Absorption and excretion of L-carnitine during single or multiple dosings in humans
Baker, H.; Frank, O.; DeAngelis, B.; Baker, E.R.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 63(1): 22-26
1993
ISSN/ISBN: 0300-9831 PMID: 8320054 Document Number: 418791
Changes of short-chain (free) and long-chain (acyl) carnitine activity (CA) in plasma, whole blood, red blood cells (cbc) and urine and induced (a) by ingestion of L-carnitine as a single dose of 500 mg, or 2500 mg, or (b) by ingestion of a daily dose of 2500 mg for 10 days. A single 500-mg dose induced insignificant increases of CA in blood constituents. However elevated free CA was noted in urine. Single or daily high doses - e.g. 2500 mg of carnitine - significantly increased free and acyl-CA in plasma, whole blood and urine, but these increases were low. Variations in dosage or frequency of carnitine intake led to no changes in rbc CA; presumably CA in plasma diffused only slowly into rbc. The apparent low absorption of carnitine suggests that oral therapy may not effect rapid repletion of body stores of CA.