What is the prostate?

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Chimene Richa, MD 

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Chimene Richa, MD 

last updated: Dec 09, 2021

6 min read

When you hear about your prostate, it’s usually because something is wrong with it. This walnut-sized gland is so well known for the problems it causes that most people don’t know what it’s there in the first place. We'll get to some of those problems in due course, but first, let's first get familiar with what the prostate is, where it is, and what it does. 


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What’s a prostate?

The prostate gland is an essential part of the male reproductive system. It sits in the spot between your butt and your penis, right under your bladder. 

Because of its location, you can actually feel the prostate by inserting a finger into the rectum. While the prostate gland is commonly described as "walnut-sized," it’s actually only accurate in men in their 20s. The prostate increases in size as men get older, measuring the size of an apricot by the time they hit their 40s and the size of a lemon by the time men hit 60.

The urethra, the tube that carries urine from the bladder out through the penis when you pee, actually runs through the prostate. That's why a growing prostate can make it tough to pee. But we’ll get into that later.

Prostate gland function

The prostate gland’s main role is to make and secrete prostatic fluid, one of the components of semen. This fluid both transports sperm cells and keeps them healthy. The prostatic fluid typically accounts for up to about a third of semen volume. Around 60% of semen comes from the seminal vesicles; only 5% of semen is actual sperm cells (Lawrentschuk, 2016; NCI-b, n.d.).

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During ejaculation, muscle cells inside the prostate contract and forcefully press the fluid that has been stored in the prostate out into the urethra. Here, the prostatic fluid combines with sperm and fluid from other glands to form semen immediately before ejaculation. 

Understanding changes in prostate function

It’s normal for the prostate to grow in size throughout a man’s life. The prostate goes through two main growth periods, the first of which happens early in puberty when the prostate doubles in size. The second growth phase usually starts around age 25 and continues throughout most of a man’s life (NIDDK, 2014). 

Many men report needing to get up to pee more often during the night than they did when they were younger, and a lot of the time, an increase in the size of the prostate is the cause of their nighttime urination, also known as nocturia.

A growing prostate can cause various urinary problems (lower urinary tract symptoms or LUTS). Some of these will be manageable, while others can take a real toll on your quality of life. Regardless of how common lower urinary tract symptoms are, it’s a good idea to discuss them with your healthcare provider since there are many treatments available to alleviate your symptoms. 

Most common prostate problems

As men age, the risk of prostate problems increases. The most common issues are prostatitis, benign prostatic hyperplasia or benign prostatic hypertrophy (BPH), and prostate cancer. 


The suffix "itis" means inflammation. Prostatitis, then, means inflammation of the prostate gland. With this condition, the prostate can become swollen and tender. 

There are four main types of prostatitis (NCI-a, n.d.):

  • Acute bacterial prostatitis is an infection that develops rapidly, but it’s also easy to treat. Common symptoms include fever and chills, as well as blood in the urine. Treatment usually involves a 2–4 week course of antibiotics (Nickel, 2011). 

  • Chronic bacterial prostatitis is also caused by bacteria but develops slowly. One of the main symptoms is having bladder infections that keep coming back. 60–80% of patients improve after taking antibiotics for several weeks.  

  • Chronic pelvic pain syndrome (CPPS) has symptoms that vary from person to person and include urination problems, pain with ejaculation, and pelvic pain. Treatments are based on your symptoms and include anti-inflammatory medications, medications known as alpha-blockers, and antibiotics (Pirola, 2019).

  • Asymptomatic inflammatory prostatitis has no symptoms but is often discovered while testing for other conditions. Because it is asymptomatic, treatment is generally not necessary.

Enlarged prostate (aka benign prostatic hyperplasia or BPH)

Benign prostatic hyperplasia or hypertrophy (BPH) is a non-cancerous (benign) enlargement of the prostate gland. It usually affects older men. About 50% of men between the ages of 51 and 60 have an enlarged prostate, and the rate increases with age. Up to 90% of men over 80 years of age are affected by BPH (Kim, 2016; Urology Care Foundation, 2019). Other than age, risk factors for developing BPH include obesity, family history, atherosclerosis, and type 2 diabetes. 

The growth in BPH is mainly in the part of the prostate around the urethra, which carries urine out of the bladder when you pee (an area called the transitional zone). As the prostate gets bigger, it can put pressure on the urethra and the bladder base. 

This can cause symptoms known as LUTS (lower urinary tract symptoms), which include: 

  • Needing to urinate frequently

  • Needing to urinate more often at night (nocturia)

  • Trouble starting urination

  • Feeling like your bladder is full, even after you have just finished urinating.

