

Head-to-head

Two compounds, searched together

These pairs get typed into search side by side far more often than any trial program has ever tested them side by side. Each page below shows what each compound’s own trials actually found — same population, same duration, same phase, laid out so you can see where the comparison is honest and where it isn’t.

Comparisons

1

Compounds covered

2

The comparisons

Retatrutide vs. Tirzepatide

Retatrutide's phase 2 obesity trial reported a larger average weight loss than tirzepatide's phase 3 approval trial, which makes it tempting to read this as a contest retatrutide already won. It isn't one, because it is not a head-to-head comparison. A trial putting the two drugs in the same study is registered — NCT06662383, listed enrollment 800, listed completion December 2026 — but as of August 2026 a PubMed search for retatrutide returns no published trial that randomized participants to one drug or the other, so every figure below comes from a separate trial on a different population for a different duration at a very different scale. Retatrutide has also now reported a phase 3 result of its own, in type 2 diabetes, and it is not an approved medicine of any kind, while tirzepatide is FDA-approved and available by prescription as Zepbound and Mounjaro. This page lays out what each trial actually reported, not what stacking the headline percentages next to each other would imply.

Retatrutide

Randomized trials

Evidence strength: Randomized trials. Randomized controlled trials in humans, at scale.

Tirzepatide

Randomized trials

Evidence strength: Randomized trials. Randomized controlled trials in humans, at scale.

Looking for one compound instead?

The peptide index goes deep on one molecule at a time, and peptides by goal ranks every compound against one outcome. How the evidence tiers shown above are set is on our methodology page.

Medical disclaimer: This content is for general educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a licensed healthcare professional before starting, stopping, or changing any treatment.