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Head-to-head evidence comparison — which supplement is right for you?
L-Glutamine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
7 of 9 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
3 of 3 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Green Tea Extract and L-Glutamine have evidence — compare verdict strength side-by-side.
250-500mg EGCG (or 500-1000mg green tea extract)
With meals, Morning or pre-exercise
Standardized extract (45-50% EGCG)
5-10g
Post-workout, Before bed, Or split throughout day
L-Glutamine powder
Acute and 4-8 weeks
Acute
30-60 minutes
2-4 weeks
2-4 weeks
1-2 weeks
Green tea (Camellia sinensis) for the prevention of cancer
The Cochrane database of systematic reviews (2020) · Meta analysis · n=1795
For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence).
Impact of flavan-3-ols on blood pressure and endothelial function in diverse populations: a systematic review and meta-analysis of randomized controlled trials
European journal of preventive cardiology (2025) · Meta analysis · n=5205
Flavan-3-ol interventions included epicatechin, epigallocatechin-gallate, cocoa products, tea, grape extract, and apples delivering 586 mg (95% CI 510, 662) total flavan-3-ols.
The effects of green tea extract supplementation on body composition, obesity-related hormones and oxidative stress markers: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials
The British journal of nutrition (2024) · Meta analysis · n=3802
Pooled effect sizes indicated that BM, BFP, BMI and MDA significantly reduced following GTE supplementation.
A Phase 3 Trial of l-Glutamine in Sickle Cell Disease
The New England journal of medicine (2018) · Rct · n=230
A total of 230 patients (age range, 5 to 58 years; 53.9% female) were randomly assigned, in a 2:1 ratio, to receive l-glutamine (152 patients) or placebo (78 patients).
What Is the Role of Nutritional Supplements in Support of Total Hip Replacement and Total Knee Replacement Surgeries? A Systematic Review
Nutrients (2018) · Systematic review
Amino acid supplementation is reported to reduce muscle atrophy and accelerate return of functional mobility.
Evidence and gaps in clinical outcomes of novel pharmacologic therapies for sickle cell disease: A systematic literature review highlighting insights from clinical trials and real-world studies
Blood reviews (2025) · Systematic review · n=97
A pivotal phase III study of l-glutamine showed that patients treated with l-glutamine had a 25 % reduction in pain crises and 33 % fewer hospital days compared to placebo. l-glutamine was generally well tolerated with minimal side effects.
Based on meta-analysis showing 9.29 mg/dl LDL reduction with 107-856 mg/d EGCG. Optimal cardiovascular benefits observed at 400-500 mg/day. Take with food to reduce GI side effects.
Based on RCT showing reduced URTI incidence in combat athletes (n=21) and enhanced IgA levels. Limited sample size and specific population studied. Effect may be primarily in high-stress/training conditions.
AI-estimated from published studies. Interpret as directional guidance.
L-Glutamine has a higher evidence score (9/10 vs 9/10) and wins in 2 of 3 categories.
Both Green Tea Extract and L-Glutamine score equally (85) for reduce inflammation.
No known interactions between Green Tea Extract and L-Glutamine have been documented in our database. However, always consult a healthcare provider before combining supplements.