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Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial


In a randomly allocated, double-blind, placebo-controlled, crossover design, 50 patients with mild to moderate erectile dysfunction (ED) were treated for 1 month with placebo or a combination of L-arginine aspartate and Pycnogenol (Prelox). Patients reported sexual function from diaries. Testosterone levels and endothelial NO synthase (e-NOS) were monitored along with routine clinical chemistry. Intake of Pycnogenol for 1 month restored erectile function to normal. Intercourse frequency doubled. e-NOS in spermatozoa and testosterone levels in blood increased significantly. Cholesterol levels and blood pressure were lowered. No unwanted effects were reported. Prelox is a promising alternative to treat mild to moderate ED.

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We thank Dr J Gerß from the Institute of Medical Informatics and Biomathematics of the University Clinics Münster, Germany, for statistical evaluation of data. This study was funded by Horphag Research Ltd, UK.

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Correspondence to P Rohdewald.

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Competing Interests

Dr Stanislavov received a grant from Horphag Research Ltd to perform this study. Dr Rohdewald is a consultant for Horphag Research Ltd and holds a patent for the method of increasing sexual wellness with a combination of proanthocyanidins and L-arginine.

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Stanislavov, R., Nikolova, V. & Rohdewald, P. Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial. Int J Impot Res 20, 173–180 (2008).

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  • erectile dysfunction
  • Prelox
  • L-arginine
  • Pycnogenol
  • endothelial nitric oxide synthase (e-NOS)

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