L-carnitine has been used as a nutritional supplement for more than two decades.¹ It’s a trimthylated amino acid found primarily in animal proteins, with red meat regarded as the richest source, although humans are also capable of synthesizing L-carnitine from dietary amino acids. Its main function in the body is to aid in the metabolism of food into energy, but it also has been shown to be a valuable supplement for athletes by assisting the recovery process through the improvement of muscle tissue repair and reduction of muscle tissue damage.^2,3,4 What’s more, one study on healthy trained men showed that L-carnitine supplementation can significantly increase testosterone receptor concentration.⁵

Improves Recovery

Studies have shown that L-carnitine is a powerful ingredient that can help aid the post-workout recovery process. It acts as an antioxidant that can reduce free-radical formation, minimize muscle tissue disruption and promote recovery.^2,3,4 L-carnitine has even been shown to reduce muscle soreness after a workout.⁴ In the long run, proper recuperation is important for overall growth and development.

Testosterone Receptor Booster

Another important effect of L-carnitine is its ability to significantly increase testosterone receptor concentration. In fact, in one study, L-carnitine was shown to significantly increase testosterone (androgen) receptor concentration after only 21 days of supplementation in resistance-trained men.⁵ The increase in receptor availability is believed to lead to greater potential of free-testosterone utilization at the muscle fiber level. Free testosterone is the most usable form of testosterone available for pure, unadulterated growth and development of muscle.

References:

¹ Kelly, G., 1998. Alternative Medicine Review. 3(5):345-360.
² Kraemer et al., 2003. Journal of Strength & Conditioning Research. 17(3):455-462.
³ Volek et al., 2002. American Journal of Physiology – Endocrinology and Metabolism. 282:E474-E482.
⁴ Ho et al., 2010. Metabolism. 59:1190-1199.
⁵ Kraemer et al., 2006. Medicine & Science in Sport & Exercise. 38(7):1288-1296.
⁶ Swart et al., 1997. Nutrition Research. 17(3):405-414.
⁷ Wall et al., 2011. Journal of Physiology. 589(4):963-73.