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Head-to-head evidence comparison — which supplement is right for you?
L. plantarum 299v vs L. reuteri DSM 17938: they're closely matched on evidence (5 vs 6/10); 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. plantarum 299v and L. reuteri DSM 17938 are closely matched across evidence, studies, and safety.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Shared outcomes (1)
Outcomes where both L. plantarum 299v and L. reuteri DSM 17938 have evidence — compare verdict strength side-by-side.
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)
1 x 10^8 CFU daily (5 drops) for infant colic — the dose used in every positive trial
any
Oil-suspension drops standardized to DSM 17938
Immediate, per meal
12-25 weeks
4 weeks
n/a
1-3 weeks
n/a
1-3 days
4 weeks
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)
Lactobacillus reuteri to Treat Infant Colic: A Meta-analysis.
Pediatrics (2018) · Meta analysis
Day-21 adjusted mean difference in cry/fuss time: -25.4 min/day (95% CI -47.3 to -3.5)
Treating infant colic with the probiotic Lactobacillus reuteri: double blind, placebo controlled randomised trial.
BMJ (2014) · Rct · n=167
Probiotic group cried/fussed 49 minutes MORE than placebo at 1 month (95% CI 8 to 90, P=0.02)
Probiotics to prevent infantile colic.
Cochrane Database Syst Rev (2019) · Meta analysis
No difference in new cases of colic: RR 0.46 (95% CI 0.18-1.19), low certainty
Both L. plantarum 299v and L. reuteri DSM 17938 are closely matched — the best choice depends on your specific health goals.
For improve digestion, L. reuteri DSM 17938 has a higher relevance score (55 vs 50).
No known interactions between L. plantarum 299v and L. reuteri DSM 17938 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.