I wonder, though, what the downsides are of this drug. If the human body can produce it and if there are only upsides, then why didn't evolution make the substance more abundantly available?
Things that cause growth are generally a very bad thing in biology, because they cause cancer. Look at a list of proteins key to cancer and you'll find tons of growth promoters, some of which have the word "growth" right there in the name (the G in EGFR, FGFR, VEGFR, IGFR).
Growth must be tightly regulated to not end up as cancer, so that's why it's not abundantly available.
The article makes the point that despite human trials originally, and later one-cell zebrafish embryo tests, no sign of carcinogenesis was detected. They further explain that given its limited range within the body, it only impacting damaged tissue and the short period of time it would be used, it’s unlikely to be carcinogenic.
Oh sure, this agrees with the "tightly regulated" constraint. Short time, localized application/expression qualify. I'm not sure that long term exposure would be good, and in reference to BPC-157 let's not forget that intestinal cancers do occur (though I'm not at all sure if there's ever been a link between BPC-157 and intestinal cancer).
It's great that the compound looks safe given the limited amount of information we have, but it sounds like there's not a whole lot of trials out there with the power to test the possibility that this could be cancerous long term. Happy to be proven wrong though!
Remember the initial human trials were using it systemically to control blood sugar, and specifically looked for carcinogenesis. Obviously there’s room for something to have been overlooked, but in the narrow case of this particular molecule I’d be hopeful. As for BPC-157 we’re very much on the same page, and I’d be very concerned about cancer.
I suppose that many of the injuries would not be survivable before modern medicine, even if that chemical were produced. Major wounds that take more than a few days to heal and impair the ability to hunt would be almost always fatal. Torn ligaments require surgery to properly reattach them.
I've heard this referred to as the "no free lunch" principle, and it's a good tool to apply to any claims about a new way to improve human performance.