Everything You Need to Know About Morning Wood

Medically Reviewed By Kevin Martinez, M.D.
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Morning wood, or nocturnal penile tumescence (NPT), is a common occurrence for many people. It is a spontaneous erection that can happen in the middle of the night or early morning while you are asleep. This can lead to you waking up with an erection. It is common to associate an erection with sexual stimulation, but this is not always the reason behind experiencing an erection. There are many naturally occurring causes for this response.

This article will explain what morning wood is, why it happens, and if you should contact a doctor.

What is morning wood?

man laying in bed
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Morning wood is a spontaneous erection that can happen in the early morning while you are asleep or in the middle of the night.

It is natural for men of all ages to experience nocturnal penile tumescence, or morning wood. At any age, it is healthy and a good sign of an effective vascular and nervous system in and around the pubic area.

You can experience NPT from infancy all the way through to your 60s and 70s. However, it is common for the frequency of these experiences to decline as you age and if you begin to experience erectile dysfunction.

Read more about erectile dysfunction here.

Morning wood vs. ‘wet dreams’

NPT is the act of developing an erection during sleep. A “wet dream,” medically referred to as nocturnal emission, is experiencing an orgasm during sleep. Usually, a wet dream occurs when you are already erect and experience a sexual dream.

What causes morning wood?

There are many causes of morning wood. There are a few theories to help explain why you may wake up with an erect penis, but there is no confirmed evidence.

Physical stimulation

Even if you are asleep, your body is still aware of physical touch. If you roll over in bed, and you or your partner briefly touch your pubic area, you may become erect. Your nervous system will sense the stimulation and respond.

Hormonal shifts

Your hormones cycle through the night, with your levels of testosterone peaking in the morning. More specifically, as soon as your REM (rapid eye movement) sleep stage starts your testosterone peaks.

You experience several REM sleep cycles a night, so you will be largely unaware of any erections you have during the night. But in the morning, you are most likely to awaken directly out of a REM stage. This is why NPT is associated with the morning.

An increase in this hormone alone may be sufficient to cause an erection, even if there is no physical interaction.

As you age, your testosterone levels usually fall. As testosterone declines, experiences of NPT may also decrease.

While there is confusion about what may cause NPT, it is getting clearer as to what is not responsible.

For example, the urge to urinate does not cause NPT.

Is it a sign of good health?

Experiencing nocturnal penile tumescence is commonly considered a sign of good nerve and vascular health. The blood vessels in your penis are much smaller than the rest of your body.

This means that any underlying health issues are likely to show up first as erectile dysfunction. This can include:

If you experience erections that last longer than 2 hours, also known as priapism, you should seek medical advice as soon as possible.

When should you contact a doctor?

If you see a significant decline in your frequency of experiencing morning wood, it is important to acknowledge it. Loss of morning wood can be an important indication of a health condition and not just a sexual health concern.

Some conditions this can indicate include:

It is also important to seek medical advice if you start to experience painful erections, otherwise known as priapism.

This can be a sign of some of the following conditions:

  • blood disorders
  • side effects of medications
  • trauma to the penis
  • infection of the urinary tract
  • hormonal abnormalities

Despite these conditions, the most common reason for painful erections is Peyronie’s disease. Scar tissue forms under the skin of the penis, causing curvature of the penis.

Read more about Peyronie’s disease here.


Morning wood indicates a healthy nervous and vascular system around the pubic area and the penis.

You may experience NPT multiple times a week. As you age, this decreases in frequency, possibly as your testosterone levels drop.

If you see a sudden decline in the frequency of NPT, seek advice from a medical professional. The drop can indicate a health condition such as heart disease, depression, or a side effect of medication.

Keep paying attention to the frequency in which you experience morning wood.

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Medical Reviewer: Kevin Martinez, M.D.
Last Review Date: 2022 Jul 29
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