There’s no reason to be concerned if your semen suddenly appears thick.

Many people have naturally thick semen. You should only keep an eye on it or consider seeing your doctor if you experience other symptoms.

Here's what to watch for, what could be behind the texture change, and when to see your doctor.

Semen texture varies widely from person to person. Your unique biology can affect the smell, taste, and texture.

Semen texture can change based on your:

Some habits, such as smoking marijuana or drinking alcohol, can also affect your semen volume and texture. These habits lower sperm count and sperm concentration in a single ejaculation, as well as lower overall testosterone levels.

Ejaculation changes texture as soon as it leaves the penis. It often starts off thick and warm, but becomes watery and cool after being exposed to the air for a few minutes.

Frequent ejaculation can lower your semen volume and the amount of sperm that leaves your body during a single ejaculation. Both factors can affect the consistency of your semen.

Thick semen usually results from a higher than normal concentration of sperm in a typical volume of semen, or from having a high number of sperm with an irregular shape (morphology).

High sperm concentration often indicates that you’re more likely to impregnate a female partner. Thick semen is also less likely to drip out of the vagina. This increases you and your partner’s chance of conception.

Healthy semen typically has the following characteristics:

Keep in mind that what’s considered healthy can vary from person to person. If you meet most of these baselines, there’s no need to worry about how thick your semen is.

If your semen isn’t normally thick and clumpy, this texture might be caused by:

Dehydration

Semen is composed primarily of water. Not getting enough fluids can reduce the amount of liquid available to give semen its typically viscous texture.

Drinking enough water throughout the day helps regulate your body’s pH level. This is your body’s relative balance of acidic and alkaline substances.

Your body typically maintains a pH level of 7.4. When you’re dehydrated, your pH levels can become irregular. This can make your semen thick and affect many other organs in your body, too.

Other signs and symptoms of dehydration include:

  • extreme thirst
  • exhaustion
  • dizziness
  • confusion
  • infrequent urination
  • dark urine
  • dark or bloody stool

Hormonal imbalance

Semen contains many hormones. This includes many androgens like testosterone and some other steroid hormones intended to protect sperm as they travel through the acidic environment of the vagina. Your age, diet, and level of physical activity can all impact your hormone levels.

Hormonal imbalance can result in thickened semen, as well as irregularly shaped sperm. Irregular sperm shape can also contribute to your semen’s texture.

Other symptoms of hormone imbalance include:

  • reduced sexual desire
  • difficulty getting or keeping an erection
  • loss of body or facial hair
  • exhaustion
  • loss of muscle mass
  • abnormal weight loss
  • increase in body fat

Infection

Genital tract infections, especially bacterial infections, can make your semen thick. This is because they increase the number of white blood cells to the area. This can decrease how much semen you produce. It can also reduce sperm concentration in your semen and affect sperm shape.

A 2003 study even suggests that the presence of infectious bacteria in your genital tract can cause white blood cells to attack sperm. This can influence the thickness of your semen.

A 2009 study also indicates that infectious bacteria can cause sperm to stick together. This also contributes to how thick your semen is.

Other signs and symptoms of infection include:

  • difficulty urinating
  • pain or burning during urination
  • bloody urine
  • abnormal clear or cloudy discharge
  • swollen testicles

See your doctor as soon as possible if you notice any pain, discomfort, or fatigue along with recently thickened semen.

Some causes, such as infections, will go away with proper antibiotic treatment, so seek medical care. If you’re experiencing unusual symptoms in addition to thick semen, especially a fever over 101°F (38.3°C), get immediate medical attention.

Symptoms that affect your genitals, such as pain during urination, unusual discharge, and swelling, should be treated right away. These could be signs of a sexually transmitted infection.