L-Carnitine (L-C) transports fatty acids into mitochondria for oxidation and is marketed as a weight loss supplement. In a double-blind investigation to test the weight loss efficacy of L-C, 36 moderately overweight premenopausal women were pair matched on Body Mass Index (BMI) and randomly assigned to two groups (N = 18). For 8 weeks the L-C group ingested 2 g twice daily of L-C, while the placebo (P) group ingested the same amount of lactose. All subjects walked for 30 min (60—70% maximum heart rate) 4 days/ week. Body composition, resting energy expenditure (REE) and substrate utilization were estimated before and after treatment. For the subjects who completed the study (15 P, 13 L-C), no significant changes in mean total body mass (TBM), fat mass FM, and resting lipid utilization occurred over time, nor were there any significant differences between groups for any variable. Conversely REE increased significantly for all subjects, but no between group differences existed. Five of the L-C group experienced nausea or diarrhea and consequently did not complete the study. Eight weeks of L-C ingestion and walking did not significantly alter the TBM or FM of overweight women, thereby casting doubt on the efficacy of L-C supplementation for weight loss.
Rudolph G. Villani, Jenelle Gannon, Megan Self and Peter A. Rich
Christopher Barnett, David L. Costill, Mathew D. Vukovich, Kevin J. Cole, Bret H. Goodpaster, Scott W. Trappe and William J. Fink
This study examined the effects of 14 days of L-camitine supplementation on muscle and blood camitine fractions, and muscle and blood lactate concentrations, during high-intensity sprint cycling exercise. Eight subjects performed three experimental trials: control 1 (CON I, Day 0), control I! (CON II, Day 14), and L-camitine (L-CN, Day 28). Each trial consisted of a 4-rain ride at 90%
* Michael F. Bergeron * Robert W. Kenefick * Kent E. LaGasse * Deborah Riebe * 9 1994 4 4 3 3 265 265 279 279 10.1123/ijsn.4.3.265 Effect of L-Carnitine Supplementation on Muscle and Blood Camitine Content and Lactate Accumulation during High-Intensity Sprint Cycling Christopher Barnett * David L
Pérez-Landaluce * Angeles M. Patterson * 6 2000 10 10 2 2 182 182 198 198 10.1123/ijsnem.10.2.182 L-Carnitine Supplementation Combined with Aerobic Training Does Not Promote Weight Loss in Moderately Obese Women Rudolph G. Villani * Jenelle Gannon * Megan Self * Peter A. Rich * 6 2000 10 10 2
Peter Peeling, Martyn J. Binnie, Paul S.R. Goods, Marc Sim and Louise M. Burke
oxidation, at lower exercise intensities, and to promote more efficient carbohydrate oxidation and reduced lactate accumulation at higher intensities, delaying the onset of fatigue during endurance-based activity. Research on L-carnitine supplementation has shown equivocal outcomes. Marconi et al. ( 1985