Written by Peter Renner, Markus Horneber and the CAM-Cancer Consortium.
Updated January 29, 2015


Abstract and key points

  • L-carnitine is a biosynthesized compound which is also obtained from dietary sources
  • L-carnitine is essential for the transportation of fatty acids into mitochondria and maintains homeostasis in key mitochondrial lipids and proteins
  • Preliminary evidence suggests that L-carnitine might protect nervous tissue from chemotherapy-induced toxicity, improves cancer anorexia-cachexia syndrome and helps against erectile dysfunction after prostatectomy
  • There is evidence that patients with advanced cancer and cancer-related fatigue do not benefit from L-carnitine supplementation
  • Supplementation of L-carnitine is safe with only minor adverse events

Carnitine is the generic term for a compound occurring naturally in humans, most animals, plants and microorganisms. It is part of the group of compounds that includes acetyl-L-carnitine and propionyl-L-carnitine. Most of the body’s carnitine is located within skeletal muscles, where it is critical for the supply of energy by the beta-oxidation of fatty acids. It also plays an important role in the stress response by modulating inflammatory and oxidative processes.

L-carnitine is not regarded as an essential nutrient because humans obtain it through biosynthesis as well as from dietary sources. Only in certain situations (e.g. increased renal loss) can the need exceed the capacity of biosynthesis. The most common commercial production of L-carnitine involves biosynthesis using cell cultures, and it is usually sold as oral supplements. 

There is evidence from four randomized controlled trials (RCTs) indicating that L-carnitine does not reduce cancer-related fatigue in patients with advanced cancer.

There is weak evidence from one small RCT and one uncontrolled study to show that L-carnitine has a positive influence on cancer anorexia-cachexia syndrome and there is also evidence that acetyl-L-carnitine or propionyl-L-carnitine could be of help in reducing erectile dysfunction after prostatectomy.

There is also weak evidence from two uncontrolled studies that acetyl-L-carnitine is effective in the treatment of chemotherapy-induced peripheral neuropathy (CIPN). Evidence concerning the prevention of CIPN through acetyl-L-carnitine is contradictory, and findings from the most recent trial introduce a note of caution because it appears possible that acetyl-L-carnitine could even increase CIPN.

There is weak evidence that L-carnitine does not protect against anthracyclin-induced cardiotoxicity, and that it reduces cardiac side effects from interleukin-2.

The available clinical data suggest that L-carnitine is well tolerated and has been safely used in clinical trials at doses from 250mg to 6g per day for up to six months. Interactions with thyroid medications have been reported.

Citation Peter Renner, Markus Horneber, CAM-Cancer Consortium. L-Carnitine [online document]. http://ws.cam-cancer.org/The-Summaries/Dietary-approaches/L-Carnitine. January 29, 2015.


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