Glycine

Reviewed by the HeyPsych Medical Review Board

Board-certified psychiatrists and mental health professionals

Published August 17, 2025•Updated February 20, 2026•Reviewed February 20, 2026

Indications

Primary Indications

Improves sleep onset and qualitySupports neurotransmitter balanceProvides antioxidant and metabolic benefitsInvestigated as an adjunct in schizophrenia and OCD

Mechanism

Glycine acts as an inhibitory neurotransmitter in the spinal cord and brainstem while also functioning as a co-agonist at NMDA receptors in the brain, influencing excitatory glutamatergic signaling. By reducing core body temperature and modulating sleep-wake cycles, glycine can improve subjective and objective sleep quality. Its role in glutathione synthesis contributes to antioxidant defense and metabolic regulation.

Dosing

Adult Dosing

note: Lower doses (1–5 g) commonly used for sleep and relaxation.

typical: 3 g orally at bedtime for sleep; 10–60 g/day in divided doses studied in schizophrenia (clinical supervision required)

Dosage Forms

Powder
Capsules
Tablets

Onset Duration

Sleep benefits typically observed within days; psychiatric effects require weeks of sustained high-dose therapy in clinical trials.

Adverse Effects

Common Side Effects

• GI upset

• Soft stools

• Sedation

⚠️ Serious Side Effects

Electrolyte imbalance and renal strain at very high doses

Warnings

Critical Safety Information

→High-dose use (>30 g/day) should only be undertaken under medical supervision.
→May interact with antipsychotic treatment response.

Interactions

With: Clozapine or other antipsychotics

Risk: Potential modulation of efficacy

Action: Monitor clinical response

With: NMDA receptor antagonists (e.g., ketamine, memantine)

Risk: May alter drug effects

Action: Caution

Monitoring

Sleep quality
Cognitive status in psychiatric patients
Renal function in high-dose use

Special Populations

👶Pregnancy

Limited data; avoid unless prescribed

🤱Breastfeeding

Insufficient data; avoid unless supervised

👧Children & Adolescents (Under 18)

Not routinely recommended outside research

👴Older Adults (65+)

Generally safe at low doses; monitor renal function

Tapering

No taper required; may discontinue without withdrawal effects.

Clinical Notes

At bedtime doses (~3 g), glycine improves subjective sleep quality and next-day performance.
High-dose glycine has been trialed as an adjunct in schizophrenia, though results are mixed.
Acts as both inhibitory neurotransmitter and NMDA co-agonist, providing a dual role in CNS regulation.

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