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Carnitine is a nutrient in the body that turns fat into energy. It is found in meat, dairy, and bread. Carnitine has been used to improve heart health, ease fatigue, and promote fitness. It can be taken as a pill or powder. It can also be injected into the bloodstream by a healthcare provider.


1,000 milligrams 1 to 3 times daily.

What Research Shows

Likely Effective

May Be Effective

May Not Be Effective

Unlikely to Be Effective

  • Cancer-related fatigue—unlikely to ease fatigue D1
  • Hemodialysis—unlikely to ease symptoms or improve quality of life J1
  • Kidney disease—unlikely to lower total cholesterol N1-N2

Not Enough Data to Assess

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take carnitine in small doses for a short time. Not enough studies have been done to say whether it is safe to take for a long period. It is also not known whether it is safe to take by women who are pregnant or breastfeeding.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Acute Myocardial Infarction

A1. DiNicolantonio JJ, Lavie CJ, et al. L-carnitine in the secondary prevention of cardiovascular disease: systematic review and meta-analysis. Mayo Clin Proc. 2013 Jun;88(6):544-551.

B. Attention Deficit Hyperactivity Disorder

B1. Sarris J, Kean J, et al. Complementary medicines (herbal and nutritional products) in the treatment of Attention Deficit Hyperactivity Disorder (ADHD): a systematic review of the evidence. Complement Ther Med. 2011 Aug;19(4):216-227.

C. Brain Ischemia

C1. Fedotova AV, Mironova OP, et al. [L-carnitine treatment patients with chronic cerebral ischemia]. Zh Nevrol Psikhiatr Im S S Korsakova. 2013;113(5):48-53.

D. Cancer-Related Fatigue

D1. Marx W, Teleni L, et al. Efficacy and Effectiveness of Carnitine Supplementation for Cancer-Related Fatigue: A Systematic Literature Review and Meta-Analysis. Nutrients. 2017 Nov 7;9(11). pii: E1224.

E. E. Chronic Heart Failure

E1. Song X, Qu H, et al. Efficacy and Safety of L-Carnitine Treatment for Chronic Heart Failure: A Meta-Analysis or Randomized Controlled Trials. Biomed Res Int. 2017:6274854.

F. F. Cognitive Function

F1. Chen N, Yang M, et al. L-carnitine for cognitive enhancement in people without cognitive impairment. Cochrane Database Syst Rev. 2017 Mar 26;3:CD009374.

G. G. Depression

G1. Vernoese N, Stubbs B, et al. Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis. Psychosom Med. 2018;80(2):154-159.

H. H. Diabetes

H1. Vidal-Casariego A, Burgo-Peláez R, et al. Metabolic effects of L-carnitine on type 2 diabetes mellitus: systematic review and meta-analysis. Exp Clin Endocrinol Diabetes. 2013;121(4):234-238.

H2. Xu Y, Jiang W, et al. L-carnitine treatment of insulin resistance: A systematic review and meta-analysis. Adv Clin Exp Med. 2017 Mar-Apr;26(2):333-338.

I. Fragile X Syndrome

I1. Rueda JR, Guillén V, et al. L-acetylcarnitine for treating fragile X syndrome. Cochrane Database Syst Rev. 2015 May 19;(5):CD010012.

J. J. Hemodialysis

J1. Yang SK, Xiao L, et al. Effect of L-carnitine therapy on patients in maintenance hemodialysis: a systematic review and meta-analysis. J Nephrol. 2014 Jun;27(3):317-329.

K. K. Hepatic Encephalopathy

K1. Martí-Carvajal AJ, Gluud C, et al. Acetyl-L-carnitine for patients with hepatic encephalopathy. Cochrane Database Syst Rev. 2019;1:CD011451.

L. L. Hyperthyroidism

L1. An JH, Kim YJ, et al. L-carnitine supplementation for the management of fatigue in patients with hyperthyroidism on levothyroxine treatment: a randomized, double-blind placebo-controlled trial. Enocr J. 2016;63(10):885-895.

M. M. Intermittent Claudication

M1. Delaney CL, Spark JI, et al. A systematic review to evaluate the effectiveness of carnitine supplementation in improving walking performance among individuals with intermittent claudication. Atherosclerosis. 2013 Jul;229(1):1-9.

M1. Brass EP, Koster D, et al. A systematic review and meta-analysis of propionyl-L-carnitine effects on exercise performance in patients with claudication. Vasc Med. 2013 Feb;18(1):3-12.

N. N. Kidney Disease

N1. Huang H, Song L, et al. Influence of L-carnitine supplementation on serum lipid profile in hemodialysis patients: a systematic review and meta-analysis. Kidney Blood Press Res. 2013;38(1):31-41.

N2. Chen Y, Abbate M, et al. L-Carnitine supplementation for adults with end-stage kidney disease requiring maintenance hemodialysis: a systematic review and meta-analysis. Am J Clin Nutr. 2014;99(2):408-422.

O. O. Multiple Sclerosis

O1. Tejani AM, Wasdell M, et al. Carnitine for fatigue in multiple sclerosis. Cochrane Database Syst Rev. 2012 May 16;(5):CD007280.

P. P. Obesity

P1. Pooyandjoo M, Nouhi M, et al. The effect of (L-)carnitine on weight loss in adults: a systematic review and meta-analysis of randomized controlled trials. Obese Rev. 2016;17(10):970-976.

Q. Q. Osteoarthritis

Q. Liu X, Machado GC, et al. Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis. Br J Sports Med. 2018;52(3):167-175.

R. R. Peripheral Neuropathic Pain

R1. Li S, Li Q, at al. Acetyl-L-carnitine in the treatment of peripheral neuropathic pain: a systematic review and meta-analysis of randomized controlled trials. PLoS One. 2015;10(3):e0119479.

R2. Brami C, Bao T, et al. Natural products and complementary therapies for chemotherapy-induced peripheral neuropathy: A systematic review. Crit Rev Oncol Hematol. 2016 Feb;98:325-334.

S. S. Valproic Acid Overdose

S1. Perrott J, Murphy NG, et al. L-carnitine for acute valproic acid overdose: a systematic review of published cases. Ann Pharmacother. 2010 Jul-Aug;44(7-8):1287-1293.

Last reviewed July 2019 by EBSCO NAT Review Board Eric Hurwitz, DC