There are many instances in the history of science where great pioneers and new scientific theories were met with resistance. William Harvey (nature of blood circulation), Joseph Lister (antiseptic technique) and Louis Pasteur (germ theory) are notable examples. Today's quacks boldly claim that they too are scientists ahead of their time. Close examination, however, will show how unlikely this is.

Galileo, Harvey, Lister, and Pasteur overcame opposition to their theories by demonstrating the soundness of their ideas with scientific evidence. They, and other scientists, built up such a large amount of supporting evidence that their peers just had to accept their ideas. Sooner or later, all new theories are proven or disproven by a build up of scientific evidence for or against them. Many theories of treatment for hair loss supported by snake oil sellers either have no supporting scientific evidence or there is evidence that directly refutes the theory.

There are many more instances in scientific history where new scientific theories were proved flawed or just plain wrong. The Federal Drug Administration (FDA) of the USA has investigated around 250,000 claims for products that regrow hair. All but three (minoxidil 2%, minoxidil 5%, Propecia) have been rejected as worthless.