Side effects

This is a bit of a roundabout ramble so please bear with me a bit. I was reading an article today about Latisse, the eyelash-growing medication that Brooke Shields talks about on television. The article was pointing out how people know about the wacky side effects (like darkening your eye color or making hair grow other places on your body if you accidentally drop some on you), yet they still use the product. For the most part, they just don't care. They want those luscious eyelashes so badly that they will risk the side effects. I wonder if this is true to weight loss pills. That people know the side effects, but they are so determined to shed those pounds that they take the pills anyway. Where does one draw the line? How bad does something have to be before you'll pass on it?