The excessive use of antioxidant therapy: A possible cause of male infertility?

Andrologia. 2019 Feb;51(1):e13162. doi: 10.1111/and.13162. Epub 2018 Sep 26.


Reactive oxygen species and oxidative stress are closely associated with various pathologies such as neurodegenerative diseases, ageing and male infertility. Hence, antioxidants such as vitamin C, vitamin E, N-acetyl cysteine, L-carnitine and folic acid are regularly used in various treatment regimens to protect cells from the damage induced by free radicals. However, given their over-the-counter availability at unnaturally high concentrations and also the fact that they are commonly added to various food products, patients may run a risk of consuming excessive dosages of these compounds, which may then be toxic. The few studies that have assessed antioxidant overuse and the associated adverse effects found that large doses of dietary antioxidant supplements have varying-if any-therapeutic effects even though free radicals clearly damage cells-a phenomenon that has been termed the "antioxidant paradox." Furthermore, overuse of antioxidants such as vitamin C, vitamin E, N-acetyl cysteine may lead to reductive stress, which is reported to be as dangerous to cells as oxidative stress and can be the cause of diseases such as cancer or cardiomyopathy. Therefore, we feel that there is a need for more elaborate research to establish the clear benefits and risks involved in antioxidant therapy for male infertility.

Keywords: antioxidant paradox; male infertility; redox status; redox stress; reductive stress.

Publication types

  • Review

MeSH terms

  • Antioxidants / adverse effects*
  • Humans
  • Infertility, Male / chemically induced*
  • Infertility, Male / metabolism
  • Male
  • Oxidative Stress / drug effects*
  • Reactive Oxygen Species / metabolism


  • Antioxidants
  • Reactive Oxygen Species