TB-500 and thymosin beta-4: the fragment versus the protein

TB-500 and thymosin beta-4: the fragment versus the protein Writing it up because I had to work it out twice and would rather nobody else did.

I have seen SURPASS-4 (Lancet, 2021) 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.

Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the kind that comes from remembering a figure instead of looking it up.

This follows post #10 rather than contradicting it.

For anyone arriving from search engines: this subcategory discusses published preclinical work and the absence of published clinical work. It does not endorse or recommend these compounds.

Worth separating two things that post #34 runs together.

Reading a preclinical wound-healing model: the model shows whether a mechanism is plausible in a specific context. It does not show magnitude of effect in humans, does not show safety profile in humans, and does not show whether the effect survives in a more complex biological system. That is not a criticism of preclinical work — it is what preclinical work is for.

The distinction between "no evidence it works" and "evidence it does not work": we have the first for these compounds. That is genuinely different from the second and the distinction matters, but it also means treatment plans based on these compounds are being built on theoretical grounds, not empirical ones.

BPC-157: the preclinical literature is extensive, mostly from a small number of research groups, and reports effects across a wide range of injury models. The breadth of reported effects is itself worth noting — a compound that improves outcomes in tendon, muscle, gut, nerve and bone through a single mechanism would be remarkable, and remarkable claims deserve proportionate scrutiny.

For anyone arriving from search engines: this subcategory discusses published preclinical work and the absence of published clinical work. It does not endorse or recommend these compounds.

Reading a preclinical wound-healing model: the model shows whether a mechanism is plausible in a specific context. It does not show magnitude of effect in humans, does not show safety profile in humans, and does not show whether the effect survives in a more complex biological system. That is not a criticism of preclinical work — it is what preclinical work is for.

post #108 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.