Anne Truong MDMen's Sexual Health Doctor

Morning Wood Happens at NIGHT #morningwood #nocturnal #sleephealth #rem

19 Jan 2026 · 1 min

Watch on YouTube

0:48

Short YouTube monologue (by Anne Truong MD) explaining why "morning wood" happens at night: it begins in adolescence with rising testosterone, occurs during REM (dream) sleep while the parasympathetic nervous system is active, typically happens 3–6 times per night with the largest on waking, and involves parasympathetic nerve stimulation releasing nitric oxide and increasing penile blood flow.

Questions this video answers

Between 3 and 6 per night.

In adolescence when testosterone rises.

During REM (rapid eye movement) sleep.

Chapters

Let me start with the first. That is the morning of. And you've had that probably since you're an adolescent. Right. When you start making testosterone and puberty and morning of usually happen at nighttime, actually. And you can have between three to six at night, with the most prominent one in the morning when you wake up. However, it only happens when you're in a dreamlike state called rapid eye movement, and that is spontaneous. So it happens when you are asleep, because that's when you're in deep sleep, you're dreaming, and you're in a parasympathetic state. And when you're in a parasympathetic state, the nerve is stimulated, you're releasing nitric oxide, you're increasing blood flow. Therefore.