Related Compounds
Compounds connected by the same goals, effects, or research topics.
Compound Profile
Glycine
Systematic review suggests sleep improvements in healthy populations with longer term glycine administration, but sleep studies were small and high risk of bias.
Use extra caution — May support subjective sleep quality; evidence is early and based on small trials. Details
Last reviewed: •4 sources citedReport a correctionProfile-wide ·B Moderate
Verdict: GlycineMaybe
Bottom line
An inexpensive, well-tolerated add-on with small trials suggesting better sleep quality and morning alertness. Subtle, not sedating.
- Evidence confidence
- Early — a few small but interesting sleep-quality trials
- Expected onset
- Same night to a few nights
- Give it
- 1–2 weeks
On the evidence: A handful of small trials on sleep quality; evidence base is limited.
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
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.
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
Safety & Cautions
May support subjective sleep quality; evidence is early and based on small trials. | Do not imply proven insomnia treatment or anti aging benefits.
High caution
Caution level: High. Multiple caution categories apply, or the record uses avoid/contraindication language.
- Liver-SensitiveLiver-related caution language appears in the profile.
- Stimulant-Like ProfileStimulant-like or activating caution language is present.
- Pregnancy/Breastfeeding CautionPregnancy or breastfeeding caution language is present.
Evidence-based safety
Caution when combined
Severity and certainty are shown separately. A high-priority caution can still be theoretical: these pairings are screened from shared contraindication mechanisms and are not automatically documented clinical interactions. Provenance identifies the source fields that produced each flag; it does not upgrade the certainty of the pairwise claim.
Moderate Caution
68 flagged pairingsSedation / CNS depression
Moderate Caution
68 flagged pairingsSedation / CNS depression
Representative pairings are shown below. Large mechanism groups are intentionally summarized to keep profiles focused and crawl-efficient.
Sedation / CNS depressionCertainty: Theoretical
Data provenance recorded for 68 of 68 pairings in this mechanism group.
- American Yellow Lotus — Theoretical interaction certainty
- Artemisia Absinthium — Theoretical interaction certainty
- Ashwagandha (Withania somnifera) — Theoretical interaction certainty
- Bacopa — Theoretical interaction certainty
- Black Seed — Theoretical interaction certainty
- Black Tea — Theoretical interaction certainty
- Blue Lotus — Theoretical interaction certainty
- Calamus — Theoretical interaction certainty
- Catuba — Theoretical interaction certainty
- Celastrus Paniculatus — Theoretical interaction certainty
- Chamomile — Theoretical interaction certainty
- Chinese Skullcap — Theoretical interaction certainty
+56 more pairings share this mechanism. Use the Safety Checker to review a specific combination.
Evidence Summary
Profile-wide ·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: Established research — main contexts: Glycine Receptor · NMDA Receptor · Glutathione System
Safety boundary: Safety note available — May support subjective sleep quality; evidence is early and based on small trials.
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 rating.
AdaptogenSleepStress & MoodLongevity
Citation density
1.3
Sources
4
Effects
3
Research recency
Mixed recency
Evidence Grade
Grade B: Moderate Evidence
Evaluation of methodological rigor, population reach, and evidence alignment.
- Design Match
- Systematic review
- Risk of Bias
- Low
- Consistency
- Consistent
Strongest recorded design is a systematic review, drawn from 3 recorded studies, 3 in people. No disagreement is recorded across them.
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.
- Strong
- Multiple RCTs, consistent direction, adequate effect size
- Moderate
- Some RCTs or consistent observational data in humans
- Preliminary / Mixed
- Animal or in-vitro only, or conflicting human data
- Traditional / Theoretical
- Traditional use only; no controlled human trials
Clinical Study Summaries (4)1 human evidence source · 0 human trials · Participant totals not consistently reported · Consistency not yet classifiable
Filter by study class
Showing 4 of 4 studies.
What the evidence actually shows
This table contains 4 structured sources, including 1 human evidence source; 0 are human trials.
| Study | Design | N | Dose | Duration | Population | Outcome | Result & magnitude | Source |
|---|---|---|---|---|---|---|---|---|
2023 Background | Systematic review Uses a predefined method to find and evaluate relevant studies, but may or may not pool their results statistically. | — | — | — | — | — | — | DOI → |
2007 Background | Other / unclear The study design is not yet classified clearly enough to infer its place in the evidence hierarchy. | — | — | — | — | — | — | DOI → |
2012 Background | Other / unclear The study design is not yet classified clearly enough to infer its place in the evidence hierarchy. | — | — | — | — | — | — | DOI → |
Subjective effects of glycine ingestion before bedtime on sleep quality 2006 Background | Other / unclear The study design is not yet classified clearly enough to infer its place in the evidence hierarchy. | — | — | — | — | — | — | 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
Dosing
- No standardized dose
- Human sleep studies often use gram level glycine, but exact dose should be tied to the specific cited trial. Avoid universal dosing if source row lacks dose. | Oral glycine powder/capsule; simple amino acid.
Mechanisms & biological pathways
Preclinical mechanism details from scientific profiles; these represent plausible pathways but do not guarantee clinical efficacy in humans.
- Neurotransmitter Modulation
- Neurotransmission Inhibition
- Glycine Receptor Modulation
- Neuroprotective Activity
- NMDA Receptor Co Agonism Modulation
- Oxidative Stress Modulation
Guides that use Glycine
Condition guides
Also in this cluster
Sleep & Recovery guide →Continue exploring
Related research paths
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Related Guides
Deeper context, comparisons, and practical research paths.
Related Articles
Deeper context, comparisons, and practical research paths.
Related Safety Pages
Safety checks and cautions relevant to this decision.
Compare & Sourcing
Compare side-by-side tradeoffs or verify active marker guidelines.
Related alternatives
Herbs for similar conditions
Tradeoffs
Free safety checklist
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Sourcing options
Glycine product picks
Recommendation status
Product recommendations are not shown for this profile because the current site safety and monetization policy does not permit them.
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.
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