  • A weak urine stream

  • Starting and frequently stopping during urination

  • Having to strain to urinate

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Some men develop symptoms of BPH, while others don’t, and we’re not entirely sure why. Some experts believe that a family history of the condition increases a person’s risk of developing BPH. You may have heard that frequency of sex and having a vasectomy might increase someone’s chances of developing BPH—rest assured, there’s no evidence to support that claim (McVary, 2020). 

The exact cause of BPH is unknown, but testosterone (T) and a more potent form of the hormone called dihydrotestosterone (DHT) are involved in both normal prostate growth and abnormal growth, such as the growth that occurs in prostate cancer. 

There are several theories regarding why these two male hormones are involved in both normal and abnormal growth. 

  • One theory is that, as men age, testosterone in their blood decreases, making estrogen a more dominant hormone. This higher estrogen-to-testosterone ratio may encourage prostate cell growth (Ho, 2011). 

  • Another theory is that falling testosterone levels lead to an increase in DHT levels, which may also increase prostate cell growth (Rastreilli, 2019). 

  • Lastly, chronic inflammation is thought to play an increasing role in this condition (Vignozzi, 2014). 

It’s most likely that a combination of these things leads to prostate growth. 

A BPH diagnosis usually starts with a history of lower urinary tract symptoms (LUTS). The goal of treating BPH is to improve the quality of life of patients suffering from LUTS. The American Urological Association (AUA) recommends watchful waiting for patients with mild symptoms or mild-moderate symptoms with a minimal decrease in their quality of life (McVary, 2011).

Watchful waiting involves yearly physical exams, including a digital rectal exam (DRE), education, and modification of lifestyle risk factors, such as limiting the consumption of caffeine and alcohol, maintaining a healthy weight, and exercising regularly.

You can learn more about BPH treatment options here

Prostate cancer 

After skin cancer, prostate cancer is the most common cancer in men in the United States. The American Cancer Society estimates that just this past year, 248,530 received a new diagnosis of prostate cancer, and about 34,130 died from the disease (ACS, 2021-a). One of the most significant risk factors for prostate cancer is age. In men younger than 40, prostate cancer is rare—but the chance of having prostate cancer rises significantly after the age of 50.

Prostate cancer is more common in people who are Black, as well as those with a family history of the disease, smokers, and people who consume a diet high in saturated fat (ACS, 2021-a). Often, prostate cancers grow slowly and may not cause symptoms for years—or ever. That’s why many men can have prostate cancer and not even know it. 

Your healthcare provider may suspect prostate cancer based on symptoms or the results of a digital rectal exam (where they insert a finger into the rectum to check the size, shape, and firmness of the prostate). The PSA test, which measures the level of a particular substance in your blood, can also help. But diagnosis requires a tissue biopsy, during which a small needle is used to collect samples from the prostate, which are later examined under a microscope.

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In Western countries, the majority of prostate cancers are detected through prostate cancer screening. Men should make a shared decision with their healthcare provider about whether to be screened for prostate cancer or not. The question is when to have that conversation. Most men should ask their healthcare provider about prostate cancer screening at age 50. However, men at higher risk for prostate cancer, including Black men and men with a family history of prostate cancer, should have that conversation with their healthcare provider at age 45 (ACS-b, 2021).

Prostate testing

Your healthcare provider will likely recommend certain tests if you’re experiencing symptoms of these common prostate problems. The most common tests they’ll recommend include: 

Prostate specific antigen (PSA) test

The PSA test is a simple blood test that some healthcare providers run routinely based on age. PSA is a substance produced by the prostate, so as the prostate grows when you get older, the numbers naturally go up. For that reason, the significance of your test results varies with age. 

It’s also important to remember that things like BPH, trauma (like from vigorous sex or exercise), infection, and inflammation, can all cause your PSA values to rise.

There are no precise values for PSA, but it can be a good tool for your provider to decide whether or not more testing is necessary. The currently accepted ranges for PSA are as follows, and levels higher than this for your age range might be enough to warrant more testing:

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Prostate biopsy

If your PSA levels are on the higher side for your age range, if the results of any other evaluations are out of normal range, or your symptoms worsen after watchful waiting, your healthcare provider may recommend a biopsy. With a biopsy, a surgeon will remove a small piece of tissue from the prostate, which will then be evaluated under a microscope to look for the presence of cancerous cells. 

You can learn more about prostate cancer diagnosis and treatment here

The prostate gland is a vital part of the male reproductive system. Prostate conditions are very common, especially as men get older. It is important to pay attention to any urinary or sexual symptoms and discuss any changes with your healthcare provider.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

December 09, 2021

Written by

Chimene Richa, MD

Fact checked by

Yael Cooperman, MD

About the medical reviewer

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.