Why plausible mechanism is not evidence of effect — one year on

The question in the title: Why plausible mechanism is not evidence of effect — one year on I will give what I have already checked below so nobody repeats it.

Session topic: STEP 4 (JAMA, 2021). Please read it before posting; the discussion is much better when everyone has.

The question I would like us to start with is what the trial set out to estimate, rather than what it found. Once that is on the table we can talk about whether the design could have answered it, and only then about the numbers.

Specific things I would like covered: the population and how far it generalises, how discontinuation was handled, whether the comparator was a fair one, and what the absolute rather than relative effect looks like.

I will summarise at the end and the summary will feed the relevant digest page.

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.

TB-500 is usually the 7-residue actin-binding fragment of thymosin beta-4, not the full 43-residue protein. The two are routinely conflated in supplier documentation and in the literature. Evidence about the full protein does not automatically apply to the fragment.

The absence of adequately powered published randomised human trials is the central fact about BPC-157. This site states that plainly rather than hedging. Mechanistic plausibility does not substitute for it.

Why plausible mechanism is not evidence of effect: a mechanism that is chemically or biologically plausible can fail in practice for dozens of reasons — bioavailability, off-target effects, metabolism, clearance, or simply that the mechanism does not do what the theory predicts in a living system. Plausibility is necessary for hope but not sufficient for evidence.

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

post #7 answers the question as asked. The question underneath it is different.

Stability of BPC-157 in solution: what has been measured in published work covers specific formulations under specific conditions. Extrapolating to a reconstituted preparation in a different diluent at a different concentration is an extrapolation, acknowledged as one.