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
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.
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.