I won't comment on topical collagen as there is indeed reasons why it may work but we can be pretty sure oral supplementation is unnecessary, since it is just a protein, so if you get sufficient protein intakes (of the respective amino acids) then your body will just make it. Your body when digesting collagen (and other proteins) in almost all cases will just convert it into it's amino acids anyway. The supplement industry is just EXTREMRLY profitable and so distorts modern media and occasionally science.