Could you provide you literature citations here for reference?
...what, lmao
1. Collagen is not an amino acid, it is a protein
2. The body makes a lot of things itself that we supply to sick or wounded people. It is SOP in any hospital to supply: various proteins, heat, enzymes, clotting factors, blood, hormones, steroids that the body makes itself... "The body makes (thing) itself" is an absurd reason not to supply something to the wounded. It does not make one iota of sense if you have even the slightest knowledge of medicine.
3. "Also you get the same type of amino acid by eating jello pudding." Yes, and you get salt and water from McDonalds fries, and yet we still use saline solution. Jerusalem artichokes are high in inulin, which we also use to measure kidney function. Why exactly would any of this have any bearing on its efficacy? Collagen, by the way, is the most abundant protein in mammals, so there are a long list of things aside from Jello that contain it.
4. Sterile collagen is widely available both OTC and to professionals
5. Sure. Here's a review of eleven RCTs on collagen dressings for wound healing. Pretty powerful results! doi:10.3389/fsurg.2022.978407