Title: Carnitine
CAS Registry Number: 541-15-1
CAS Name: (2R)-3-Carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium inner salt
Additional Names: L-(3-carboxy-2-hydroxypropyl)trimethylammonium hydroxide inner salt; (-)-b-hydroxy-g-trimethylaminobutyric acid; L-carnitine; levocarnitine; vitamin BT
Trademarks: Cardiogen (UCB); Carnicor (Sigma-Tau); Carnitor (Sigma-Tau); L-Carn (Sigma-Tau); Lefcar (GSK); Levocarnil (Sigma-Tau); Miocor (Ecobi); Miotonal (Caber); Nefrocarnit (Medice)
Molecular Formula: C7H15NO3
Molecular Weight: 161.20
Percent Composition: C 52.16%, H 9.38%, N 8.69%, O 29.78%
Literature References: Essential cofactor of fatty acid metabolism; required for the transport of fatty acids through the inner mitochondrial membrane. Synthesized primarily in the liver and kidney; highest concentrations found in heart and skeletal muscle. Named derived from the Latin word, carnis, meaning meat or flesh. Dietary sources include red meat, dairy products, beans, avocado. Isoln from meat extract: W. Gulewitsch, R. Krimberg, Z. Physiol. Chem. 45, 326 (1905); H. E. Carter, P. K. Bhattacharyya, Methods Enzymol. III, 660 (1957). Identification as vitamin BT: H. E. Carter et al., Arch. Biochem. Biophys. 38, 405 (1952). Synthesis: M. Tomita, Y. Sendju, Z. Physiol. Chem. 169, 263 (1927); R. Voeffray et al., Helv. Chim. Acta 70, 2058 (1987). Enantioselective synthesis from glycerol: M. Marzi et al., J. Org. Chem. 65, 6766 (2000). Biosynthesis: G. Wolf, C. R. A. Berger, Arch. Biochem. Biophys. 92, 360 (1961). Absolute configuration: T. Kaneko, R. Yoshida, Bull. Chem. Soc. Jpn. 35, 1153 (1962). Metabolism in humans: M. E. Mitchell, Am. J. Clin. Nutr. 31, 293 (1978). Historical review: G. Fraenkel, S. Friedman, Vitam. Horm. XV, 73-118 (1957). Review of physiological significance and deficiency syndromes: C. J. Rebouche, D. J. Paulson, Annu. Rev. Nutr. 6, 41-66 (1986); of clinical pharmacology: J. J. Bahl, R. Bressler, Annu. Rev. Pharmacol. Toxicol. 27, 257-277 (1987); of biosynthesis in mammals: F. M. Vaz, R. J. A. Wanders, Biochem. J. 361, 417-429 (2002). Review of effect on myocardial metabolism and clinical experience in ischemic heart disease: R. Lango et al., Cardiovasc. Res. 51, 21-29 (2001); of use as dietary supplement in athletes: H. Karlic, A. Lohninger, Nutrition 20, 709-715 (2004). Symposium on physiology, pharmacology and therapeutic potential: Ann. N.Y. Acad. Sci. 1033, 1-197 (2004).
Properties: Crystals from anhydrous ethanol + acetone, dec 196-198° (Carter, Bhattacharyya); also reported as crystals from isopropanol, mp 200° (dec) (Marzi). Very hygroscopic solid. [a]D25 -31.3° (c = 10 in water); [a]54625 -37.0° (c = 10 in water). Sol in water, hot alcohol. Practically insol in acetone, ether, benzene.
Melting point: mp 200° (dec) (Marzi)
Optical Rotation: [a]D25 -31.3° (c = 10 in water); [a]54625 -37.0° (c = 10 in water)
Derivative Type: Hydrochloride
CAS Registry Number: 6645-46-1
Additional Names: Levocarnitine chloride
Trademarks: Flatistine (Sanofi-Aventis)
Molecular Formula: C7H15NO3.HCl
Molecular Weight: 197.66
Percent Composition: C 42.54%, H 8.16%, N 7.09%, O 24.28%, Cl 17.94%
Properties: Crystals, dec 142°.
Derivative Type: DL-Form
CAS Registry Number: 406-76-8
Additional Names: g-Amino-b-hydroxybutyric acid trimethylbetaine; g-trimethyl-b-hydroxybutyrobetaine
Literature References: Synthesis: E. Strack et al., Ber. 86, 525 (1953); H. E. Carter, P. K. Bhattacharyya, J. Am. Chem. Soc. 75, 2503 (1953).
Properties: Hygroscopic crystalline solid, dec 195-197°. Sol in water, ethanol.
Derivative Type: DL-Form hydrochloride
CAS Registry Number: 461-05-2
Properties: Needles from ethanol, mp 196° (dec). Very sol in water; sol in hot ethanol; slightly sol in cold ethanol. Practically insol in acetone, ether.
Melting point: mp 196° (dec)
Derivative Type: D-Form
CAS Registry Number: 541-14-0
Literature References: Prepn: S. Friedman et al., Arch. Biochem. Biophys. 66, 10 (1957).
Properties: Crystals, dec 210-212°. [a]D +30.9°. Very sol in water and alcohol. Practically insol in acetone and ether.
Optical Rotation: [a]D +30.9°
Derivative Type: D-Form hydrochloride
CAS Registry Number: 10017-44-4
Properties: Crystals, dec 142°.
Therap-Cat: Vitamin (enzyme cofactor).
Keywords: Enzyme Cofactor; Vitamin/Vitamin Source.
Carotol Caroverine Caroxazone Carpaine Carpetimycins

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Systematic (IUPAC) name
Clinical data
AHFS/ Micromedex Detailed Consumer Information
Legal status  ?
Routes oral and iv
Pharmacokinetic data
Bioavailability < 10%
Protein binding None
Metabolism slightly
Excretion Urine (> 95%)
CAS number 541-15-1 YesY
ATC code A16AA01 (L form)
PubChem CID 288
DrugBank DB00583
ChemSpider 282 YesY
KEGG C00318 YesY
ChEBI CHEBI:17126 YesY
Chemical data
Formula C7H15NO3 
Mol. mass 161.199 g/mol
 N (what is this?)  (verify)

Carnitine is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine.[1]

In living cells, it is required for the transport of fatty acids from the intermembraneous space in the mitochondria, into the mitochondrial matrix during the breakdown of lipids (fats) for the generation of metabolic energy.[2] It is widely available as a nutritional supplement. Carnitine was originally found as a growth factor for mealworms and labeled vitamin BT,[3] although carnitine is not a proper vitamin.[4] Carnitine exists in two stereoisomers: Its biologically active form is L-carnitine, whereas its enantiomer, D-carnitine, is biologically inactive.[2][5]