There are so many things that can ultimately affect your sleep quality. You may not be aware that various hormones and chemicals can play a substantial role in sleep—and in your overall health. Serotonin is one of these hormones.
When it comes to sleep, serotonin is the thread that weaves together one’s mood, energy, and ability to rest, says Christopher Allen, MD, sleep science advisor at Aeroflow Sleep, board-certified sleep medicine physician, and pediatric neurologist.
“By nurturing serotonin through healthy lifestyle choices, you’re not just improving sleep—you’re enhancing your overall quality of life,” he says.
But what exactly is the connection between serotonin and sleep? Ahead, we’ll explore everything you need to know about serotonin and its impact on sleep.
What is serotonin?
Serotonin is a neurotransmitter, or a chemical messenger, that plays a key role in mood, emotions, digestion, and sleep, explains Allen.
“It’s primarily produced in the gut but also acts in the brain, helping regulate various bodily functions,” he says. “Often referred to as the ‘feel-good’ neurotransmitter, serotonin promotes a sense of well-being and calm.”
Serotonin is a neurotransmitter, or a chemical messenger, that plays a key role in mood, emotions, digestion, and sleep.
The role of serotonin in sleep
“Serotonin is deeply intertwined with sleep regulation,” says Allen. “It contributes to the onset of sleep by calming the brain and is a precursor to melatonin—the hormone that governs the sleep-wake cycle.”
Higher serotonin levels are associated with deeper, more restful sleep, while low levels can contribute to insomnia or fragmented sleep patterns, he adds.
When it comes to circadian rhythm, Allen says serotonin helps set and stabilize circadian rhythms by influencing the suprachiasmatic nucleus (SCN), or the brain’s master clock.
“During daylight, serotonin levels rise, promoting alertness and mood,” he says. “As evening approaches and light diminishes, serotonin is converted into melatonin to help initiate sleep.” Disruptions in serotonin can throw off this natural rhythm, he adds.
You’re likely already familiar with melatonin—how does it link up with serotonin?
“Melatonin is synthesized from serotonin in the pineal gland,” says Allen. “This transformation is crucial: without adequate serotonin, your body can’t produce optimal levels of melatonin.”
This biochemical pathway explains why serotonin imbalances—whether due to mood disorders, stress, or lifestyle—can lead to sleep disturbances, he notes.
Additionally, serotonin interacts with a range of neurotransmitters, including dopamine, norepinephrine, and GABA.
“It works in concert with these systems to regulate mood, alertness, and arousal,” says Allen. “For instance, serotonin can balance dopamine to prevent overstimulation, while enhancing GABA activity to promote relaxation and sleep readiness.”
Factors affecting serotonin levels and sleep
There are several things that can affect serotonin levels, and in turn, sleep. These include:
- Diet: Allen says foods rich in tryptophan (like turkey, eggs, nuts, and seeds) can support serotonin synthesis. Carbohydrates help tryptophan cross the blood-brain barrier.
- Exercise: According to Allen, regular physical activity increases serotonin levels, which can improve both mood and sleep quality.
- Sunlight: Exposure to natural light boosts serotonin, “especially in the morning, reinforcing circadian alignment,” says Allen.
- Stress: Chronic stress can actually deplete serotonin and disrupt sleep.
- GI issues: Since a large percentage of serotonin is produced in the gut, gastrointestinal issues can impact levels, says Allen.
How to improve serotonin levels and boost sleep
Allen shares his top strategies for regulating serotonin for sleep:
- Prioritize daily sunlight exposure, especially in the morning.
- Incorporate exercise—even a 30-minute brisk walk can help.
- Eat a balanced diet with serotonin foods for sleep, like tryptophan-rich foods and complex carbs.
- Practice stress-reducing techniques like mindfulness or meditation.
- Stick to a consistent sleep-wake schedule, which reinforces serotonin-melatonin pathways.
FAQs
How does serotonin affect sleep?
“Serotonin is deeply intertwined with sleep regulation,” says Allen. “It contributes to the onset of sleep by calming the brain and is a precursor to melatonin—the hormone that governs the sleep-wake cycle.” Higher serotonin levels are associated with deeper, more restful sleep, while low levels can contribute to insomnia or fragmented sleep patterns, he adds.
What drains serotonin?
Things that can deplete serotonin, and create a feedback loop of low mood and poor sleep, include chronic stress and anxiety, a lack of sleep, poor nutrition, a sedentary lifestyle, substance use that includes alcohol, nicotine, and certain medications, and social isolation, says Allen.
How do I tell if my serotonin levels are low?
Signs of low serotonin may include persistent sadness or irritability, difficulty sleeping or staying asleep, fatigue, poor appetite or cravings for carbs, anxiety or feelings of restlessness, and a reduced interest in activities once enjoyed, says Allen. “Low serotonin is often linked to mood disorders like depression, which frequently coexist with sleep disturbances,” he adds.
Is melatonin or serotonin better for sleep?
Melatonin directly influences the timing of sleep, while serotonin sets the stage for healthy sleep architecture and mood, says Allen. “You can think of serotonin as the builder and melatonin as the timekeeper,” he says. “Supplementing melatonin may help shift your internal clock, but supporting serotonin has broader benefits for emotional well-being and long-term sleep health. Ideally, both work in harmony.”
How does cortisol affect sleep? Next, learn about the connection between the stress hormone cortisol and sleep.
