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Head-to-head evidence comparison — which supplement is right for you?
Glycine vs Valerian Root: Glycine has the stronger overall evidence (6.5 vs 5.5/10); they're alternatives for perceived sleep quality — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Glycine wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Too few graded studies
1 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Too few graded studies
1 of 1 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Glycine and Valerian Root have evidence — compare verdict strength side-by-side.
3g before bed (no cited trial states the dose it used)
30-60 minutes before bed
Powder (dissolves easily, tastes sweet)
300-600mg extract
30-60 minutes before bed
Standardized extract capsules
and 1 more not shown
First few nights
Next morning
Immediate
2-4 weeks
2-4 weeks
Next morning
Immediate
The effect of glycine administration on the characteristics of physiological systems in human adults: A systematic review
GeroScience (2024) · Systematic review
The nervous system demonstrated the most positive effects, including improved psychiatric symptoms from longer-term glycine administration in psychiatric populations.
Glutamatergic drugs for schizophrenia
The Cochrane database of systematic reviews (2006) · Meta analysis · n=358
NMDA receptor co-agonists glycine and D-serine showed some effects in reducing the negative symptoms of schizophrenia (n=132, SMD -0.66, CI -1.0 to -0.3, p=0.0004), but the magnitude of the effect was moderate.
Ingestion of a Whey Plus Collagen Protein Blend Increases Myofibrillar and Muscle Connective Protein Synthesis Rates
Medicine and science in sports and exercise (2025) · Rct · n=28
In addition, myofibrillar protein synthesis rates were higher in BLEND compared with PLA in both the rested (0.038 ± 0.008 and 0.031 ± 0.006%·h -1 , respectively; P < 0.05) and exercised (0.052 ± 0.011 and 0.039 ± 0.009%·h -1 , respectively; P < 0.01) leg.
Valerian Root in Treating Sleep Problems and Associated Disorders-A Systematic Review and Meta-Analysis
Journal of evidence-based integrative medicine (2020) · Meta analysis · n=6894
In addition, therapeutic benefits could be optimized when it was combined with appropriate herbal partners.
Fixed herbal drug combination with and without butterbur (Ze 185) for the treatment of patients with somatoform disorders: randomized, placebo-controlled pharmaco-clinical trial
Phytotherapy research : PTR (2009) · Rct · n=182
Analysis of the ITT population confirmed these results.
Herbal Medicines in Autism Spectrum Disorder: Therapeutic Potential, Plant Components, and Dosage Guidelines
Alternative therapies in health and medicine (2025) · Review
Passionflower and Valerian Root alleviate anxiety and hyperactivity through GABAergic pathways.
The two points come from two separate placebo-controlled trials, not from one trial comparing doses. 400 mg of aqueous root extract, taken on separate test nights, shortened self-rated sleep latency and improved sleep quality in 128 people, most clearly in poor or irregular sleepers (PMID 7122669). 530 mg of root extract nightly for 30 nights improved Pittsburgh sleep quality scores after heart bypass surgery in 72 patients, with no change in prothrombin time (PMID 33420602). The extracts and populations differ, so the curve is drawn flat and cannot show whether 530 mg does more than 400 mg. The cited meta-analyses found subjective improvement but give no per-trial doses (PMID 17145239, 33086877). No higher nightly dose for sleep was tested in a cited trial.
AI-estimated from published studies. Interpret as directional guidance.
Glycine has a higher evidence score (6.5/10 vs 5.5/10) and wins in 3 of 3 categories.
For perceived sleep quality, Glycine has a higher relevance score (95 vs 75).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
Ashwagandha, L-theanine, magnesium, saffron — what actually helps stress, and the safety caveats.
When to take what, with or without food, and which supplements compete vs pair well.
Melatonin, magnesium, glycine, L-theanine — tiered by evidence, plus a wind-down timeline.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.