V and C ease blood flow to your genitals. I believe I've read that L works more on your mind, increasing your libido, so it may be more useful to people who lack the desire to get aroused. I got a headache the only time I used L, but I expect this would improve with more use.
Viagra is available by perscription in Canada. I believe neither Cialis nor Levitra are yet approved in Canada.
Of course all 3 can be bought over the counter in other countries e.g. Mexico. You can order generic C and, I believe, L online from a Mexican site. The product is shipped from India. I was happy with the results.
I am not uncomfortable with an Indian source as, first, anyone notice how many east asian immigrant doctors there are these days and, second, India has, I understand, some hospitals specializing in surgury for patients from the first world countries. Basically you can get a procedure done in India for a lot less than in the States.
Any doctors can feel free to clear up any of my delusions.
The flush BB mentions is present and kinda weird. It feels like the adrenalin burn you get before doing something crazy. Hmmm ... a connection.
Thanks BB for mentioning the sog situation. It explains a bunch. LOL. I accidently conducted a non scientific test this morning and preliminary results support your delayed sog comment. Now that I know the situation I can use it to advantage.