TLDR

Injectable L-carnitine can be administered either intramuscularly (IM) or subcutaneously (Subq) with a minimum daily dose of 400mg. The optimal maximum dose is still undetermined, but 800mg with the intake of 60 to 90 grams of simple carbs or injection of 8 to 10 IUs of fast-acting insulin is often used.

Full Article

Understanding Carnitine

Carnitine, an amine compound, is synthesized from lysine and methionine, essential amino acids, primarily within the liver, kidneys, and brain.

Role of Carnitine

The importance of Carnitine becomes evident in the process of energy production. Once fatty acids are mobilized, Carnitine transports them into the mitochondria where they undergo beta oxidation, which is essential for energy generation and requires oxygen. Carnitine is indispensable in transporting fatty acids through mitochondrial membranes for oxidation.

Carnitine and Beta Oxidation

Research indicates that elevated levels of free Carnitine can potentially augment beta oxidation. Studies have shown that during high-intensity interval training sessions, the levels of free Carnitine can reduce by up to 75%, regulating the amount of beta oxidation that occurs in the cell. Increased Carnitine administration has been correlated with an elevation in acetyl-CoA levels and a consequential increase in beta oxidation.

Bioavailability

Carnitine has low oral absorption, hence is often administered through IV infusion. Its bioavailability is less than 15% in oral form, with the human absorption limit being around 3 grams.

Carnitine and Insulin

For Carnitine to be effective, it must be transported into the cells. Insulin plays a pivotal role in increasing the activity of the enzyme responsible for the movement of Carnitine into cells, enhancing the cellular levels of Carnitine and the amount of transporter available for use. Clinical studies have aimed to establish the necessary insulin levels to achieve optimal transport, with levels of approximately 70-90 mIU/l needed.

Studies and Experiments

Studies reveal that combining Carnitine with insulin can increase cellular Carnitine concentrations, resulting in increased muscle Carnitine and glycogen, and decreased pyruvate dehydrogenase activity and muscle lactate. Another study highlighted that an intake of 2g of oral Carnitine with 80g of carbohydrates twice a day for 24 weeks was sufficient to raise Carnitine levels by 21%.

Protocol for Usage

Injectable L-carnitine is administered either IM or Subq with a daily minimum dose of 400mg. The administration must be concurrent with a state of hyperinsulinemia, achievable by consuming a minimum of 60g, ideally 90g of simple hydrates, or by injecting about 10IU of ultra-rapid insulin subcutaneously. Once cellular Carnitine levels are elevated, the amount of Carnitine taken can be decreased.

Conclusion

Carnitine plays a crucial role in transporting fatty acids for energy production. The combination of Carnitine and insulin has shown promising results in increasing cellular Carnitine concentrations, leading to enhanced energy generation and metabolism. While the optimal dosage and administration method are still being explored, current protocols involving injectable L-carnitine and insulin are proving to be effective. The administration of L-carnitine can occur at any time of the day due to its effect being attributed to an increase in the cellular amount of Carnitine.