L-Carnitine is naturally found in the body. Endogenous carnitines exist as L-carnitine, acetyl-L-carnitine, propionyl-L-carnitine, and several other acyl-carnitine esters.
Intracellular enzymes and cell membrane transporters can rapidly interconvert the carnitines to the needed form and transport them between the tissues and extracellular space. The body can synthesize carnitines from the amino acids, lysine and methionine. The kidney aids in keeping carnitine levels stable.
Most L-carnitine in the body is found in cardiac and skeletal muscle. The highest concentration of L-carnitine is in the epididymal fluid.
L-carnitine plays a key role in cellular energy production. It is essential for beta-oxidation of long-chain fatty acids in the mitochondria.
Orally, L-carnitine is used for treating L-carnitine deficiency, for myopathies associated with medications, myocarditis associated with diphtheria, male infertility, Rett Syndrome, chronic stable angina pectoris, congestive heart failure (CHF), and myocardial infarction.
It is also used orally as a supplement in low birthweight, in strict vegetarians or vegans, and in dieters. L-carnitine is also used for anorexia, chronic fatigue syndrome, diabetes, hyperlipidemia, hyperthyroidism, attention deficit-hyperactivity disorder (ADHD), peripheral vascular disease and intermittent claudication, leg ulcers, Lyme disease, and to enhance athletic performance and endurance.
Published Clinical Studies
Levocarnitine administration in elderly subjects with rapid muscle fatigue: effect on body composition, lipid profile and fatigue.
Pistone G, Marino A, Leotta C, Dell'Arte S, Finocchiaro G, Malaguarnera M.
Department of Senescence, Urological and Neurological Sciences, University of Catania, Catania, Italy.
AIM: Levocarnitine is an important contributor to cellular energy metabolism. This study aims to evaluate the effects of levocarnitine supplementation on body composition, lipid profile and fatigue in elderly subjects with rapid muscle fatigue. METHOD: This was a placebo-controlled, randomised, double-blind, two-phase study. Eighty-four elderly subjects with onset of fatigue following slight physical activity were recruited to the study. Prior to randomisation all patients entered a 2-week normalisation phase where they were given an 'ad libitum'diet, according to the National Cholesterol Education Program (Step 2). Subjects were asked to record their daily food intake every 2 days. Before the 30-day treatment phase, subjects were randomly assigned to two groups (matched for male/female ratio, age and body mass index). One group received levocarnitine 2g twice daily (n = 42) and the other placebo (n = 42). Efficacy measures included changes in total fat mass, total muscle mass, serum triglyceride, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), apolipoprotein (apo)A1, and apoB levels. The Wessely and Powell scale was used to evaluate physical and mental fatigue. Subjects were assessed at the beginning and end of the study period. RESULTS: At the end of the study, compared with placebo, the levocarnitine-treated patients showed significant improvements in the following parameters: total fat mass (-3.1 vs -0.5 kg), total muscle mass (+2.1 vs +0.2 kg), total cholesterol (-1.2 vs +0.1 mmol/L), LDL-C (-1.1 vs -0.2 mmol/L), HDL-C (+0.2 vs +0.01 mmol/L), triglycerides (-0.3 vs 0.0 mmol/L), apoA1 (-0.2 vs 0.0 g/L), and apoB (-0.3 vs -0.1 g/L). Wessely and Powell scores decreased significantly by 40% (physical fatigue) and 45% (mental fatigue) in subjects taking levocarnitine, compared with 11% and 8%, respectively, in the placebo group (p < 0.001 vs placebo for both parameters). No adverse events were reported in any treatment group. CONCLUSION: Administration of levocarnitine to healthy elderly subjects resulted in a reduction of total fat mass, an increase of total muscle mass, and appeared to exert a favourable effect on fatigue and serum lipids.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 12875611 [PubMed - indexed for MEDLINE]
L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial.
Malaguarnera M, Cammalleri L, Gargante MP, Vacante M, Colonna V, Motta M.
Department of Senescence, Urological, and Neurological Sciences, University of Catania, Catania, Italy.
BACKGROUND: Centenarians are characterized by weakness, decreasing mental health, impaired mobility, and poor endurance. L-Carnitine is an important contributor to cellular energy metabolism. OBJECTIVE: This study evaluated the efficacy of L-carnitine on physical and mental fatigue and on cognitive functions of centenarians. DESIGN: This was a placebo-controlled, randomized, double-blind, 2-phase study. Sixty-six centenarians with onset of fatigue after even slight physical activity were recruited to the study. The 2 groups received either 2 g levocarnitine once daily (n = 32) or placebo (n = 34). Efficacy measures included changes in total fat mass, total muscle mass, serum triacylglycerol, total cholesterol, HDL cholesterol, LDL cholesterol, Mini-Mental State Examination (MMSE), Activities of Daily Living, and a 6-min walking corridor test. RESULTS: At the end of the study period, the levocarnitine-treated centenarians, compared with the placebo group, showed significant improvements in the following markers: total fat mass (-1.80 compared with 0.6 kg; P < 0.01), total muscle mass (3.80 compared with 0.8 kg; P < 0.01), plasma concentrations of total carnitine (12.60 compared with -1.70 mumol; P < 0.05), plasma long-chain acylcarnitine (1.50 compared with -0.1 micromol; P < 0.001), and plasma short-chain acylcarnitine (6.0 compared with -1.50 micromol; P < 0.001). Significant differences were also found in physical fatigue (-4.10 compared with -1.10; P < 0.01), mental fatigue (-2.70 compared with 0.30; P < 0.001), fatigue severity (-23.60 compared with 1.90; P < 0.001), and MMSE (4.1 compared with 0.6; P < 0.001). CONCLUSIONS: Our study indicates that oral administration of levocarnitine produces a reduction of total fat mass, increases total muscular mass, and facilitates an increased capacity for physical and cognitive activity by reducing fatigue and improving cognitive functions.
Publication Types:
* Randomized Controlled Trial
* Research Support, Non-U.S. Gov't
PMID: 18065594 [PubMed - indexed for MEDLINE]
Levocarnitine administration in multiple sclerosis patients with immunosuppressive therapy-induced fatigue.
Lebrun C, Alchaar H, Candito M, Bourg V, Chatel M.
Department of Neurology, Hôpital Pasteur, 30 voie romaine, 06002 Nice, France.
Nutritional factors and comedications are among the postulated causes of fatigue, a highly prevalent symptom in the multiple sclerosis (MS) population, with serious impact on patients' quality of life. Deficiency of carnitine may play a role by reducing energy production through fatty acid oxidation and numerous MS therapies can induce fatigue syndrome. The aim of this prospective open-labelled study was to collect and study serum carnitine levels in MS patients with and without disease-modifying treatment-induced fatigue syndrome. We investigated whether restoration of the carnitine pool might improve treatment-induced fatigue in MS patients. In our study, there was no statistical difference in fatigue frequency between treated and untreated patients (P=0.5). Matched to age, gender and treatments, carnitine levels were lower for MS treated patients compared to untreated MS patients (P <0.05) or controls (P <0.001). Consecutive patients with low plasma carnitine levels who experienced fatigue were substituted. Treatment consisted of oral levocarnitine, 3-6 g daily. All patients achieved normal plasma carnitine levels. For 63% of patients treated with immunosuppressive or immunomodulatory therapies, oral levocarnitine adjunction decreased fatigue intensity, especially in patients treated with cyclophosphamide and interferon beta.
Publication Types:
* Controlled Clinical Trial
PMID: 16764345 [PubMed - indexed for MEDLINE]