Does l-arginine really works?

Answers:

No. Its an amino acid which you can effortlessly obtain contained by sufficient amounts eating foods giant in protein such as meat and fish, etc.
If you read muscle magazines you will concentration that alot of these products have some association or are downright owned by the magazine owners. Total rip rotten! Save your money bud and ensure that you get a on the edge diet complete with proteins, vegetables and fruits and the right carbohydrates (high in fiber).
Consider reading some of the glum effects of L-arginine supplementation.
Good luck.

Me and my girlfriend are having sex 4 times avg. each day for 3 months, is this bad for our vigour?

It works by being an amino sour your body can use .as for as a body-building supplement, don't bother