If i want to transfer money from euros to pesos, and its asking me the payment currency, what does it mean? The currency from its taken or recived?
It is easily available; you can get it from energy drinks, coffee, tea, coke. It's extremely effective in increasing your energy before a workout because it is such a fast acting substance. Caffeine increases your mental alertness. However, a word of caution, caffeine only offers a temporary boost of energy.
For gaining muscle, the best advice I can give you is to eat, or drink, as much carbohydrates and protein as possible. The best way to load up on carbohydrates and protein is to eat some yogurt, and some fruit. Fruit has lots of simple sugars that give you the preferred energy source your body needs for your workout.