Taurine

Taurine is an amino acid found in white blood cells, skeletal muscles, central nervous system as well as the heart muscles. It is also found in a lot of supplements and energy drinks and pre workout supplements.

Taurine in a pre-workout supplement or an energy drink doesnt actually stimulate you - it works with a stimulant (usually caffeine) to reduce fatigue and therefore allow you to feel more relaxed and have a better workout. Another effect of Taurine is that it is a cell volumizer, meaning your muscles draw in water (in a similar way to creatine monohydrate) which allows better protein synthesis and makes your muscles look bigger. Taurine is also used by some to improve sleep because it is an inhibitory neurotransmitter, meaning it stabilizes your heartbeat which can lead to better sleep.

Take 1-3g around 30-45mins prior to a workout (for focus), or 30mins before sleep if you are using it as a neurotransmitter.

As long as you stick to recommended limits (taurine is usually not supplemented on its own anyway) then you will be fine. If you buy taurine separately and take too much you may experience nausea.