Viagra takes 30 to 60 minutes to become fully active in the body and start producing a noticeable effect on your ability to develop and maintain an erection.

The amount of time required for it to start taking action depends on a variety of factors, from your diet to your personal metabolism. Also study the possible Red Bull and Viagra effects that may affect the result.

If you take your ED medication too soon before sex, it might not become active quickly enough and you could be left with an awkward situation where the drug isn’t quite fully active when you need it most.

Simply put, it's always best to be prepared. If you expect to have sex, make sure you take your recommended dose of Viagra ahead of time. This not only ensures it will be active and effective—it can also act as a useful confidence boost.

However, be sure not to take your Viagra tablet more than three or four hours before you plan to have sex because the effects of Viagra can also wear off.

Viagra generally works for about four hours and then begins to wear off. If you take a Viagra pill in the morning for your evening date, you may be out of luck. Hit that sweet spot of 30-60 minutes before sex for the best results.