As you mention, you want to market your ingredients through commission basis agent. There is no particular way to search for commission basis agent. You can advertise
like medical books or medical news papers for requirement of persons at commission basis. Most of persons who will work for you at commission basis, do work in somewhere and for part time income they start at commission basis. You have to build relationships to the marketing persons
who are already working for other nutraceutical ingredients company
. You have to offer them good profit
and secret their privacy. Few independent commission agents you can find but they will not help you lot because they work for many companies.