What is L-Carnitine and what distinguishes this from Carnitine without the L?

L-Carnitine is an amino acid derivative that is indispensable for good health. It is involved in the metabolism of fat and its utilisation for energy. The designation "L" indicates the shape and rotational structure of many nutrients. The "L" form is the active and effective form, whereas "d" or "d-L" forms are not.

 

Supplemental carnitine can only be synthesised in the L, d or d-L forms, or as a combination with other 'carrier' molecules such as 'tartrate'. The nutritionally preferred form is L-Carnitine.