L-carnitine is an amino acid derivative that is essential to human life.
Its primary function is to transport fatty acids from the fluid of the cells into the mitochondria, where they are used to produce energy in the form of ATP via a process known as beta oxidation. The heart and endothelium which line the arteries depend largely on fats for fuel as do skeletal muscles when shifting into endurance mode. About 60%-70% of the energy used by the heart comes from the breakdown of fatty acids.
L-carnitine is also used to remove toxic by-products formed during the energy-producing process. L-carnitine is conditionally essential, i.e. the body can manufacture L-carnitine from the amino acids lysine and methionine. However, if the body cannot keep up with its own demand, it must be supplemented through the diet. L-carnitine has been found in research to support several aspects of sports performance.
Healthy men aged 19–25 received 1000mg or 2000mg of L-carnitine vs placebo per day for 3 weeks and then performed a bout of resistance exercise. Both doses of L-carnitine reduced perceived muscle pain after exercise, as well as other markers normally elevated following exercise that are involved in free radical generation.
In one study that used a combination of 2000mg L-carnitine alongside 80g carbohydrate twice a day versus 80g carbohydrate for 24 weeks, healthy males performed various endurance exercise tests on three dierent occasions. Various improvements were noted and the L-carnitine group utilised 55% less muscle glycogen compared to the control, and muscle lactate content was 44% lower. These changes were associated with an improvement in endurance performance. This is groundbreaking for all you endurance athletes out there. Just imagine how longer and faster you could go if you use less muscle energy!!
Improved running speed and decreased average oxygen consumption and heart rate following prolonged L-carnitine supplementation have also been noted in research, and a small study on L-carnitine’s eect on high repetition squat exercise found significant benefit from 2000mg L-carnitine a day versus placebo on parameters of muscle recovery.
So dosage appears to be key when using L-Carnitine, potentially giving you an edge in the following areas.
For exercise performance
To support energy production from fat
To support exercise recovery
May support optimal body composition