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Study Shows Popular Erectile Dysfunction Drug May Lower Male Fertility

Study Shows Popular Erectile Dysfunction Drug May Lower Male Fertility

Could Viagra be detrimental for male fertility?Men, if you knew Viagra® could have negative impacts on your fertility, would you still consider using it? According to a 2007 study men who take Viagra® may be lowering their fertility. The conclusion of the study published in the journal Fertility & Sterility, was that taking sildenafil citrate, well known under the name Viagra®, may significantly increase sperm motility but negatively affect sperm acrosome reaction.

The purpose of this study was to determine the side effects of sildenafil citrate on sperm function given this drugs’ popular marketing for erectile dysfunction in reproductive-age men with fertility health issues leading to erectile dysfunction. These fertility health issues range from psychological issues, diabetes, hormone imbalances, low libido, being overweight, to abnormalities of the genitalia (physical or genetic).

Study Particulars:

Fifty-seven males, ranging in age from 26 to 42 years old, undergoing examinations for infertility at the Andrology Laboratory, Royal Maternity Hospital, Belfast, due to sperm health concerns, participated in the study by giving semen samples.

Semen analysis showed that participants already had reduced sperm motility upon entering the study. Sperm samples were divided into two groups – the first having the best fertilization potential and the second showing poorer potential in terms of being able to fertilize an egg – sperm motility was analyzed in a laboratory setting after exposure to sildenafil citrate for up to 180 minutes.

Study Results:

The speed and number of sperm able to successfully swim forward was significantly increased after being exposed to Viagra® for between 15 and 135 minutes in both groups of sperm samples. However, in both groups, Viagra® also caused a significant increase in the number of acrosome-reacted sperm – 22.1% in the first group and 16.6% in the second group.

What is the acrosome and acrosome reaction?

The acrosome is a specialized layer of cells surrounding the outer layer of the sperm head that contain enzymes necessary for sperm to penetrate a woman’s ova (egg). During the acrosomal reaction, the contents of the acrosome is released and pushed from the sperm head. The enzymes then assist the sperm in fusing to and penetrating the egg. If sperm are prematurely acrosome reacted, as was shown in this study, they become unable to fertilize the egg.

Additional Findings:

Researchers also cite several studies conducted to evaluate the effects of drugs with similar actions as Viagra®, like pentoxifylline or Trental.

These studies conclude…

  • Sperm treated with these drugs are affected by them well after sperm are washed free of the drugs, implicating irreversible effects.
  • This class of drugs inhibit reactive oxygen species (ROS) which are instrumental at lower levels in a variety of the body’s normal cellular function and survival mechanisms. At low concentrations, ROS are necessary for normal sperm function and embryo development before and after implantation. “Cell numbers of blastocysts and development of the early embryo are both significantly reduced after exposure to pentoxifylline… also observed [was] embryonic arrest and retarded development…” Should implantation occur, miscarriage is very likely to result.

Researchers concerns:

Of great concern to the study’s authors is the prescription of Viagra® to men, visiting U.K. Human Fertilization and Embryology Authority’s licensed assisted conception units, finding it difficult to produce sperm samples on demand and in timed cycles of treatment.

“In a case report of Viagra use for human-assisted reproduction the investigators noted that there was no fertilization of the oocytes despite the intracytoplasmic injection of the sperm (34). They attributed the failed fertilization to the delay in obtaining the semen sample and the resultant advanced age of the oocytes. However, it is possible that Viagra had a deleterious effect on sperm function and it was the reason for the fertilization failure. When Viagra is given to patients by oral administration there is no opportunity to remove either the sperm or the embryos from its potentially persistent and damaging effects.”

As of 2007, more than 1 billion doses of Viagra® have been prescribed to more than 23 million men worldwide, including men of reproductive age, as a sexual enhancer and for erectile dysfunction.


If you are a male experiencing fertility health issues leading to infertility, especially erectile dysfunction, and are offered Viagra® by your healthcare provider, consider talking to him/her about this study.

No matter how well or quickly an erection is obtained, how long it is maintained, or how quickly sperm can swim to fertilize an egg, if the biological process that allows a sperm to adhere to and penetrate an egg happens before the sperm meets the egg, fertilization will not be able to occur. Why take a drug that has been proven to cause this to happen? Not to mention a drug that may have lasting effects.

Erectile dysfunction and low libido may be a sign of psycho-emotional dysfunction, physical dysfunction or sometimes hormone imbalance. These conditions can also be a result of hypertension, chronic use of medications, or drug addiction. It is most beneficial to overall health, including fertility health, to address the underlying cause of any fertility health issues experienced.

Poor diet and lifestyle choices are the most common reasons for poor sperm health. Thankfully guys, you CAN make healthy diet and lifestyle choices to support erectile function, a healthy libido, hormone balance, and sperm health.

Take time to read through these great resources to help you make informed, healthy choices…
The Male Fertility Diet
Male Fertility Cleanse
Increasing Low Sperm Count and Improving Male Fertility…
Yohimbe Shown to Improve Impotence & Libido in Men
Fo-ti: Herb for Fertility Longevity


Dr. Christine Traxler M.D., OB/GYN
Dr. Christine Traxler M.D., OB/GYN

Dr. Traxler is a University-trained obstetrician/gynecologist, working with patients in Minnesota for over 20 years. She is a professional medical writer; having authored multiple books on pregnancy and childbirth; textbooks and coursework for medical students and other healthcare providers; and has written over 1000 articles on medical, health, and wellness topics.  Dr. Traxler attended the University of Minnesota College of Biological Sciences and University of Minnesota Medical School,  earning a degree in biochemistry with summa cum laude honors in 1981,  and receiving her Medical Doctorate degree (MD) in 1986.

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