I don't see how it's possible in this age of technology, people don't realize they can objectively assess these things. Companies like Spectracell, Genova Diagnostics can test for about every micronutrient in your body that impacts hair growth the hair supplement companies put in their products. And you can find out via 23andme, Genetic Genie, if you can even metabolise many of these nutrients. But, as usual, there are profits to be made on the backs of fearful, desperate and ill-informed people.