Galloway, S. D., & Abramowicz, W. N. (2002). Effects of acute and chronic L-Carnitine administration on substrate metabolism in endurance athletes. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 1293.

The effects of L-Carnitine (LC) supplementation duration on substrate metabolism during steady-state cycling were observed. Well-trained endurance cyclists (N = 6) attended a laboratory on three occasions, two weeks apart, three hours after ingesting a standardized pre-exercise meal. Ss were given a chronic dose (3 gm/day for two weeks), an acute dose (3 gm glucose for 13 days and 3 gm LC three hours before exercise), and placebo (3 gm glucose for two weeks). Exercise was 60 minutes of cycling at 60% VO2max.

Only chronic supplementation produced a significant effect of higher CHO oxidation over the 60-min exercise.

Implication. L-Carnitine has little effect on substrate metabolism factors in trained endurance athletes.

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