For the first one, I assume you mean a systematic review, not a peer review? I guess you're talking about this one:

https://pmc.ncbi.nlm.nih.gov/articles/PMC10180699/

It has a Mechanism section which explains that when collagen is digested, one of the products of that is Gly-Pro-Hyp, which is what has the effects. I don't think that conflicts anything in this post?

▲ staticassertion 3 hours ago | parent [-]

I assume they're referring to the brief bit in the post that indicates that oral ingestion leads to a breakdown that makes oral supplements of amino acids pointless. They say it very briefly and they don't really outright assert it, it's just a sort of implied aside.

▲ throwaway2037 2 hours ago | parent | next [-]

Here is the exact quote:

    > You’re not going to be taking these things orally... These mail-order peptides are injectable items.

Every single YouTube video and blog post I have read about peptites is exclusively about injectable supplements.

	▲	staticassertion 19 minutes ago \| parent [-]
		That's not the exact quote lol you cut out the exact part I was referring to. > because unless a really substantial amount of engineering has gone into it, any given peptide is going get the same treatment from your digestive system as a chicken breast does, i.e. a complete teardown > Every single YouTube video and blog post I have read about peptites is exclusively about injectable supplements. Collagen peptides, ghk-cu, and many other peptide supplements are often taken orally.

▲ A_D_E_P_T 2 hours ago | parent | prev [-]

Sweeping statements in biochemistry must be made with caution. It is well known that there are some small peptides that are absorbed following oral administration.

...BPC-157 itself is said to be among this class. As are certain milk tripeptides: https://en.wikipedia.org/wiki/Lactotripeptides

Interestingly enough, those two, as well as Gly-Pro-Hyp, are proline/hydroxyproline-rich, which might suggest that proline-rich small peptides are resistant to degradation in the gut.

Anyway, in general oral proteins and peptides are broken down prior to systemic absorption, but not always...

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oa335 42 minutes ago | parent | next [-]

> It is well known that there are some small peptides that are absorbed following oral administration. ...BPC-157 itself is said to be among this class

Do you know of any studies that suggest BPC-157 absorption from gut?

	▲	A_D_E_P_T 18 minutes ago \| parent [-]
		https://onlinelibrary.wiley.com/doi/abs/10.1002/jor.21107 Among others. If you read the paper, it's actually apparent that there's little difference between i.p. and oral administration in terms of efficacy -- both were roughly equally effective in improving MCL ligament healing. Admittedly the paper's in rats -- as are 99% of the others -- as there's no incentive for anybody to run human trials.

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staticassertion 2 hours ago | parent | prev [-]

I'm in agreement. It's the article that made the sweeping statement.