It's becoming quite usual that people older than ¿30-40? years old complement their diet with collagen for bones and specially articulations-related issues. I know some of them which use it as a preventive method.

My doubt arises when thinking that it's just a protein molecule, so as far as I know it will be subdivided into amino acids before reaching our bloodstream.

Since these amino acids are so ordinary and can be found in so many nutrients aside from collagen molecules, what's the point of ingesting pure collagen? Would it be really useful or completely unnecessary?

PD: Since the comment where I said it has "disappeared" I want to thank here @Nate Barbettini his appropriate help.


2 Answers 2


Collagen is not an easy-to-digest protein and generally requires collagenase for efficient digestion. Without digestion, it cannot be absorbed. Moreover, collagen has to be deposited in the right site.

So irrespective of whether collagen is completely digested or not, it cannot be specifically useful for replacing the lost collagen in the joints.

There are two modified amino acids in collagen- hydroxyproline and hydroxylysine, which are essential for the structural integrity of the protein. Vitamin-C is involved in natural production of these amino acids in the body from the unmodified amino acids and hence the deficiency of Vit-C results in scurvy.

Hydroxyproline and hydroxylysine, given as supplements may have some positive effects in healing of injuries [ref] (I am not too sure about this). In general, a good diet would be sufficient and talking collagen as a supplement is, IMO, not useful.


I had thought that collagen was about the same as chondroitin and glucosamine, in that there wasn't much evidence to support the notion that it is a viable supplement.

However, when I went looking for some studies on it, I was surprised, in that there are several studies that show improvement in articulation (movement at a joint) and pain, especially in arthritic and injury affected people.

This study was done over 24 weeks, with athletes suffering from joint pain, and there was a marked improvement across the cohort (97 usable athletes out of 147 selected) in several pain and inflammation markers.

A second study also showed marked improvement in pain and quality of life in osteoarthritis sufferers using undenatured collagen (type II).

These studies as well as the two others that I have linked without summation, suggest that collagen supplements have a healing effect when injured or suffering from degenerative disease (Such as arthritis), however I was unable to find any studies focusing on prevention using collagen (Which is notoriously hard to prove, if they never get it, you don't know if it was the collagen or not).

Whey and Collagen effect on nitrogen balance

Arthritic pain in horses

  • Thank you for your input @JohnP, In fact that kind of studies are the ones that make many people buy and ingest collagen, but I can't understand why it is effective. My question is focused on how can this be physically possible (I'm not saying it isn't, I just would like to understand it). Commented Sep 8, 2015 at 2:29
  • I don't know the mechanism of action for it. The second study lists several studies that corroborate the efficacy of collagen, and a couple of those note no improvement with glucosamine/chondroitin. If I find one that delineates the mechanism, I'll edit my answer. I suspect that it isn't quite known what causes it yet, or hasn't been confirmed.
    – JohnP
    Commented Sep 8, 2015 at 3:29

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