Here is what the Vegan Health project had to say about it:
Taurine and Carnitine
Taurine and carnitine are non-essential amino acids found primarily in animal products. If you are eating enough protein, your body should make what you need. If you go an extended period of time without eating enough protein, or if you have a metabolic problem, you might benefit from a period of supplementation. In such cases, it is prudent to contact a health professional. There is no reason for most vegetarians or vegans to be concerned.