Taurine

Taurine is an organic compound. It is up to 0.1% of total human body weight, and is a main constituent of bile. Taurine is essential for the heart, the skeletal muscles, the retina, and the nerves. The body makes it from the amino acid cysteine.
Taurine comes from the Latin /taurus/ which means bull or ox. It was first extracted from ox bile in 1827.
Food.
Taurine is in fish and meat. The daily intake is around 58 mg (range from 9 to 400 mg). It is low or negligible from a strict vegan diet. Taurine intake is generally less than 200 mg/day.
Energy drinks.
Synthetic taurine is used to make some "energy drinks". Many contain 1000 mg per serving, and some as much as 2000 mg.