Anything that promises to kill cancer cells, increase libido and even size of one's instrument is very suspect in my opinion - especially when there is a link to buying the product touted. Also, in the phrase - "Note that at least in vitro (tissue studies) this worked with head and neck cancer as well as other types" it appears that it has only been observed in vitro which seems to indicate it has not been tested in human trials. Before rushing out to buy Viagra for my Smoker Son in the hopes of killing any cancer cells he might be harboring in his body -I am going to wait for some more definitive study. JMO