What is the recommended dose of Glycine?

- **Sleep:** 3g, 30-60 min before bed - **Glutathione (GlyNAC):** 1.33mmol/kg/day (~100mg/kg) glycine + equivalent NAC - **General supplementation:** 3-5g/day - **Schizophrenia adjunct:** 0.4-0.8g/...

Is Glycine safe to take daily?

Glycine is rated "Use Caution" based on clinical evidence. - Virtually none at standard doses (3-5g) - Nausea at very high doses (>15g) - Mild drowsiness (mechanism of action for sleep benefit)

Does Glycine interact with any medications?

Glycine has 2 known drug interactions, including interactions with Clozapine, Antihypertensives. Check with your doctor before combining with prescription medications.

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Ingredient Research

Graded against 173,636 supplements + 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD

Glycine

MODERATE EVIDENCEAmino AcidLast updated April 2026

AVELOR SUMMARY

Glycine is a conditionally essential amino acid that serves as an inhibitory neurotransmitter, a key component of collagen synthesis, a precursor to glutathione (with NAC), and a metabolic substrate for creatine synthesis. Our research shows solid evidence for sleep quality improvement — 3g before bed reduces sleep latency and improves subjective sleep quality without next-day drowsiness. It's remarkably safe, dirt cheap, and synergistic with NAC for glutathione production (GlyNAC protocol).

EVIDENCE GRADES

Sleep quality (onset + satisfaction)Multiple positive RCTs (PMID: 22293292)

B+

Glutathione synthesis (with NAC)GlyNAC protocol strong in elderly (PMID: 33432175)

Schizophrenia (adjunct, high-dose)0.4-0.8g/kg/day as NMDA co-agonist

B-

Collagen synthesis supportConditional precursor

C+

Metabolic syndrome markersGlyNAC in elderly (PMID: 33432175)

C+

OPTIMAL DOSAGE

Sleep: 3g, 30-60 min before bed
Glutathione (GlyNAC): 1.33mmol/kg/day (~100mg/kg) glycine + equivalent NAC
General supplementation: 3-5g/day
Schizophrenia adjunct: 0.4-0.8g/kg/day (medical supervision required)
Dissolves easily in water; mildly sweet taste

Scan a supplement containing Glycine

DRUG INTERACTIONS

ClozapineModerate

Glycine may reduce clozapine effectiveness (opposing NMDA mechanisms)

AntihypertensivesMinor

Glycine has mild vasodilatory properties

SAFETY PROFILE

Drug Interactions

Side Effects

Virtually none at standard doses (3-5g)
Nausea at very high doses (>15g)
Mild drowsiness (mechanism of action for sleep benefit)

Pregnancy & Lactation

Glycine is a naturally occurring amino acid in protein foods. Supplemental doses (3-5g) considered safe. No adverse reports.

WADA Status

Not Prohibited

HOW AVELOR SCORES THIS

Combination with NAC (GlyNAC protocol): score synergy bonus for glutathione/aging applications

Combination with collagen: score synergy bonus (glycine is 33% of collagen's amino acid profile)

Sleep application at 3g: well-supported, cost-effective alternative to melatonin

Products in "sleep blends" with glycine <1g: flag as under-dosed (need 3g)

Clozapine interaction is the only clinically meaningful drug concern

CLINICAL REFERENCES

Bannai M et al. The effects of glycine on subjective daytime performance after sleep restriction.

PMID: 22293292

Kumar P et al. Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency.

PMID: 33432175

Kawai N et al. Sleep-promoting and hypothermic effects of glycine.

PMID: 16117182

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BCAAs / EAAs

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Independently graded against 173,636 indexed supplements with 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: April 2026

Not medical advice. Based on published clinical research and systematic reviews.

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