Nutritional therapy

Download as PDF


L-Carnitine plays an essential role in converting fatty acids into metabolic energy. It is the only substance capable of transporting long-chain fatty acids across the inner mitochondrial membranes in the mitochondria, where they are burned (undergo beta oxidation). This is of particular importance in organs such as, for example, the heart, which are greatly dependent on beta oxidation and fat burning for their energy supply. Conversely, L-Carnitine transports the metabolic products from the citric acid cycle out of the mitochondrion and back into the cytoplasm. In people who use a lot of energy each day, such as during intensive physical work, sport, etc., L-Carnitine increases energy production in the muscle cells and it improves the oxygen uptake. It inhibits the formation and stimulates the removal of lactic acid and has an anti-fatigue effect in the event of a lack of oxygen in the tissues, amongst others as a result of lengthy physical work. L-Carnitine is also used when there is a lack of energy and fatigue on account of illness. However, acute exertion will result in an increased breakdown of L-Carnitine. Marathon runners excrete significantly increased amounts of L-Carnitine through perspiration and urine, which can deplete their own stores and delay recovery. In untrained individuals, L-Carnitine results in a significant improvement in performance, comparable to the effects of training. Conversely, training increases the L-Carnitine levels in the muscles.

Because sperm is also largely dependent on fat burning, L-Carnitine is also of significant importance for the quality of the sperm.

L-Carnitine is also involved in the production of energy from ketone bodies, pyruvate and/or amino acids (including the branched chain amino acids). It also has a protective effect against ammonia intoxication, because it stimulates the incorporation of ammonia in urea.

Because L-Carnitine is almost exclusively present in animal products, (carnis = meat), and a vegetarian diet is also often poor in the building blocks of L-Carnitine (lysine and methionine), deficiencies can arise in pure vegetarians.

For the past fifteen years, L-Carnitine has also been added to baby formulas, which again emphases the importance and the safety of this nutrient.


  • chronic fatigue
  • weakness
  • anaerobism and lactate accumulation
  • heart conditions (weakness, rhythm disorders)
  • angina pectoris
  • hypercholesterolemia
  • hypertension
  • intermittent claudication
  • hepatic disorders
  • renal disorders
  • diabetes
  • infertility (in men)
  • obesity
  • muscular dystrophy
  • improvement in performance (including in sport)
  • pregnancy and lactation period
  • vegetarianism


At the recommended doses of L-Carnitine, no contra-indications are known. Intake during pregnancy does not result in any problems, and is in fact advisable because it contributes in various ways to the wellness of the mother and child.

Side effects

As far as is known, at the stipulated dose, L-Carnitine does not cause any adverse effects.


A number of interactions are known of medicines containing L-Carnitine. A number of well-known anti-epileptics (for example phenobarbital, phenytoin, and carbamazepine) can significantly lower the L-Carnitine levels. Other interactions with mainstream or natural medicines are also possible. Consult an expert about this.


Every day, take around 400 mg of L-Carnitine half an hour before the meal with water.

It is best not to take L-Carnitine at the same time as proteins, because the simultaneous presence of large amounts of other amino acids can impede the absorption of L-Carnitine. It is not advisable to take L-Carnitine in the evening, because the alertness and urge for activity that this can result in can potentially disturb the night’s sleep. In relation to training or important matches, it is recommended that L-Carnitine is taken approximately two hours beforehand.


In addition to supplementation of deficiencies, for stimulating the body’s own biosynthesis (particularly in the liver and kidneys) of L-Carnitine, it is advisable to also provide supplementation with the building blocks of L-Carnitine (the amino acids L-Lysine and L-Methionine), as well as with the co-factors in the synthesis (niacin, vitamin B6, vitamin C magnesium and iron). Apart from with the aforementioned nutrients, this need can best be met by a basic supplementation with a good multi and vitamin C.


  1. Arrigoni-Martelli E, Caso V. Carnitine protects mitochondria and removes toxic acyls from xenobiotics. Drugs Exp Clin Res. 2001;27(1):27-49.
  2. Atar D, Spiess M, Mandinova A et al. Carnitine--from cellular mechanisms to potential clinical applications in heart disease. Eur J Clin Invest. 1997 Dec;27(12):973-6.
  3. Bacurau RF, Navarro F, Bassit RA et al. Does exercise training interfere with the effects of L-carnitine supplementation? Nutrition. 2003 Apr;19(4):337-41.
  4. Bartlett K, Pourfarzam M. Defects of beta-oxidation including carnitine deficiency. Int Rev Neurobiol. 2002;53:469-516.
  5. Brass EP. Supplemental carnitine and exercise. Am J Clin Nutr. 2000 Aug;72(2 Suppl):618S-23S.
  6. Evangeliou A, Vlassopoulos D. Carnitine metabolism and deficit--when supplementation is necessary? Curr Pharm Biotechnol. 2003 Jun;4(3):211-9.
  7. Hoppel C. The role of carnitine in normal and altered fatty acid metabolism. Am J Kidney Dis. 2003 Apr;41(4 Suppl 4):S4-12.
  8. Kelly GS. L-Carnitine: therapeutic applications of a conditionally-essential amino acid. Altern Med Rev. 1998 Oct;3(5):345-60.
  9. Kerner J, Hoppel C. Genetic disorders of carnitine metabolism and their nutritional management. Annu Rev Nutr. 1998;18:179-206.
  10. Llansola M, Erceg S, Hernandez-Viadel M, Felipo V. Prevention of ammonia and glutamate neurotoxicity by carnitine: molecularmechanisms. Metab Brain Dis. 2002 Dec;17(4):389-97.
  11. Miller B, Ahmad S. A review of the impact of L-carnitine therapy on patient functionality in maintenance hemodialysis. Am J Kidney Dis. 2003 Apr;41(4 Suppl 4):S44-8.
  12. Muller DM, Seim H, Kiess W et al. Effects of oral L-carnitine supplementation on in vivo long-chain fatty acid oxidation in healthy adults. Metabolism. 2002 Nov;51(11):1389-91.
  13. Patrick L. Nutrients and HIV: part three - N-acetylcysteine, alpha-lipoic acid, L-glutamine, and L-carnitine. Altern Med Rev. 2000 Aug;5(4):290-305.
  14. Pauly DF, Pepine CJ. The role of carnitine in myocardial dysfunction. Am J Kidney Dis. 2003 Apr;41(4 Suppl 4):S35-43.
  15. Ramsay RR. The role of the carnitine system in peroxisomal fatty acid oxidation. Am J Med Sci. 1999 Jul;318(1):28-35.
  16. Rubin MR, Volek JS, Gomez AL. Safety measures of L-carnitine L-tartrate supplementation in healthy men. J Strength Cond Res. 2001 Nov;15(4):486-90.
  17. Tein I. Carnitine transport: pathophysiology and metabolism of known molecular defects. J Inherit Metab Dis. 2003;26(2-3):147-69.
  18. Vaz FM, Wanders RJ. Carnitine biosynthesis in mammals. Biochem J. 2002 Feb 1;361(Pt 3):417-29.