Compound Profile
Glycine
Glycine may support subjective sleep quality and bedtime relaxation without being a strong sedative.
Last reviewed: •4 human studies cited
B ModerateMonograph visual
Glycine
The Hippie Scientist
Verdict: GlycineMaybe
Best for
- Improving perceived sleep quality
- Feeling less groggy the next morning
- A low-risk add-on
Not ideal for
- Severe insomnia alone
- A strong sedative effect
- Evidence confidence
- Early — a few small but interesting sleep-quality trials
- Expected onset
- Same night to a few nights
- Give it
- 1–2 weeks
Bottom line: An inexpensive, well-tolerated add-on with small trials suggesting better sleep quality and morning alertness. Subtle, not sedating.
On the evidence: A handful of small trials on sleep quality; evidence base is limited.
How strong is the evidence?Limited
Why not higher
- Only a few small trials, several from the same group
- Effects are subtle and subjective
Why not lower
- The small trials that exist point toward better sleep quality and morning alertness
- Very low risk and inexpensive
Practical takeaway: A cheap, low-risk add-on worth a short trial for sleep quality — not a stand-alone fix for significant insomnia.
Where to go next — guides & comparisons
Start here — new to this? Begin with Best supplements for sleep
Compare before choosing
- Sleep herbs vs. melatonin — if building a low-risk sleep stack
Continue reading
- If you want help sleeping → Sleep guides
- If you want help with anxiety or stress → Anxiety & stress guides
- If you want to browse more compounds → All compounds
Quick Stats
Evidence level
Moderate evidence
Typical onset
Varies by prep
Safety rating
Use extra caution: Use caution
Best for
Glycine Receptor, NMDA Receptor, Glutathione System
Avoid / review if
Severe Liver Or Kidney Disease Due To Reduced Amino Acid Clearance
Safety & Cautions
Review before use if any apply: Severe Liver Or Kidney Disease Due To Reduced Amino Acid Clearance.
Evidence-based safety
Caution when combined
These pairings share a flagged risk mechanism. They are additive-effect cautions derived from contraindication data, not confirmed clinical interactions. Consult a clinician before combining.
Moderate Caution
68 flagged pairingsSedation / CNS depression
Moderate Caution
68 flagged pairingsSedation / CNS depression
Browse the grouped cautions below. The list scrolls inside this card when long.
Sedation / CNS depression
- American Yellow Lotus
- Artemisia Absinthium
- Ashwagandha (Withania somnifera)
- Bacopa
- Black Seed
- Black Tea
- Blue Lotus
- Calamus
- Catuba
- Celastrus Paniculatus
- Chamomile
- Chinese Skullcap
- Coriandrum Sativum
- Corydalis
- Cymbopogon Citratus
- Damiana
- California Poppy
- Eucalyptus
- Gastrodia
- Gotu Kola (Centella asiatica)
- Hops
- Hypericum Perforatum
- Jatamansi
- Jujube
- Lavender
- Lavender
- Lavender Extract
- Lemon balm
- Lemon Balm Extract
- Lemon Verbena
- Lemongrass
- Lobelia Inflata
- Longan
- Magnolia
- Melatonin
- Lemon Balm
- Milk Oats
- Mugwort
- Muira Puama
- Myristica Fragrans
- Nicotiana Glauca
- Nicotiana Tabacum
- Oatstraw
- Ocimum Basilicum
- Parsley
- Passionflower
- Passionflower
- Passionflower Extract
- Passionflower Extract (Standardized)
- Kava
- Polygala
- Poria
- Raspberry Leaf
- Sage
- Schisandra Berry
- Schisandra Chinensis
- Scutellaria Baicalensis
- Skullcap
- Shankhpushpi
- Sophora Flavescens
- theanine
- Valeriana officinalis
- Valerian Extract (Standardized)
- Valerian Root Extract
- Valerian
- Verbena Officinalis
- Ashwagandha
- Wormwood
Evidence Summary
B ModerateEvidence lens
Useful signal, but study design, dose, and population still matter.
ModerateModerate evidence
Human clinical evidence: Present in source signals
Mechanistic / preclinical: Mechanism mapped — Neurotransmitter Modulation · Neurotransmission Inhibition · Glycine Receptor Modulation
Research maturity: More interpretable — main contexts: Glycine Receptor · NMDA Receptor · Glutathione System
Safety boundary: Safety note available — Review before use if any apply: Severe Liver Or Kidney Disease Due To Reduced Amino Acid Clearance.
