I can't make up my mind about this one: Catuaba.   It's an 'aphrodisiac infusion' from the Amazon... on the positive side, it has a persistent legend surrounding its efficacy at, er, 'doing what it says on the tin'.   It's not just sold to foreigners, but seems to be much praised in its location of origin.  There's even a song about it (I'd love to hear that!)   On the negative side, no-one can decide what the tree is that is supposed to be the 'real' Catuaba!   Rain Tree lists several trees that have been claimed to be Catuaba, aphrodisiacs-info has a similarly lengthy list.   I wish science would catch up... where is the funding for research into this?   Someone said that the Amazon jungle contains potentially more medicines than any other region.  Yet they still insist on cutting it all down before it can be investigated.
The other challenge is that I've read that there seems to be some bad behavior in the world of some of these products.   I think it was Muira Puama (?) where one batch was found to be sawdust from some other rainforest tree....