This topic is very interesting yet confusing. I have been taking just 1-2 tablespoonsful daily for several years now, even before diagnosis of op, for general 'antiaging' purposes. I use the most common brand 'Vital Proteins collagen peptides'. Over the years I was more convinced by one school of thoughts, that is, after ingesting these collagen peptides, they need to be broken down to single amino acids (even smaller molecules for other purposes) at molecular level in our body anyway then made into collagen by our own body! As we age, our body's natural ability to make quality collagen decrease. That's why almost everyone loses elasticity of skin, possibly bone matrices as we age.

Recently I bought simply tera's whey protein(bovine) to supplement my daily protein intake. When I put these two bottles of products ( whey protein and collagen peptides) side by side, I can see clearly both of them have all 9 essential amino acids. Whey protein has 18 amino acids while vital protein collagen has 19 amino acids. The stand out difference is Vital protein collagen peptides has hydroxylysine and hydroxyproline while whey protein doesn't. The composition or percentage of each amino acid are a bit different too. I think that is why, some medical professionals are saying that if one eats enough quality proteins including soft bones, cartilages and soft connective tissues etc, theoretically one would have enough neccessary amino acids to make collagens. Well I still take Vital protein collagen peptides for the fear of missing out that special amino acid(s) needed for building collagen.