Why retatrutide discussion here is more cautious than elsewhere

Why retatrutide discussion here is more cautious than elsewhere I have a specific reason for asking rather than idle curiosity, and the context is below.

I have seen SURMOUNT-OSA (N Engl J Med, 2024) cited in support of a claim I do not think it supports, twice this month, so I would like to work through what it actually shows.

My reading is that the trial is sound for its own question and is being stretched to answer a different one. I might be wrong about that, which is why this is a topic rather than a correction.

What I would like from this discussion: someone who disagrees with me to say why, with the section of the paper they are relying on.

Triple agonism: is the effect additive, synergistic, or neither? A phase 2 comparison of tirzepatide (dual) to retatrutide (triple) would answer that question. The published data does not include such a direct comparison.

I read the opening post twice before replying, because I had assumed the opposite.

Mass and identity: a report on retatrutide should state the mass detected by LC-MS, not assume a theoretical mass. The theoretical mass is not published in peer-reviewed literature for retatrutide at present.

TRIUMPH is phase 3 and it is ongoing. No phase 3 results exist. Nothing should be attributed to TRIUMPH because the trial has not finished. When it does, this page will update.

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

Coming back to post #5, because the follow-up matters more than the original answer.

Retatrutide is investigational. Anything obtained outside a trial is by definition research-use-only material with no human-use authorisation. This site will state that plainly rather than winking at it.

Picking up post #5: that is the part I would want checked first.

Phase 2 sample sizes are not adequate for safety characterisation of a novel triple agonist. Phase 3 is where that question gets answered. Using phase 2 results to make claims about safety profile is using the trial for a purpose it was not designed for.

Worth separating two things that post #5 runs together.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

post #9 is right about the mechanism and I think understates the practical bit.

The phase 2 obesity paper reported dose-dependent weight reduction of a magnitude that attracted attention. It also reported dose-dependent heart-rate increases. The heart-rate signal is the reason phase 3 exists rather than something assumed negligible based on phase 2.

post #10 answers the question as asked. The question underneath it is different.

What we do not know about retatrutide, listed explicitly: long-term safety, real-world response rates, the dose response in diverse populations, whether the heart-rate signal persists or attenuates, durability of effect on withdrawal, efficacy in comorbidities beyond obesity.

On post #8 — agreed on the reasoning, with one qualification.

Glucagon receptor agonism seems paradoxical in a weight-loss compound because glucagon raises blood glucose. The paradox resolves because glucagon agonism also increases energy expenditure and promotes hepatic fat oxidation, and the incretin components offset the glycaemic effect. In diabetes trials, HbA1c improved rather than worsened.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.