In the cosmetic dermal-filler market, bovine-derived collagen has been supplanted by human collagen even though the human-derived products are no more effective than the bovine ones. The reason: less risk of a serious allergic response and no need to pre-test for allergy.
Collagen dermal fillers have in turn been overtaken by Restylane (which is animal-free), but this is because Restylane works better and lasts longer.
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”