From the Guidelines
L-carnitine works by transporting long-chain fatty acids into mitochondria for energy generation, playing a crucial role in fatty acid metabolism and energy production, particularly in high-energy demanding tissues such as skeletal muscles, myocardium, liver, and adrenal glands. This process is facilitated by the carnitine palmitoyltransferase system, which consists of three enzymes: carnitine palmitoyltransferase I (CPT I), carnitine palmitoyltransferase II (CPT II), and carnitine:acylcarnitine translocase (CACT) 1. L-carnitine is naturally produced in the body from amino acids L-lysine and L-methionine, and is also obtained from dietary sources.
The mechanism of action of L-carnitine involves its role as a carrier molecule, transporting long-chain fatty acids from the cytosol across the outer and inner membranes of the mitochondrial matrix for β-oxidation, i.e., for energy generation 1. This is essential for energy metabolism, particularly in tissues that rely heavily on fat for fuel. L-carnitine supplementation can increase the body's capacity to transport fatty acids, potentially enhancing energy production and exercise performance.
Key aspects of L-carnitine's mechanism of action include:
- Transport of long-chain fatty acids into mitochondria for energy generation
- Involvement in the carnitine palmitoyltransferase system
- Natural production in the body from amino acids L-lysine and L-methionine
- Dietary sources, including meat and dairy products
- Potential benefits for energy production, exercise performance, and addressing symptoms of certain medical conditions or deficiencies 1.
From the FDA Drug Label
CARNITOR® (levocarnitine) is a naturally occurring substance required in mammalian energy metabolism. It has been shown to facilitate long-chain fatty acid entry into cellular mitochondria, thereby delivering substrate for oxidation and subsequent energy production. Levocarnitine clears the acylCoA compound by formation of acylcarnitine, which is quickly excreted CARNITOR® (levocarnitine) is a carrier molecule in the transport of long-chain fatty acids across the inner mitochondrial membrane.
The mechanism of action of L-carnitine (Levocarnitine) is to facilitate the transport of long-chain fatty acids into cellular mitochondria, where they can be oxidized and used for energy production. It does this by forming acylcarnitine, which can then be quickly excreted, thereby clearing acylCoA compounds that can disrupt intermediary metabolism 2. L-carnitine acts as a carrier molecule in this process 2.
- Key points:
- Facilitates long-chain fatty acid entry into mitochondria
- Forms acylcarnitine to clear acylCoA compounds
- Acts as a carrier molecule in fatty acid transport
From the Research
Mechanism of Action of L-Carnitine
The mechanism of action of L-carnitine involves the transportation of fatty acids into the mitochondrial matrix, where they are broken down to produce energy 3, 4, 5. This process is essential for the production of energy from fatty acids and is critical for the functioning of cells, particularly in the heart and skeletal muscles.
Role in Fatty Acid Metabolism
L-carnitine plays a crucial role in the metabolism of fatty acids by regulating the level of acylo-CoA and CoA in the mitochondria and cytosol 6. It also provides acetyl moieties for the biosynthesis of acetocholine and carries long-chain fatty acids into mitochondria for beta-oxidation.
Cardiopathing Effects
L-carnitine has been shown to have cardiopathing effects, including reducing oxidative stress, inflammation, and necrosis of cardiac myocytes 4, 5. It also regulates calcium influx, endothelial integrity, intracellular enzyme release, and membrane phospholipid content for sustained cellular homeostasis.
Regulation of Caspase Activity
L-carnitine has been found to inhibit apoptosis induced by Fas ligation and inhibit the activity of recombinant caspases 3,7, and 8 7. However, its long-chain fatty acid derivative, palmitoylcarnitine, stimulates the activity of all caspases and reverses the inhibition mediated by carnitine.
Key Points
- L-carnitine transports fatty acids into the mitochondrial matrix for energy production
- Plays a crucial role in fatty acid metabolism and energy production
- Has cardiopathing effects, including reducing oxidative stress and inflammation
- Regulates caspase activity and inhibits apoptosis
- Can be found in various food sources, including animal by-products, milk products, and some fruits and vegetables 3, 6