L-carnitine is an amino acid (a building block for proteins) that is naturally produced in the body.
L-carnitine supplements are used to increase L-carnitine levels in people whose natural level of L-carnitine is too low because they have a genetic disorder, are taking certain drugs (valproic acid for seizures), or because they are undergoing a medical procedure (hemodialysis for kidney disease) that uses up the body’s L-carnitine. It is also used as a replacement supplement in strict vegetarians, dieters, and low-weight or premature infants.
L-carnitine is formed in the liver and kidneys from the amino acids lysine and methionine. However, it is stored elsewhere in the body, primarily in muscle (including the heart), the brain, and even in sperm. In the diet, it mainly comes from meat and other animal products. You can get some from plant products like avocado and soybeans, but as a rule, meat is the best source—and the redder the better.
Carnitine occurs in two forms, or isomers: L-carnitine and D-carnitine. L-carnitine is the active form that plays a role in energy metabolism and production. It is produced within the body, but it can also be taken as a supplement or found in many different protein foods as well. In supplement form, it’s available as a capsule, liquid or even injectable.
WHAT DOES L-CARNTINE DO?
L-carnitine helps to transport fat, particularly long-chain fatty acids, into the mitochondria of cells. Once there, they can be oxidized—used as fuel—to generate adenosine triphosphate, or ATP. L-carnitine does this cellular work both when you exercise and rest, but research confirms that it is especially effective during intense exercise.
The transfer of fat to energy is one of the main functions of carnitine
Owing to its fat-burning capabilities and the optimization of fat metabolism, carnitine is familiarly known as a ‘fat-burner’. Fatty acids are transported into the cells, where they are burned to release energy by being transported to mitochondria, the power stations of the cells. The useful long branched chain fatty acid molecules can only pass through the inner mitochondrial membrane through esterification with carnitine. This is contrary to medium and short-chain fatty acids which can penetrate the membrane without this biocarrier.
- Increases Endurance
- Enhances Weight Loss
- Prevents Muscle Damage
- Amps Up Fat Burning
- Boosts Brain Function
- Regulates Blood Sugar
- Fatigue resistance
- Burning fat as fuel
- Decreased Muscle Soreness, Improved Recovery
- Burning fat as fuel
L-Carnitine Food Sources
Animal products are the best natural sources of L-carnitine, with foods like grass-fed beef packing in the highest amount per serving. It can also be found in small amounts in some sources like vegetables and grains. Here are the foods that contain the most L-carnitine per serving, according to the National Institutes of Health
- Beef steak, cooked, 4 ounces: 56–162 milligrams
- Ground beef, cooked, 4 ounces: 87–99 milligrams
- Whole milk, 1 cup: 8 milligrams
- Codfish, cooked, 4 ounces: 4–7 milligrams
- Chicken breast, cooked, 4 ounces: 3–5 milligrams
- Ice cream, 1/2 cup: 3 milligrams
- Cheddar cheese, 2 ounces: 2 milligrams
- Whole wheat bread, 2 slices: 0.2 milligram
- Asparagus, cooked, 1/2 cup: 0.1 milligram
L-Carnitine Supplements + Dosage
The standard L-carnitine dosage is 500–2,000 milligrams daily. Based on most current research available, a dose of up to two grams per day can be used safely and effectively with minimal side effects.
The dosage may vary by the type of L-carnitine supplement, however. Acetyl-L-carnitine, for example, can be used in doses up to 2,500 milligrams per day while the dose for L-Carnitine L-Tartrate, a form typically used to enhance athletic performance, can range all the way up to 4,000 milligrams.
WHEN SHOULD I TAKE L-CARNITINE?
One of the best times to take L-carnitine is post-workout, but you can take it with any other high-carb, high-protein meal throughout the day. If you want to stack L-carnitine with other fat-burning ingredients between meals, consider using the acetyl-L-carnitine form.