Penis shrinkage: Causes, treatment, and why it happens

Penis shrinkage can occur and is often due to age, medication side effects, or lifestyle habits, such as smoking or weight gain. It rarely requires treatment, and habit changes can often help.

Penis size can vary significantly between people, and certain lifestyle factors can affect it.

This article discusses the current research on average penis sizes, what may cause shrinkage, and available treatment options.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Learn more.

Research into average penis sizes is often impaired by inaccurate participant reporting, selection bias, and inadequate sample sizes. However, a 2020 review calculated that the average penis size was:

• Erect: 13.61 cm (5.36 inches)
• Flaccid, pulled: 12.98 cm (5.11 inches)

Older but more detailed research from

• Average length of a flaccid penis: 9.16 centimeters (3.6 inches)
• Average length of a flaccid stretched penis: 13.24 cm (5.3 inches)
• Average length of an erect penis: 13.12 cm (5.2 inches)
• Average circumference of a flaccid penis: 9.31cm (3.7 inches)
• Average circumference of an erect penis: 11.66 cm (4.6 inches)

Penis shrinkage is widespread as men age, but there are many other reasons why a penis may shrink:

Aging

Furthermore, fatty deposits can build up in the arteries (atherosclerosis), causing reduced blood flow to the penis, and a natural reduction in testosterone can further decrease erection size and strength.

Learn about erectile dysfunction and aging.

Weight gain

Weight gain, particularly around the abdomen, may also impact perceived penis size.

Although a penis may appear smaller with weight gain, it has not shrunk. It looks smaller because the penis is attached to the abdominal wall, and when the belly expands, it pulls the penis inward. If a person loses weight, their penis will regain its shape and size.

Prostate surgery

Research from 2014 found that penis shrinkage occurred in

However, more recent reviews note that penile shrinkage rates tend to lessen the further on from surgery recovery a person gets. Researchers found that around

Peyronie’s disease

In Peyronie’s disease, fibrous scar tissue develops inside the penis, causing it to

Peyronie’s can cause a reduction in the length and circumference of a penis. Sometimes, Peyronie’s goes away on its own; most of the time, however, it will either stay the same or worsen.

Medications

Studies have found penile shrinkage and other sexual dysfunctions to be a side effect of finasteride and dutasteride, common anti-baldness medications.

According to Harvard Medical School, some medications can also reduce blood flow to the penis, and affect sexual performance, including the strength and size of erections. These medications include anti-hypertensives and selective serotonin reuptake inhibitors.

Smoking

Smoking is also associated with erectile dysfunction, according to an

Chemicals from cigarette smoking can injure the blood vessels in the penis, preventing the penis from filling with blood and stretching. Regardless of the stimuli and the effect on the brain, if the blood vessels are damaged, the penis will not maintain an erection.

Most causes of penis shrinkage, such as smoking and weight gain, can be addressed by lifestyle changes. If medications are causing the penis to shrink, a medication adjustment can reverse the shrinkage.

For some men who experience penis shrinkage after prostate removal, the condition may improve on its own within a few months to a year. Penile rehabilitation (a form of physical therapy) after surgery can help men regain erectile function, and medications, such as sildenafil (Viagra) and tadalafil (Cialis), can boost blood flow to the penis.

Treatment for Peyronie’s disease

Most of the time, penis shrinkage is related to age, medication, or lifestyle habits, such as smoking or weight gain, and rarely requires treatment. Adopting more healthier lifestyle habits or changing medication can often reverse shrinkage and reduce other sexual problems.