This profile cites 4 human studies.
Evidence Strength
Confidence estimate based on the design quality and consistency of published clinical trials.
Glycine has a moderate evidence evidence rating.
AdaptogenSleepStress & MoodLongevity
Citation density
1.3
Sources
4
Effects
3
Research recency
Mixed recency
How evidence grades work
Each grade reflects the strength and consistency of published human evidence — not marketing claims. Grades are based on study count, design quality, effect size, consistency, and recency.
A
Strong
Multiple RCTs, consistent direction, adequate effect size
B
Moderate
Some RCTs or consistent observational data in humans
C
Preliminary / Mixed
Animal or in-vitro only, or conflicting human data
D
Traditional / Theoretical
Traditional use only; no controlled human trials
Clinical Study Summaries (4)Cited studies informing this profile. RCTs and reviews shown first.
| Study | Type | Sample | Source |
|---|---|---|---|
(2023) | Systematic review | — | DOI → |
(2007) | — | — | DOI → |
(2012) | — | — | DOI → |
Subjective effects of glycine ingestion before bedtime on sleep quality (2006) | — | — | DOI → |
How Glycine Works
Simplified mechanism pathway based on preclinical and pharmacological evidence. Does not confirm clinical efficacy.
Mechanism Pathway — How Glycine Works
CompoundTarget / ReceptorMechanismEffect / Outcome
Mechanisms & Biological Pathways▼
Preclinical mechanism details from scientific profiles; these represent plausible pathways but do not guarantee clinical efficacy in humans.
Neurotransmitter ModulationNeurotransmission InhibitionGlycine Receptor ModulationNeuroprotective ActivityNMDA Receptor Co Agonism ModulationOxidative Stress Modulation
Condition guides
Also in this cluster
Sleep & Recovery guide →Continue exploring
Related research paths
Compare & Sourcing
Compare side-by-side tradeoffs or verify active marker guidelines.
Review available sources for Glycine
Independent database mapping — evaluated separately from safety and efficacy scores.
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Related alternatives
Herbs for similar conditions
Tradeoffs
Free safety checklist
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Supplement stacking
Stack Glycine With
Commonly paired with Glycine. Review interactions and dosage before combining.
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Affiliate-ready sourcing
Glycine product picks
Affiliate recommendations for Glycine. Review safety, dose, and product quality before buying.
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Product Form & Quality Guidelines
When sourcing Glycine, verify the label for:
- Standardized Extract: Confirm active content percentages on the supplement facts panel (e.g. standardized to specific marker compounds) rather than simple raw herb weights.
- Third-Party Testing: Look for independent purity labels (USP, NSF, ConsumerLab, or Eurofins) to ensure the product is free from heavy metals, solvents, and contaminants.
- Form Bioavailability: Ensure the form matches evidence-supported configurations (e.g. chelated bisglycinate/glycinate for magnesium, micronized monohydrate for creatine) for optimal onset and digestion tolerance.
Safety first · Harm reduction
This information is educational and not medical advice. Start low, avoid risky combinations, and consult a licensed clinician before making health decisions—especially if you use medications, have diagnosed conditions, or are pregnant/breastfeeding.
Learn how we evaluate confidence, safety, and intensity on the methodology page.
Editorial Review
Checked against primary sources, cited evidence, and contraindication language before publication. Evidence claims, safety language, and affiliate modules are reviewed independently. Not personal medical advice.
Compound profile context
How to interpret Glycine
Glycine dosage by use case, onset and duration, safety limits, and interactions for glycine receptor, graded against research. Moderate Human Evidence… Use this compound profile to understand mechanism, evidence quality, and practical safety context before comparing products or building a stack. A biochemical pathway connection can be useful for discovery, but it is not the same as proven benefit in humans.
When reviewing Glycine, separate the active molecule from the product category around it. Dose form, absorption, extract standardization, medication interactions, and individual sensitivity can change the real-world risk-benefit picture.
For supplement planning, avoid combining multiple compounds with overlapping sedating, stimulating, serotonergic, blood-pressure, anticoagulant, or liver-metabolism effects unless a qualified clinician has reviewed the context.