There is a chinese herb called He su wu or Foti root which is alleged to have remarkable powers. google it
Aternatively Vedic stuff wot duz work is Ashwaganda( the Hindi version of goosey) and Shilajit, mixed with maca and Reishi mushroom
I make my own capsules, getting the product from Tree Harvest.co.uk , an organic importer in Devon. they are also good for general good health and keeping you feeling a little younger than your age
I dont rate the off the shelf herbal stuff from the likes of Holland and Barrett.
Viagra however, is easier to obtain.