Viagra and Male Fertility: Does any Effect Exist?

Some men with ED also face the problem of infertility. Those who are treated with the help of Viagra may worry whether the drug can positively or adversely affect their ability to conceive a child? So, let’s take a closer look at this issue. 

What is Viagra?

Generic Viagra is a top drug for treating male ED. The branded version of the drug is produced by American pharma giant called Pfizer. It is used by millions of male persons around the world. Since the original Viagra has a high price, the generics of this drug have gained great popularity in the pharmaceutical market. Regardless the version of the drug you use (branded or generic), its main active agent is sildenafil. It belongs to the class of PDE5 inhibitors.

Read also:

– an article about PDE5 inhibitors;

– must read questions before you buy Generic Viagra online.

Effects of Viagra on the Male Body

The medication temporarily sidelines PDE5 enzyme, which is able to interfere normal blood circulation in the genital area by suppressing cGMP. When a patient is sexually stimulated and is under the action of Viagra, elevated levels of cGMP lead to better vasodilation in the male organ. As a result, the medication improves penile erection when a man needs it. 

Is Generic Viagra Safe for Male Sperm?

Generic Viagra acts only on the enzyme PDE5, expanding the blood vessels in the male organ. Therefore, it is believed that its mechanism of action does not concern the functioning of other organs of the reproductive system. In the official instruction of Viagra, which can be found on the FDA website, it is indicated that the use of Canadian Viagra’s oral dose of 100mg by healthy male persons didn’t result in any effect on sperm morphology or motility. We found that this conclusion is based on the study of K. Purvis and others, which was conducted as early as in 2002.

Moreover, the researchers found that the drug does not affect other sperm parameters:

• sperm density;
• quantity of abnormal forms of spermatozoa;
• percentage of living spermatozoa. 

However, later other researchers identified some changes. In 2007, the results of the study of Northern Ireland scientists D. Glenn (homepage) and others were released. To conduct the study, the Queen’s University researchers used sperm samples collected form forty five men who were Belfast fertility clinic attendees. They divided the samples into two halves. The first half was treated with sildenafil in vitro, while the second one was set aside as a control part.

In his interview given to the media, David Glenn, a member of the research team, said that sildenafil really increased the motility of spermatozoa, but also triggered a premature activation of the acrosome reaction of the sperm. This reaction is important for a female egg to be successfully impregnated. It occurs when enzymes located at the sperm head shoot out to go through the egg’s outer wall, allowing the sperm to enter.

The conclusion of the researchers was disappointing: "The use of sildenafil may adversely affect fertility in males."

But at the same time, David Glenn acknowledged that sperm is very sensitive if it is withdrawn from the natural environment. Therefore, the results of the study can’t be considered completed. Moreover, we do not know any well-known case reports about the deterioration of fertility due to the treatment with Viagra.

Can Viagra Improve Male Fertility?

F. Pellestor et al. (1994) found that prolonged sexual abstinence (more than 7 days) affects all semen parameters. Semen volume & sperm count showed significant increase, while sperm motility and morphology were decreased.

Let's have a look at the meanings of those terms.

1. Semen volume. According to the recommendations of the WHO (Examination & Processing of Human Semen) 2010, the lower limit of the norm of ejaculate volume is 1.5 ml. A small volume may indicate a partial/complete blockage of seminal vesicles due to their inflammation (vesiculitis).
2. Sperm count. Normal sperm should contain a certain number of male sex cells – at least 40 million. The minimum allowable concentration limit is 15 million per 1ml of seminal fluid.
3. Sperm motility. This term refers to the sperm’s ability to move in a proper way through the female reproductive tract with the purpose of reaching and fertilizing the egg. Although the most typical cause of infertility in male persons is low sperm count, in some men this problem is explained by low sperm motility. In healthy ejaculate, at least 40% of spermatozoa should be mobile.
4. Sperm morphology. It refers to shape and size of spermatozoa. A normal spermatozoon has an oval head & a long tail. Examples of abnormalities include a large head and a crooked tail. Usually, a large number of spermatozoa with an abnormal structure (anomalous shape, curvature of the cervix, etc.) are defined in sperm, but at least 4% of them should be normal.

It should be noted that all the mentioned parameters along with some others, such as pH level, fructose levels, and the presence of antisperm antibodies, are typically examined when a doctor checks fertility in a male. 

Sildenafil-based meds can positively affect fertility, increasing the frequency of sexual acts. This is due to the fact that impotence in men can lead to forced abstinence from sexual acts and deterioration of morphology and motility of sperm. Generic Viagra improves potency and allows a man to engage in full-fledged sex. Hence, this drug might indirectly improve sperm quality. 

Recent Chinese Research

A similar conclusion (on improving the quality of sperm) was recently made by Chinese scientists. Their review, which was first posted online, was published in “Urology” in 2017. The urologists from Sichuan University collected 11 studies, which involved more than 1,300 male participants, and conducted a quantitative analysis concerning the effect of ED drugs on those men’s fertility, in particular, their sperm quality. In the studies, examined by the researchers, the participants took ED drugs in the form of pills. Then their sperm samples were collected and thoroughly analyzed. Such features as sperm concentration, volume, morphology and motility were in focus of the research. The obtained results were sufficient to conclude that ED drugs didn’t have any effect on either sperm concentration or volume of semen. On the other hand, both the morphology and motility of the sperm samples analyzed improved. This conclusion does not comply with that drawn as a result of the Irish scientists’ study, which has been described above.

It cannot be said exactly that these effects will be felt by every man taking sildenafil-based drugs. But ED itself can be the cause of infertility, because this disease interrupts or inhibits sexual intercourse. By treating ED, the drugs eliminate the cause of infertility (if the infertility was caused by ED).

The Bottom Line on Viagra and Male Fertility

Studies on Canadian Viagra and male fertility are controversial. First, the researchers found that the drug did not affect male sperm. Then, other scientists suggested that it could worsen fertility due to activation of the premature reaction of spermatozoa before fertilization of the egg. Finally, a third group of researchers recently discovered that Viagra could even improve fertility.

Who should you believe?

We think that the truth, as usual, lies somewhere in between.

However, Viagra can positively affect sperm quality indirectly because it treats ED and can increase the frequency of sexual acts.