Sperm quality in men is improved by supplementation with a combination of L-arginine, L-citrullin, roburins and Pycnogenol®

Minerva Urol Nefrol. 2014 Dec;66(4):217-23.


Aim: The aim of this study was to investigate the influence of Prelox®R, a combination of French maritime pine bark extract (Pycnogenol®), L-arginine, L-citrulline and roburins, on male fertility.

Methods: Sperm quality of 50 subfertile men was tested in monthly intervals in a double-blind, randomized, placebo controlled, crossover study. Patients received 2 tablets Prelox®R or placebo twice daily during test periods. Following a run-in period of 1 month, patients received either Prelox®R or a placebo for 1 month. After a wash-out period of 1 month, patients received Prelox®R or a placebo in a crossover manner for 1 month. Sperm volume, concentration of spermatozoa, total count, motility, vitality and morphology were measured by standard methods of calculation of the Fertility Index (FI) in monthly intervals. Activity of e-NOS in sperm was evaluated in parallel by measuring the quantity of L-citulline produced from L-arginine.

Results: Supplementation with Prelox®R enhanced sperm volume and concentration, motility, vitality and morphology significantly versus placebo. The Fertility Index rose to normal values during treatment with Prelox®R. e-NOS activity in sperm was elevated by Prelox®R. No adverse effects were reported.

Conclusion: Prelox®R offers a safe method to improve quality of human spermatozoa in subfertile men.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arginine / therapeutic use*
  • Aspartic Acid / therapeutic use*
  • Citrulline / therapeutic use
  • Cross-Over Studies
  • Dietary Supplements
  • Double-Blind Method
  • Drug Combinations
  • Flavonoids / therapeutic use
  • Humans
  • Infertility, Male / drug therapy*
  • Male
  • Middle Aged
  • Phytotherapy
  • Plant Extracts / therapeutic use*
  • Quercus
  • Semen Analysis*


  • Drug Combinations
  • Flavonoids
  • Plant Extracts
  • prelox
  • Citrulline
  • Aspartic Acid
  • pycnogenols
  • Arginine