The prostate is a small gland, roughly the size of a walnut, that sits just below the bladder in people assigned male at birth. It weighs about 1 ounce (30 grams) and wraps around the upper portion of the urethra, the tube that carries urine out of the body. Despite its small size, the prostate plays a central role in both urinary function and reproduction, and it becomes a common source of health problems as men age.
Where the Prostate Sits
The prostate is tucked between two landmarks: the bladder above it and the rectum behind it. Because it surrounds the urethra like a ring, any change in its size directly affects how easily urine can flow. A thin sheet of connective tissue called the prostatic fascia wraps around the gland and holds it in place, similar to a casing around a sausage. The gland’s position in front of the rectum is also why doctors can feel it during a physical exam by inserting a gloved finger into the rectum.
What the Prostate Does
The prostate’s primary job is producing a fluid that mixes with sperm to create semen. This prostatic fluid makes up a significant portion of ejaculate and does several things at once. It contains zinc, which kills bacteria and protects sperm from chromosomal damage. It carries enzymes that help sperm swim through cervical mucus and penetrate an egg. And it contains nutrients and antioxidants, including vitamin C, vitamin E, selenium, and carnitine, that shield sperm from oxidative damage during their journey.
Prostatic fluid also neutralizes the naturally acidic environment of the vagina, which would otherwise kill sperm before they could reach an egg. Without a healthy prostate producing this fluid, fertility drops substantially.
How Hormones Control Prostate Growth
The prostate depends on androgens (male sex hormones) to develop and maintain itself. Testosterone circulating in the blood gets converted into a more potent form called DHT inside prostate cells, and DHT is the primary driver of prostate growth. This is true during puberty, when the prostate first develops, and remains true throughout life. Men who lack functional androgen receptors due to genetic conditions never develop a normal prostate, and men who are castrated do not experience prostate enlargement with age.
This hormonal relationship is also the basis for one class of treatments for prostate problems. Medications that block the conversion of testosterone to DHT can shrink an enlarged prostate and relieve symptoms in some patients.
How the Prostate Changes With Age
One of the most predictable things about the prostate is that it grows. A walnut-sized gland at age 25 can reach the size of a lemon by age 60 or 70. This non-cancerous growth is called benign prostatic hyperplasia (BPH), and it is extraordinarily common. About 50% of men between ages 51 and 60 have it. That figure rises to 70% among men in their 60s and roughly 80% of men over 70.
Because the prostate surrounds the urethra, even modest enlargement can squeeze the urinary channel and produce noticeable symptoms:
- Frequent or urgent need to urinate, especially at night
- Trouble starting a stream or a weak, stop-and-start flow
- Dribbling at the end of urination
- Feeling like the bladder isn’t fully empty after finishing
Less commonly, BPH can lead to urinary tract infections, blood in the urine, or a complete inability to urinate, which is a medical emergency. Not every man with an enlarged prostate develops bothersome symptoms, but those who do have a range of treatment options from medications to minimally invasive procedures.
Prostatitis: Inflammation of the Prostate
Prostatitis is distinct from age-related enlargement and can affect men at any age. There are four recognized types, but the two most relevant to most people are acute bacterial prostatitis and chronic prostatitis (sometimes called chronic pelvic pain syndrome).
Acute bacterial prostatitis comes on suddenly and hits hard. Symptoms include fever, chills, body aches, burning during urination, and pain in the groin or lower back. It happens when bacteria travel up the urethra and infect the gland. It responds well to antibiotics but needs prompt treatment.
Chronic prostatitis is far more common and far more frustrating. Its exact cause is unknown, though it may involve immune system dysfunction, nerve damage, or chemicals in the urine rather than active infection. The hallmark is pain lasting three months or longer in the area between the scrotum and anus, the lower abdomen, the penis, or the lower back. Pain during or after ejaculation is another frequent symptom. Urinary urgency, frequency, and a weak stream often accompany the pain. Chronic bacterial prostatitis, a third type, produces similar but milder symptoms that come and go over years. A fourth type causes inflammation detectable in lab tests but produces no symptoms at all.
Prostate Cancer Risk Factors
Prostate cancer is one of the most common cancers in men. The three strongest risk factors are older age, African American race, and a family history of the disease. African American men are diagnosed at higher rates and tend to develop more aggressive forms. Having a father or brother with prostate cancer roughly doubles an individual’s risk.
Prostate cancer often produces no symptoms in its early stages, which is why screening has been a subject of ongoing debate.
How the Prostate Is Checked
Two tools form the backbone of prostate evaluation. The first is a digital rectal exam, where a doctor feels the gland through the rectal wall. They’re checking the size, surface texture, and whether any hard lumps or nodules are present. A normal prostate feels smooth and slightly rubbery. The exam takes seconds and, while uncomfortable, is not painful for most men.
The second tool is a blood test measuring prostate-specific antigen (PSA), a protein produced by prostate cells. For men in their 40s and 50s, a PSA above 2.5 ng/mL is generally considered elevated, with the typical level for that age group sitting around 0.6 to 0.7 ng/mL. For men in their 60s, the threshold rises to 4.0 ng/mL, with a normal range between 1.0 and 1.5 ng/mL. An elevated PSA does not mean cancer is present. Infections, BPH, and even recent physical activity can push the number up.
Current Screening Recommendations
The U.S. Preventive Services Task Force recommends that men aged 55 to 69 make an individual decision about PSA screening after discussing the potential benefits and harms with their doctor. Screening can catch cancer early, but it can also lead to biopsies and treatments for slow-growing cancers that might never have caused problems, and those treatments carry real side effects. For men 70 and older, the Task Force recommends against routine PSA screening.
Men at higher risk, particularly African American men and those with a family history of prostate cancer, may benefit from starting the conversation about screening earlier, sometimes in their 40s. The decision ultimately depends on personal values, overall health, and how an individual weighs the tradeoffs between early detection and the possibility of unnecessary treatment.