4g L-Carnitine Per Day do not Increase Muscle Carnitine and/or Exercise Performance

Only 2 days ago, you read at the SuppVersity about L-Carnitine being a costly, but ineffective ingredient in many weight loss supplements. Today's news is about a study on the effect of 14-day l-carnitine supplementation (4g/day) on muscle and blood carnitine fractions, and muscle and blood lactate concentrations, during high-intensity sprint cycling exercise. The results observed in 8 subjects were unambiguous:

L-carnitine supplementation had no significant effect on muscle carnitine content and thus could not alter lactate accumulation during exercise.

The increase of plasma carnitine, on the other hand, is insufficient to bring about the ergogenic effects carnitine supplements are advertised for. So if you can't get it into the cell, you could as well dump it into the toilette - or better just don't buy it ;-)