Lactobacillus rhamnosus

Best for

Grow beneficial gut bacteria

Large effect, needs confirmation for 12 weeks · 1 study , n=99

4 papers · 4 claims · 6 outcomes scored · 3 positive

Outcomes

What lactobacillus rhamnosus actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Grow beneficial gut bacteria Large effect, needs confirmation

The species that produce vitamins and crowd out harmful bugs gain ground.

1 RCT n=99 15000000000 other 12 wk #1/14

40722352

large

1 RCT n=99

15000000000 other

12 wk

#1 /14

Reduce diarrhea and recover faster Likely modest benefit

Fewer loose stools, shorter episodes, and less fluid loss.

2 meta-analyses n=936 — 1 wk #6/17

17690340·35070839

small

2 meta-analyses n=936 Meta-analyzed I²=89%

—

1 wk

#6 /17

Ease stomach bug symptoms Faint early signal

Less vomiting, fever, and severity from acute gut infections.

1 RCT n=192 — 1 wk #2/2

17690340

small

1 RCT n=192

—

1 wk

#2 /2

Ease constipation and stay regular Not enough research

Softer stools, less straining, and more complete bowel movements.

1 RCT n=192 — 1 wk

17690340

—

1 RCT n=192

—

1 wk

—

Outcome	Effect	Evidence	Dose	Weeks	Rank
Grow beneficial gut bacteria Large effect, needs confirmation	large	1 RCT n=99	15000000000 other	12 wk	#1/14
Reduce diarrhea and recover faster Likely modest benefit	small	2 meta-analyses n=936 Meta-analyzed	—	1 wk	#6/17
Ease stomach bug symptoms Faint early signal	small	1 RCT n=192	—	1 wk	#2/2
Ease constipation and stay regular Not enough research		1 RCT n=192	—	1 wk	—

Risk profile

Adverse events and known drug interactions

Safety events

hepatic enzyme increased moderate

electrolyte imbalance mild

increased LDL cholesterol mild

blood glucose decreased mild

anaemia mild

Sources

Generated August 14, 2026

Lactobacillus rhamnosus

What lactobacillus rhamnosus actually does, by outcome

Adverse events and known drug interactions

More evidence for Lactobacillus rhamnosus

Bifidobacterium (unspecified)

Colostrum

Glutamine

Lactobacillus reuteri

Probiotics

Zinc

Lactobacillus rhamnosus

More evidence for Lactobacillus rhamnosus

NewBifidobacterium (unspecified)

NewColostrum

NewGlutamine

NewLactobacillus reuteri

NewProbiotics

NewZinc

Bifidobacterium (unspecified)

Colostrum

Glutamine

Lactobacillus reuteri

Probiotics

Zinc