A typical prostate is about the size of a walnut, but prostate enlargement is common with age.

The prostate is a part of the reproductive system. It’s a small gland positioned in front of the rectum, just below the bladder, surrounding part of your urethra. The prostate generates the fluid that transports sperm, known as “seminal fluid.”

Aging can bring about changes in the size of your prostate. The prostate can slowly become enlarged, and a variety of disruptive symptoms — especially related to emptying your bladder — are possible.

The average adult prostate is about the size of a walnut, weighing between 15 and 20 grams (g) with a volume of around 20–25 cubic centimeters (cc).

The prostate is made up of several anatomic zones:

  • transition zone
  • central zone
  • peripheral zone

Of these zones, the peripheral zone makes up the largest portion of the prostate. It’s the zone where most prostate cancers begin.

Noncancerous and age-related prostate enlargement, called “benign prostatic hypertrophy (BPH),” typically occurs in the transition zone, which is the zone that surrounds the urethra.

Language matters

You’ll notice that the language used to share stats and other data points is pretty binary, with frequent use of the term “men.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

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According to a 2021 review on prostate aging, your prostate starts to form around the 10th–12th week of gestation. During this time sex hormones, such as testosterone, stimulate cellular growth and differentiation in a developing fetus.

The prostate continues to grow for your first 6–9 months of infancy, during a time known as “minipuberty,” until it reaches approximately 10 g — half of the standard size of the adult prostate.

Your prostate stays at this size until you hit puberty.

While not everyone enters puberty at the same age, most people assigned male at birth begin this developmental phase between 9 and 14 years of age.

Throughout puberty, your prostate grows to the standard adult size of a walnut, finishing by the time you’re around 20 years of age.

You may never experience problematic prostate growth beyond 20 years, but, at approximately the age of 25 years, the prostate enters a second growth phase that continues throughout life and can contribute to BPH enlargement.

By the age of 40 years, your prostate may be as large as an apricot, and by the age of 60 years, it may be the size of a tennis ball, lemon, or larger.

BPH affects almost half of men more than 50 years of age and as many as 90% of men more than 80 years of age.

An enlarged prostate becomes dangerous when it prevents the proper flow of urine, potentially causing backflow that leads to bladder and kidney infections. In some cases, an enlarged prostate can block urine flow completely or result in kidney failure.

There’s no way to predict how quickly the growth of your prostate may affect your urinary tract. In some people, minor enlargement may cause serious symptoms, while other people may have lemon-sized prostates with minimal complications.

In general, the American Urological Association recommends surgical intervention for prostates that have a volume of 30 cc or larger with notable lower urinary symptoms.

As your prostate enlarges, it puts pressure on surrounding tissues.

Because BPH typically affects the transition zone surrounding the urethra, it often causes symptoms related to urethra and bladder compression.

Common symptoms of an enlarged prostate include:

  • frequently urinating throughout the day
  • urinary urgency
  • difficulty initiating urination
  • weak or interrupted urine stream
  • urinary incontinence
  • getting up frequently at night to urinate
  • dribbling at the end of urinating
  • unusual urine color or smell
  • pain during urination or ejaculation

You may also feel as though you haven’t emptied your bladder fully or can’t urinate when you need to.

There’s no cure for age-related and noncancerous prostate enlargement, but treatment may help you manage symptoms. Some people can find relief through lifestyle changes that help to proactively address urinary complications.

Many people find they can manage mild symptoms by:

  • using the bathroom regularly before needing to go
  • emptying your bladder completely each time you urinate
  • limiting drinks before bedtime
  • avoiding alcohol or caffeine

When symptoms can’t be comfortably relieved with lifestyle changes, medications and surgery options are available.

Doctors use two primary types of medications for the treatment of BPH:

  • Alpha-blockers: medications that relax the muscles around the prostate
  • 5 alpha-reductase inhibitors: medications that help shrink the size of the prostate by altering the hormones that stimulate prostate growth

Surgery is generally reserved for enlarged prostates that don’t respond to medication therapy or lifestyle changes. A variety of surgical approaches exist, all with the goal of removing excess prostate tissue.

A doctor will select the surgery type that best fits your current prostate size, symptoms, and overall health.

Minimally-invasive procedures through the urethra include:

  • transurethral resection of the prostate
  • transurethral incision of the prostate
  • transurethral needle ablation
  • transurethral electroevaporation of the prostate
  • transurethral microwave thermotherapy
  • laser surgery

Another surgery option is prostate surgery (prostatectomy), which involves an incision in your skin to remove all or part of the prostate. There are several types of prostatectomies, and a doctor will choose which incision point makes the most sense for you.

It’s not always necessary to treat an enlarged prostate, but an untreated enlarged prostate can cause complications, such as:

BPH is only one potential cause of prostate enlargement. Prostate cancer and inflammation of the prostate gland, called “prostatitis,” are also reasons your prostate may be enlarged.

Speaking with a doctor is the only way to rule out these other conditions.

Symptoms not to ignore

An enlarged prostate can become a medical emergency when it completely blocks urine flow or leads to kidney failure.

Seek immediate medical attention by calling 911 or local emergency services if you’re experiencing:

  • fever and chills accompanying painful urinary symptoms
  • complete inability to eliminate urine
  • intense abdominal or urinary pain
  • blood in your urine
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The average adult prostate gland is about the size of a walnut, but prostate growth throughout life may cause your prostate to more than double in size.

Not all age-related prostate growth will cause problematic symptoms, but many people experience urinary challenges as growing prostate tissue puts pressure on the bladder and urethra.

Lifestyle changes may help relieve mild symptoms of an enlarged prostate. For more severe cases, medications and surgical options are available.