Is L-Carnitine The Best Fatloss Supplement? The Benefits, Dosing, and Side Effects

The Science of L-Carnitine

Synthesized from lysine and methionine, beta-hydroxy butyrate, or carnitine, assists with fat oxidation via transportation of fatty acids from the cytosol to the mitochondria (Haff, & Triplett, 2016, p.242). The supplement is favored in it’s ability to spare muscle glycogen through increased fat utilization. Carnitine increases blood flow, detoxifies ammonia (Benardot, 2012, p.120), “reduces markers of cellular damage and free radical formation,” and assists with recovery from muscle injury (Fielding, Riede, Lugo, & Bellamine, 2018). Although research has suggested that carnitine may decrease lactic acid production (Benardot, 2012, p.120) and enhanced recovery from exercise, most studies have been unable to display elevated muscle carnitine levels after supplementation protocols (Haff, & Triplett, 2016, p.242).

Research Proven Dosing

Although there is not a set standard for carnitine dosing, studies have utilized a protocol of 2g per day for a 3 week time period. Typical dosing for carnitine is 1 to 2g per day (Benardot, 2012, p.121), as consumers should be able to tolerate 3g of carnitine per day without any adverse effects, although they should be cautious of the potential for health risks with higher dosing or prolonged usage (Haff, & Triplett, 2016, p.242). Fielding, Riede, Lugo, and Bellamine (2018) suggested that a 12-week supplementation protocol of carnitine may increase plasma and muscle carnitine, but might not affect muscle function or energy metabolism as observed in literature.

Side Effects of the Ingredient

Reports have shown that carnitine, in the form of DL-carnitine, has shown the adverse effect of muscle weakness. If carnitine supplementation is considered, one should focus on the quaternary amine in the form of l-carnitine (Benardot, 2012, p.120-121).


Benardot, D. (2012). Advanced Sports Nutrition. Human Kinetics

Haff, G., & Triplett, N. T. (2016). Essentials of strength training and conditioning. Champaign, IL: Human Kinetics.

Fielding, R., Riede, L., Lugo, J. P., & Bellamine, A. (2018). l-Carnitine Supplementation in Recovery after Exercise. Nutrients, 10(3), 349.

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