L-carnitine levels in the seminal plasma of fertile and infertile men: correlation with sperm quality

Int J Fertil Womens Med. May-Jun 2000;45(3):236-40.


Objective: To confirm the presence of L-carnitine in human seminal plasma, to show differences between L-carnitine concentrations in fertile and infertile subjects, and to show potential relationships between L-carnitine and semen quality.

Study design: Seminal plasma from 101 men obtained by masturbation was examined for the presence of L-carnitine. Semen samples were divided as follows: (a) in eight groups according to the etiology of fertility, (b) in two groups on the basis of normal or abnormal spermiogram, (c) correlation of the amount of L-carnitine in seminal plasma with values of the spermiogram.

Results: We found the following: (1) L-carnitine levels differ significantly between controls and the patient groups (P < .0001) (2) The group with normal spermiogram has a mean value for L-carnitine of 478.4 while the abnormal one comes to 100.58. This difference is statistically significant (P < .0001). (3) There is a statistically significant, positive correlation between L-carnitine and the number of spermatozoa, the percentage of motile spermatozoa, and the percentage of normal forms (P < .0001).

Conclusion: These findings suggest that determination of seminal carnitine values might provide the physician with an additional means of evaluating the infertile male.

MeSH terms

  • Adult
  • Carnitine / analysis*
  • Humans
  • Infertility, Male / diagnosis*
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Semen / chemistry*
  • Semen / cytology
  • Sperm Motility
  • Spermatozoa / cytology
  • Spermatozoa / physiology*


  • Carnitine