I'll confirm what funkymoped says - they do 'just work' because they have a physical effect, viz. to increase the blood pressure and thus increase the flow of blood to the p***s (not sure if the censor will strike that out). Obviously, the more the desire, the longer it stays in place, so to speak.
The gel version works in about fifteen or twenty minutes and can still be effective next morning.
Viagra and Horlicks are often given to men in old folks homes at night. The Horlicks puts them to sleep and the viagra stops them rolling out of bed :-)
It doesn'tjust just like that -the man has to be in the mood and thinking arousing thoughts for it to kick into action,which I was told was approx an hour after taking,and should be taken on an empty stomach(I dont know why).
sexyrussian - From my observations when travelling (extensively, on business) in your claimed fatherland: most of your compatriots clearly didn't care a f*** about the age of the prospective client; all they wanted was the hard currency. (or has it aall changed now we have the "Hard Rouble"??