Supplements marketed specifically for weight training benefits line the shelves of sports nutrition stores everywhere. Manufacturers claim that substances such as carnitine provide an advantage by boosting anaerobic performance, increasing muscle mass, improving fat-burning capacity and aiding in recovery. The problem is, studies to support these claims are largely lacking. Despite this, preliminary data does show promise for certain benefits. However, more data is necessary to show that carnitine benefits weight training.
When it comes to bodybuilding supplements, creatine, arginine and branched-chain amino acids are mainstays, but carnitine deserves a closer look. It plays a crucial role in energy production and is concentrated throughout your skeletal muscles and heart. It basically acts as a taxi driver, shuttling long-chain fatty acids to fuel-producing structures called mitochondria that convert the fat into energy. Eating a diet that includes red meat and other animal foods provides about 60 to 180 milligrams per day, according to the National Institute of Health's Office of Dietary Supplements.
Increases Muscle Oxygen
Taking carnitine before weight training increases the concentration of oxygen in your muscle tissues, according to a small, double-blind trial in the "Journal of the international Society of Sports Nutrition" May 2010 issue. The study involved 19 resistance-trained men who took glycine propionyl-carnitine before performing weight training exercises, such as bench presses. While increased muscle oxygen is a favorable marker of exercise performance, the researchers did not test whether it resulted in enhanced anaerobic exercise.
Reduces Exercise Stress
Carnitine reduces exercise-induced stress, according to a study in the "American Journal of Physiology Endocrinology and Metabolism" February 2002 issue. Ten resistance-trained men took 2 grams of carnitine in the form of carnitine tartrate daily for three weeks. Researchers examined levels of blood markers for exercise stress, such as uric acid, after participants performed five sets of 15 to 20 squat repetitions. Researchers found carnitine significantly reduced exercise stress markers, indicating it's effective at aiding recovery.
Clinical data has yielded promising results, but it's premature to say that carnitine benefits bodybuilders. Most of the clinical data that exists is from a small sample size and shows positive markers for exercise performance, but doesn't show whether this translates into actual performance gains or not. In addition, few forms of carnitine exist, and studies showing that one form is more beneficial than the other are lacking.