In our cells various mechanisms exist that provide energy. Insights of the last years reveal that the influence of one particular energy production mechanism has an effect on the functioning of the entire cell.

The most potent mechanisms are focused on the mitochondria, the powerhouses of the cell. The amino acid carnitine is a substance that has a direct impact as a facilitator of energy in mitochondria. There are different forms of carnitine, however, each with their unique characteristics and effects. On the market are acetyl L-carnitine, L-carnitine fumarate, propionyl-L-carnitine and L-carnitine tartrate, either in the form of capsules or tablets. Below we briefly discuss the most common L-carnitine variants.

L-Carnitine as a bodily substance

L-Carnitine is considered the foundational shape for all of the various forms. L-Carnitine is a natural substance involved in energy metabolism. The body can make this molecule from the amino acids lysine and methionine. Through food, we ingest L-carnitine on a daily basis.

As biologically active compound, L-carnitine plays an essential role in the metabolizing of fatty acids to produce energy. It is the only substance that can bring long-chain fatty acids deep into the mitochondria where they are burnt (beta-oxidation). Athletes, bodybuilders and people with increased energy needs use this amino acid in high amounts. Because L-carnitine is found almost exclusively in animal products, vegetarians or vegans may also benefit from additional supplementation.

D-Carnitine may antagonize L-carnitine

D-Carnitine is the stereoisomer of L-carnitine but this form you will not regularly find in food supplements. D-Carnitine is biologically active and can counteract L-carnitine and thus even cause a shortage of the latter.

Acetyl-L-Carnitine, the neurological variant

Acetyl-L-carnitine (ALCAR) is L-carnitine bound to an acetyl group. This form of carnitine is known as the neurological variant of L-carnitine because it can pass through the blood-brain barrier. As a result, it has more interactions with the central nervous system. These unique properties cannot be attributed to other forms of carnitine.

The acetyl group not only ensures that acetyl-L-carnitine is active in the brains and nerves. It is also an important substrate in the production of the neurotransmitter acetylcholine, and of acetyl-coenzyme A. This is the most important intermediate in the production of energy from amino acids, fatty acids and sugars. Are you looking for a supplement benefitting body and mind, this variant may be the most eligible.

Propionyl-l-carnitine and nitrogen

Propionyl-L-carnitine (PLC), or Glycine propionyl-L-carnitine (GPLC), is bound to the amino acid glycine and esterified with a short-chain fatty acid. In the mitochondria it is converted to L-carnitine and propionyl coenzyme A. This combination results in intermediate molecules that are used in energy production (citric acid cycle). This is a synergistic effect.

Propionyl L-carnitine is specifically active in the area of blood flow and its regulation than are other forms of carnitine because it affects the production of nitrogen. Propionyl-L-carnitine also has a high degree of interaction with testosterone.

In time-critical situations, there's L-Carnitine L-tartrate

L-carnitine L-tartrate (LCLT) is L-carnitine bound to tartaric acid, and is absorbed faster than other L-carnitine variants. The rapid influx makes this form particularly suitable for time-critical situations, such as right before or right after sporting activities, such that the supplement is mainly used by athletes. Also, L-carnitine L-tartrate interacts with hormones such as testosterone, for example, as it modulates the availability of the androgen receptor.

L-Carnitine Fumarate for weight loss

L-carnitine Fumarate is bound to fumaric acid. This patented shape has been put on the market under the brand name Carnishield ™ as a carnitine for the cardiovascular system.

L-Fumarate is a substance that occurs naturally in the body as an citric acid cycle intermediate; in this cycle energy (ATP) is produced. Just as vitamin D3, fumaric acid is produced in the skin when exposed to direct sunlight. Fumaric acid coupled to the L-carnitine part creates a synergistic whole. This form is widely used as an energy booster and to assist with weight loss.

How much do I need?

Depending on the form that you take, dosage may vary. For L-carnitine this may be 1-4 grams per day, while for Acetyl-L-carnitine, it would be 1-3 grams per day. Before usage, always read the label instructions and honor the dosage indicated on the label. Doctors, therapists and other health professionals may prescribe a different dose. If you are taking medication, always consult with your doctor before you start with L-carnitine supplements.