Micropenis: Causes, Symptoms, Treatments

Medically Reviewed by Melinda Ratini, MS, DO on June 17, 2022
4 min read

“Is my penis too small?” That's a question that people aren't likely to ask their friends or sex partners.

But behind the closed doors of a doctor's examining room, it's a common question.

It’s quite common to worry about your penis size. Doctors refer to this as “small penis syndrome.” But in some cases, someone may be born with an abnormally small penis, or “micropenis.”

A micropenis is a medical term to describe a penis that’s much smaller than average. They’re caused by hormonal or genetic reasons. Micropenises are very rare. Studies show that globally, only 0.6% of people have the condition.

Your doctor will usually diagnose you with the condition if your penis has a stretched penile length (SPL) of 3.67 inches or under. An average SPL for adults is 5.25 inch long.

An early sign of micropenis is a penis that’s less than 0.75 inches in length at birth. The average SPL for a newborn is 1.4 inches.

At birth, you might have other complications alongside this disorder. This may be because of the hormonal issues related to micropenis. The specific symptoms will depend on the cause of the micropenis.

A micropenis usually happens because of a lack of fetal testosterone. This could be caused by many conditions, including one called hypogonadotropic hypogonadism. This disorder happens when your brain’s hypothalamus doesn’t make enough hormones to stimulate your testicles. Without these hormones, your testicles won’t create enough testosterone for regular penis growth and function.

In other cases, you could be born with a micropenis because of a genetic syndrome. Other cases may have no obvious reason at all.

Your doctor will diagnose you with micropenis through a physical exam. They usually find the condition when you’re an infant or a young child. Your doctor will measure your penis length and compare it to the average length of other people your age.

There isn’t a cure for micropenis. But if your doctor finds that your child has a micropenis, they can give them hormone therapy to help the penis grow. Your chances for successful treatment are greater if your doctor finds the condition when you’re an infant.

Your treatment will depend on the cause of your micropenis. Treatment options include:

Testosterone. This is what doctors use first to treat micropenis. They’ll give your child a brief course of testosterone. They’ll watch how the penis responds to the growth hormone. Your child’s doctor will either inject the testosterone or apply it as a gel or ointment.

If testosterone doesn’t help, your doctor might try other hormonal treatments.

Surgery. Doctors only consider this line of treatment if other options don’t work. Phalloplasty, or surgical reconstruction, of a micropenis for young children can be risky. Surgery for young adults and adults is a lot more common.

If a hormonal issue caused your child’s micropenis, their outlook is good. They’ll usually respond well to testosterone therapy. With treatment, they’ll notice penis growth. But it still may be slightly below average size.

Your outlook may not be as great if your micropenis happened due to other, nonhormonal disorders.

Inconspicuous penis means a penis that is hard to see. Micropenis is the rarest of the conditions under the umbrella term "inconspicuous penis."

Other forms of inconspicuous penis that may stay untreated until adulthood are webbed penis and buried penis.

A webbed penis is when your scrotum is connected to the underside of your penis. When this happens, it pulls your penis inward.

Buried penis happens when your penis is hidden below your skin. This can happen if too much belly fat in the front of your stomach droops down to cover the penis. It can also happen when the connection to your scrotum is gone and your penis goes inward toward your pelvis. Another form of buried penis happens when a too-large foreskin makes your penis look buried.

Doctors can treat webbed penis through surgery. Buried penis may require weight loss and liposuction. There are also surgical procedures that can correct the problem.

Penis size is a key element in your self-image. Although they may say otherwise in conversation, the average person greatly underestimates the relative size of their penis. You may have small penis syndrome if you worry a lot about your size, even if you have an average-sized penis.

Body dysmorphia disorder happens when you worry so much about how your body looks that it interrupts your daily life. If you have body dysmorphia or small penis syndrome, you may need professional psychological help. But most people only need reassurance that they really are normal.

Many people worry about the size of their erections. Many more worry about how their penis looks when it's limp, studies find.

One reason people often worry may be because they have no idea what a normal-size penis looks like. When asked to guess, most guess wrong.

Another reason is pornography. If you read or watch a lot of porn, you may have a distorted picture of normal anatomy.

You may be surprised to learn that penis length isn't measured on the erect penis. Too many variables are involved.

Instead, the most reliable penis measurement is through SPL. The longer the person’s SPL, the longer their erect penis length.

To learn your SPL, measure your penis while it's flaccid, or limp. Press the ruler tight against the pubic bone at the base of the penis. Don't just measure from where the penis separates from the scrotum. Now gently, but very firmly, stretch the penis as far as it will go. Measure from the pubic bone to the tip of the stretched penis.