It is important to remember that dietary carnitine is easily
obtained from foods such as meat, particularly beef, sheep, and
lamb. However with supplemental carnitine, it does come in two
forms, L-Carnitine and D-Carnitine; only the L form is biologically
active as the body cannot use D-Carnitine, and there is some
evidence to suggest that D-Carnitine may in fact be harmful.
Bioavailability was similar for free L-Carnitine and the
L-Carnitine salt L-Carnitine L-Tartrate, while those of the ester
version of Carnitine (Acetyl L-Carnitine) was lower.
L-Carnitine L-Tartrate was also shown to be absorbed faster
than the other L carnitine compounds.
