Biotin is one of a handful of B vitamins that is specifically responsible for the catalysis of glucose, fatty acids, and amino acids that are converted into energy. Its water solubility makes it a crucial cofactor for five carboxylases namely acetyl-CoA carboxylase 2, pyruvate carboxylase, acetyl-CoA carboxylase 1, methylcrotonyl-CoA carboxylase, and propionyl-CoA carboxylase. Besides that, it helps in cell signalling, histone modifications and gene regulation. In gene regulation, it acts by positively altering the factors of transcription.
Acetyl-L-carnitine is important to energy production in the body and can be found in its highest concentration in the skeleton and heart muscle. It is produced by the liver and kidneys. It is not regarded as an essential nutrient and as a result no dietary recommended intake for it has been set.
The body makes sufficient carnitine to meet the needs of most people. Premature babies do not produce enough carnitine.