Mel II is has basically been approved by the FDA in the US and its equivalent in Australia.
There really aren't any long term side effects noted.
The main reason you haven't heard about it from them is the pharma companies would love to market but can't see a way to dose it with out injection.
It got a lot of press pre Viagra as the "barbi drug", but since the only way to use it is sub q, it has fallen off the screen.
Its still being researched in women because it is the only drug besides testosterone that is proven to increase the female libido.