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Published on: 3/2/2026
Glycine is a calming neurotransmitter that helps lower core body temperature and quiet neural activity, and small clinical studies suggest about 3 grams taken at bedtime can improve sleep quality without acting like a sedative.
There are several factors to consider. See below for medically approved next steps like CBT-I, screening for sleep apnea if you snore or feel excessively sleepy, optimizing sleep habits, addressing mental health, and reviewing medications, plus the red flags that mean you should seek urgent care.
If you can't sleep, you're not alone. Millions of adults struggle with falling asleep, staying asleep, or waking up feeling unrefreshed. While stress, screens, and late-night habits play a role, there's also a biological side to sleep that many people overlook.
One key player? Glycine.
Glycine is a simple amino acid that your body naturally produces. It may not get as much attention as melatonin, but research shows glycine plays an important role in calming the brain and supporting healthy sleep patterns.
Let's break down what glycine does, how it affects sleep, and what medically approved next steps you should consider.
Glycine is one of the smallest amino acids in the body. It helps:
Most importantly for sleep, glycine functions as an inhibitory neurotransmitter, meaning it helps quiet brain activity.
Think of it as one of the brain's natural "brakes."
Research suggests glycine may improve sleep in several ways:
To fall asleep, your body temperature naturally drops. Glycine has been shown in clinical studies to:
This temperature drop is one of the biological signals that it's time for sleep.
Glycine works with receptors in the brainstem and spinal cord to:
If your brain feels "wired but tired" at night, glycine may help counter that overstimulation.
Small clinical studies have shown that taking glycine before bed may:
Importantly, glycine does not act as a sedative. It doesn't "knock you out." Instead, it supports your body's natural sleep processes.
True glycine deficiency is rare. However, modern lifestyles may increase your need for it.
You may benefit from additional glycine support if you:
Glycine is also a major component of collagen. Many people consume far less collagen than previous generations did, which may reduce glycine intake.
Before turning to supplements, consider dietary sources.
Foods rich in glycine include:
A protein-diverse diet often provides adequate glycine for most healthy adults.
Clinical research has used glycine doses around 3 grams before bedtime.
Some potential benefits:
However, glycine is not a cure-all. If insomnia is driven by anxiety, sleep apnea, depression, chronic pain, or medical conditions, glycine alone will not fix the root cause.
Always speak to a doctor before starting supplements if you:
Occasional poor sleep is normal. But ongoing sleep problems can indicate a sleep disorder or underlying health issue.
Warning signs include:
These could signal:
If you're experiencing persistent symptoms and want to better understand what might be causing your sleep problems, Ubie's free AI-powered Sleep Disorder symptom checker can help you identify potential causes and determine whether it's time to consult with a healthcare professional.
This personalized assessment takes just a few minutes and can guide your next steps.
If glycine alone isn't solving the problem, here are evidence-based steps that doctors commonly recommend:
This is considered the gold standard treatment for chronic insomnia. It helps:
CBT-I is more effective long term than sleeping pills.
If you snore loudly, feel exhausted during the day, or wake gasping, ask your doctor about a sleep study.
Untreated sleep apnea increases the risk of:
This is not something to ignore.
Anxiety and depression commonly disrupt sleep.
If racing thoughts keep you awake, consider:
Sleep and mental health are deeply connected.
Basic, but powerful:
Remember: glycine works best when paired with healthy sleep habits.
Some medications interfere with sleep, including:
If sleep worsened after starting a medication, talk to your doctor.
Let's be realistic.
Glycine may help if:
Glycine will not fix:
It's a supportive tool — not a medical replacement.
Do not delay medical care if you experience:
These could indicate serious or life-threatening conditions.
Always speak to a doctor about anything that feels severe, unusual, or progressively worsening.
If you can't sleep, your brain chemistry may be part of the story — and glycine plays a real role in calming neural activity and supporting natural sleep cycles.
Glycine:
But sleep problems are rarely caused by just one thing.
Use glycine as a supportive strategy — not a shortcut. Pair it with good sleep hygiene, stress management, and medical evaluation when needed.
And if you're unsure whether your sleep issues signal something more serious, consider starting with a free online Sleep Disorder symptom checker to guide your next step.
Good sleep is not a luxury. It's a foundation of long-term brain, heart, and metabolic health. If yours is struggling, take it seriously — and don't hesitate to speak to a qualified healthcare professional for personalized care.
(References)
* Inose H, Takeda N, Terashima M, et al. Effects of Glycine Ingestion on Human Sleep and Health: A Systematic Review. *Nutrients*. 2024 Jan 19;16(2):319. doi: 10.3390/nu16020319. PMID: 38257039.
* Yamadera W, Sato M, Suzuki H, et al. Glycine ingestion improves subjective sleep quality in individuals with insufficient sleep: A double-blind, randomized, placebo-controlled trial. *Sleep Biol Rhythms*. 2021;19(4):465-472. doi: 10.1007/s41105-021-00331-1. PMID: 34107567.
* Schutte-Rodin S, Manconi M, O'Brien J, et al. Clinical Practice Guideline for the Pharmacologic Treatment of Insomnia: An Update. *J Clin Sleep Med*. 2021 Jun 1;17(6):1127-1130. doi: 10.5664/jcsm.9324. PMID: 33998144.
* Kolla BP, Scharf SM. Cognitive Behavioral Therapy for Insomnia (CBT-I) in Adults: An Update for Clinicians. *Mayo Clin Proc*. 2020 Feb;95(2):331-344. doi: 10.1016/j.mayocp.2019.06.024. Epub 2019 Oct 11. PMID: 31607590.
* Mitchell MD, Johnson JA, Redeker NS. Non-Pharmacological Interventions for Insomnia. *Curr Treat Options Neurol*. 2018 Jan 20;20(1):3. doi: 10.1007/s11940-018-0487-y. PMID: 29352495.
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