Cobalt PeptidesResearch Grade

Scientific Reference

L-Carnitine (Levocarnitine)

Evidence profile: Preclinical, with limited uncontrolled human reports

L-carnitine is a small quaternary ammonium compound made in the liver and kidney from the amino acids lysine and methionine. It is not a peptide, and only the L-stereoisomer is recognised by the enzymes and transporters that handle carnitine. Most carnitine in the diet comes from meat and dairy foods, and the great majority of the body's store is held in skeletal and cardiac muscle. Its biochemistry has been worked out in detail, and there is a large human research literature, including work on inherited disorders of carnitine transport. Those human studies vary widely in design and quality, and their findings are often inconsistent.

Mechanism of Action

Carnitine's best-characterised role is moving long-chain fatty acids into mitochondria. Carnitine palmitoyltransferase 1 (CPT1), on the outer mitochondrial membrane, transfers the fatty acyl group from coenzyme A to carnitine; carnitine–acylcarnitine translocase carries the acylcarnitine across the inner membrane; and CPT2 on the matrix side converts it back to acyl-CoA for beta-oxidation. CPT1 is inhibited by malonyl-CoA, a control point linking fatty acid and carbohydrate metabolism. Carnitine also accepts surplus acyl groups from coenzyme A, and the acylcarnitines formed can leave the cell, which is why blood acylcarnitine profiles are used in metabolic research and screening.

Molecular Information

  • Type: Amino acid derivative (non-peptide)
  • Molecular weight: 161.20 g/mol
  • Molecular formula: C7H15NO3
  • CAS: 541-15-1

Published Research

  • Effect of l-Carnitine Supplementation on Osteoarthritis: A Systematic Review

    Kou H et al. · Molecular nutrition & food research · 2024 · Review

    PMID 38389158 — View on PubMed

  • A Meta-Analysis of the Efficacy of L-Carnitine/L-Acetyl-Carnitine or N-Acetyl-Cysteine in Men With Idiopathic Asthenozoospermia

    Wei G et al. · American journal of men's health · 2021 · Review

    PMID 33906513 — View on PubMed

  • The Effects of L-Carnitine, Acetyl-L-Carnitine, and Propionyl-L-Carnitine on Body Mass in Type 2 Diabetes Mellitus Patients

    Wang DD et al. · Frontiers in nutrition · 2021 · Review

    PMID 34820412 — View on PubMed

  • The efficacy of L-carnitine in improving malnutrition in patients on maintenance hemodialysis: a meta-analysis

    Zhou J et al. · Bioscience reports · 2020 · Review

    PMID 32490516 — View on PubMed