L-carnitine is a calcium chelator: a reason for its useful and toxic effects in biological systems

J Basic Clin Physiol Pharmacol. 2015 Mar;26(2):141-5. doi: 10.1515/jbcpp-2014-0016.


Background: Investigation of the direct link between l-carnitine (LC), a quaternary ammonium compound that facilitates the passage of unsaturated fatty acids into the mitochondrial matrix, and free calcium (Ca2+) is needed to explain a number of varying results obtained from different in vitro and in vivo studies of LC as a supplement.

Methods: The chemical structure of LC, which contains oxygen ligand atoms, prompted to measure its activity asa Ca2+ chelator. The measurement was carried out spectrophotometri cally by measuring the reduction in the formation of Ca2+-o-cresolphthalein complexone (Ca-CPC) in the presence of different doses of LC (0.075, 0.75, and 7.5 mM) compared to the control (0.0 mM LC).

Results: The effect of LC was measured as a free entity in solution and when added to human serum. Our results showed a significant decrease (p < 0.05) in the average absorbance of Ca-CPC in the presence of LC compared to the control.

Conclusions: In conclusion, LC exhibits a significant Ca2+ chelating activity. As Ca2+ is vital in the biochemical and physiological processes of living cells, LC could be affecting the calcium-dependent biological systems by limiting the levels of free Ca2+. Examples include decelerating the blood clotting process, amplifying the effect of anticoagulants, reducing nitric oxide synthase activity, inhibiting

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism*
  • Calcium Chelating Agents / administration & dosage
  • Calcium Chelating Agents / chemistry
  • Calcium Chelating Agents / pharmacology*
  • Carnitine / administration & dosage
  • Carnitine / chemistry
  • Carnitine / pharmacology*
  • Dietary Supplements
  • Dose-Response Relationship, Drug
  • Humans
  • Phenolphthaleins / metabolism


  • Calcium Chelating Agents
  • Phenolphthaleins
  • 2-cresolphthalexon
  • Carnitine
  • Calcium