comment: >
  
  Why would anyone volunteer though? So it doesn't happen to animals?
context: Many years ago a girl I knew volunteered for testing instead of animals. She lost all of her eyelashes when testing a mascara. >
  
  Ugh, why would that be a volunteer thing? At least clinical trials almost always compensate you with cash. >
  
  Simply because of the paper work and beaurocracy required to perform a clinical trial. Therefore the cosmetic industry run "volunteer studies". They still require ethics etc. but you can set up your own ethics committee and pass off your own experimental protocols.