Loading…
We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Head-to-head evidence comparison — which supplement is right for you?
L-Glutamine vs L. plantarum 299v: L-Glutamine has the stronger overall evidence (6 vs 5/10); they're alternatives for improve digestion — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
L-Glutamine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
3 of 3 studies with measurable effects showed benefit.
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Shared outcomes (1)
Outcomes where both L-Glutamine and L. plantarum 299v have evidence — compare verdict strength side-by-side.
5-10g
Post-workout, Before bed, Or split throughout day
L-Glutamine powder
1 x 10^9 CFU (1 billion) daily taken WITH the iron-containing meal is sufficient for the iron effect — in the dual-isotope crossover trial 10^9 was significant (28.6% vs 18.5%, p<0.028) while 10^10 was NOT (29.1% vs 20.1%, p=0.080). The freeze-dried capsule and IBS trials used 1 x 10^10 CFU daily, and the pregnancy trial used 1 x 10^10 CFU twice daily (2 x 10^10 CFU/day)
with-meals
Freeze-dried capsule standardized to 299v (DSM 9843)
Ongoing
2-4 weeks
2-4 weeks
Immediate, per meal
12-25 weeks
4 weeks
n/a
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.
A Systematic Review and Meta-Analysis on the Effects of Probiotic Species on Iron Absorption and Iron Status.
Nutrients (2019) · Meta analysis
Pooled SMD 0.55 (95% CI 0.22-0.88, p=0.001) for increased iron absorption across 8 studies
The effect of Lactiplantibacillus plantarum 299v together with a low dose of iron on iron status in healthy pregnant women: A randomized clinical trial.
Acta Obstet Gynecol Scand (2021) · Rct · n=326
Iron deficiency at week 35: 59% vs 78% (p=0.017); iron-deficiency anaemia 7.4% vs 21% (p=0.023)
Efficacy of Probiotics in Irritable Bowel Syndrome: Systematic Review and Meta-analysis.
Gastroenterology (2023) · Meta analysis
For global IBS symptoms, certainty of evidence was LOW for this strain (moderate only for Escherichia strains)
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 (6/10 vs 5/10) and wins in 2 of 3 categories.
For improve digestion, L-Glutamine has a higher relevance score (80 vs 50).
No known interactions between L-Glutamine and L. plantarum 299v have been documented in our database. However, always consult a healthcare provider before combining supplements.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.