Thick semen is not always a cause for concern, especially if this consistency is infrequent. However, if semen is often very thick, it may signal a problem with the prostate or the seminal vesicles.

The consistency of semen varies from person to person. It can also change over time or even from one ejaculation to another.

If a person has very thick semen, a doctor may refer to the issue as “semen hyperviscosity.

If semen is very thick, the sperm cannot move as easily and there may be fewer sperm. As a result, it may be difficult to impregnate a partner.

In this article, we explore the causes of thick semen, describe when to see a doctor, and provide some tips for keeping the sperm healthy.

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Infrequent ejaculation is a possible cause of thick semen.

It can be difficult for a person to tell whether their semen is unusually thick. Healthy semen begins thickening and hardening just after ejaculation.

Only a semen analysis test that includes a viscosity test can tell for sure.

A person may need testing and medical attention if their semen:

  • seems much thicker than usual
  • comes out in thick strands instead of drops
  • comes out very solid or in chunks

Around 12–29% of males have semen that clinically qualifies as thick, according to a 2013 analysis.

Semen might become this thick due to:

Infrequent ejaculation

When a person ejaculates after not having done so for a long period, they may find an increase in the thickness and total amount of semen.

Anyone who feels concerned about the thickness of their semen should consider ejaculating every few days.


If the body is not properly hydrated, there may be less water in the semen, causing it to be thick or chunky.

Anyone who wonders whether the thickness of their semen results from a health issue should drink plenty of water and see whether this resolves the issue.


Leukocytospermia is a condition characterized by ejaculate with too many white blood cells — cells that typically help fight infection. It can diminish a male’s fertility.

The condition can develop for no apparent reason, or it can occur when a person has an infection, such as one in the urinary tract or a sexually transmitted infection (STI).

Oxidative stress may also cause leukocytospermia. Over time, especially as a person ages, free radicals and reactive oxygen species may accumulate in the genital tract. In response, white blood cells may build up in the reproductive tract, and there may be inflammation.

Usually, a doctor treats leukocytospermia with antibiotics, and antioxidants, which combat oxidative damage, may also help.

Whether these interventions increase the chances of pregnancy remains unclear.

Problems in the prostate or seminal vesicles

Semen is made up of sperm from the testicles, seminal fluid from the seminal vesicles, and a small amount of fluid from the prostate. The semen then travels through the ejaculatory ducts and into the urethra, where it is ejaculated.

Problems with the functioning of either the prostate or seminal vesicles may make the semen unusually thick.

Specifically, the thickness may indicate that an issue in the seminal vesicles is causing the prostate to secrete more fluid or that there has been a change in the proteins that the prostate and seminal vesicles add to semen.

Some people may experience other symptoms of prostate problems, such as painful ejaculation, pain when urinating, or frequent urination.

It is usually not possible to assess semen’s health by how it looks or feels.

Very thick semen may reduce sperm movement or count, but many people with low sperm counts have semen that seems normal. The only way to reliably assess semen is with a professional analysis.

After a person gives a semen sample, their doctor sends it to a laboratory. The results show several measures of semen health, including:

  • Semen volume: This is a measure of how much semen a person produces, which should be 1.5 to 5 milliliters.
  • Concentration: Sometimes called sperm count, this is a measure of how highly concentrated sperm are in the semen sample. An ideal number is 15–20 million or higher.
  • Morphology: This indicates whether the shape and appearance of the sperm are healthy. If fewer regularly shaped sperm are present in a sample, this indicates a lower chance of successful impregnation.
  • Motility: This measures how many sperm can move properly. Healthy males should have motility numbers of 40–50%.

Even healthy people can have problems with their sperm or semen, and a person can take steps to improve their semen quality.

For example, a person can try taking antioxidants. Oxidative damage may contribute to thick sperm or infections, and a handful of small studies have found that taking over-the-counter supplements of antioxidants such as vitamin C, vitamin E, or coenzyme Q, led to improvements in sperm count or semen quality.

It is also a good idea to avoid very high temperatures, which may damage sperm, by staying away from saunas and Jacuzzis.

Also, it may help to:

  • Wear loose-fitting pants and underwear.
  • Maintain a healthy body weight.
  • Reduce alcohol consumption.
  • Quit smoking.
  • Eat a wide variety of fruits and vegetables.

A person should receive medical attention if:

  • Their sperm is unusually thick for more than a few days and does not respond to home care strategies, such as drinking more water.
  • Other symptoms, such as painful or frequent urination or painful sex, also occur.
  • They recently had unprotected sex with someone whose STI status was unknown or if they have not had an STI test in the last 6 months.
  • They are unable to get a partner pregnant after 6–12 months of trying.

Semen consistency, volume, quality, and even color can change from day to day, and they vary naturally from person to person.

Only a healthcare professional can assess whether thick semen indicates a health issue.

Anyone who notices a consistent, unexplained change in their semen should receive medical attention, especially if they are concerned about fertility or experiencing any other symptoms.