L-Carnitine 600mg/ml, 10ml

What is L-Carnitine ?

L-Carnitine is a quaternary ammonium compound derived from the amino acids lysine and methionine, biosynthesised in the liver and kidneys. Research has investigated its role in fatty acid transport across the inner mitochondrial membrane via the carnitine shuttle, as well as effects on mitochondrial bioenergetics and oxidative metabolism. Supplied as a ready-to-use 600mg/ml solution in a 10ml vial, for research use only.

L-Carnitine is not a peptide. It is a small zwitterionic metabolite, (R)-3-hydroxy-4-(trimethylazaniumyl)butanoate, formula C₇H₁₅NO₃. It is stocked beside the peptide range because it is a standard reagent in mitochondrial research.

Its established job is the carnitine shuttle, which moves long-chain fatty acids into mitochondria. That shuttle is the rate-limiting entry step for long-chain fatty-acid oxidation.

L-Carnitine Research Applications

L-Carnitine is used as a defined substrate and pathway probe in mitochondrial bioenergetics. Typical work includes carnitine palmitoyltransferase activity assays, acylcarnitine profiling by tandem mass spectrometry, and fatty-acid oxidation flux in cells or isolated mitochondria. It also serves in models of carnitine shuttle deficiency, in skeletal muscle energetics work, and as a reference standard in the acylcarnitine methods behind newborn screening for fatty-acid oxidation disorders. No claim is made about supplementation in humans.

Research Overview

L-Carnitine is a quaternary ammonium compound, (R)-3-hydroxy-4-(trimethylazaniumyl)butanoate, with a molecular weight of 161.20 g/mol. Unlike the other compounds in this catalogue it is not a peptide. It is endogenously biosynthesised in the liver and kidneys from lysine and methionine through a four-step pathway proceeding via trimethyllysine and gamma-butyrobetaine, the final hydroxylation being catalysed by gamma-butyrobetaine dioxygenase.

Its central role in metabolic research is as the obligate carrier in the carnitine shuttle, the mechanism by which long-chain fatty acids cross the inner mitochondrial membrane. Long-chain acyl-CoA cannot pass that membrane directly. Carnitine palmitoyltransferase 1, sitting on the outer mitochondrial membrane, transfers the acyl group onto carnitine to form acylcarnitine; carnitine-acylcarnitine translocase moves it across the inner membrane; carnitine palmitoyltransferase 2 regenerates acyl-CoA on the matrix side, where beta-oxidation proceeds. CPT1 is the rate-limiting step of the entire pathway and is allosterically inhibited by malonyl-CoA, which is what couples fatty acid oxidation to fatty acid synthesis.

Cellular uptake depends on OCTN2, the sodium-dependent transporter encoded by SLC22A5. Loss-of-function mutations in that gene cause primary systemic carnitine deficiency, and that genetic model is a large part of why the carnitine shuttle is as well characterised as it is. A second research literature concerns the microbial metabolism of dietary carnitine rather than carnitine itself: Koeth and colleagues (Nat Med, 2013) reported that gut microbiota convert carnitine to trimethylamine, which is oxidised hepatically to trimethylamine-N-oxide, and examined the association of that metabolite with atherosclerosis in animal models. It is noted here because it is a genuine part of the compound's research picture rather than a footnote to it.

L-Carnitine is supplied here as a ready-to-use solution at 600mg/ml in a 10ml vial. It is not a licensed medicine in the UK in this presentation and is not supplied for human consumption, veterinary use, or any therapeutic purpose.

Storage and Handling

Store the sealed vial at room temperature, protected from light. It does not need freezing or -20°C storage. Once the stopper has been pierced, keep the vial at 2-8°C. Inspect the solution before each use and discard it if it turns cloudy, discoloured or shows particulates. It has no secondary structure to lose and no thiol or thioether to oxidise.

How to handle

• Supplied as a ready-to-use 600mg/ml solution. No reconstitution or bacteriostatic water is required.
• The concentrated solution can be viscous, more so when cold. Allow a refrigerated vial to reach room temperature and draw slowly.
• Store the sealed vial at room temperature, protected from light. Once pierced, date the vial, keep it at 2-8°C, and discard the solution if it turns cloudy, discoloured or shows particulates.

To mix a peptide, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis (Koeth et al., Nat Med, 2013)

Published research on L-Carnitine is indexed on PubMed. See our full UK buyer's guide for L-Carnitine.