Bifidobacterium infantis 35624: Evidence, Trial Doses & Interactions

About Bifidobacterium infantis 35624

A single strain isolated from human intestinal mucosa and studied mainly in irritable bowel syndrome. It was originally classified as B. infantis and has since been reclassified as B. longum subsp. longum.

The 35624 strain produced one of the more carefully designed probiotic trials of its era: a dose-ranging study in women with irritable bowel syndrome in which the middle dose of 100 million CFU improved a composite symptom score while the higher dose did not, an inverted dose-response the authors attributed to formulation problems at the top dose. The trial was conducted by the company that went on to sell the strain. Later trials and reviews have been less impressive, and the reclassification of the organism means the name it was famous under is no longer taxonomically correct.

Sold as

Capsule

Standardised to

CFU of strain 35624, commonly 1 billion in retail product against 100 million in the pivotal trial — a product without this marker may not resemble what was studied.

Also known as

B. infantis 35624, Bifantis, 35624 strain

Regulation: Sold as a dietary supplement with no pre-market efficacy review. EFSA did not authorise health claims for this strain in the EU. Retail dose and trial dose are not the same, which is unusual enough to be worth checking on the label.

What the research used

The amounts, forms and durations published trials of Bifidobacterium infantis 35624 actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

Studied for Irritable bowel syndrome
100 million CFU
Moderate
Capsule, once daily · 4 weeks
The dose that outperformed placebo in the pivotal trial. A ten-fold higher dose in the same trial did not, which the investigators attributed to a formulation problem — an odd result that has not been resolved by later work.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

Any time
Not enough
Taken once daily without reference to meals in the trials. No timing comparison has been published for this strain.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

Digestive comfort

Gut & Digestive Health

Moderate evidence

A randomised dose-ranging trial reported improvement in a composite irritable bowel symptom score at 100 million CFU/day over four weeks, and some later reviews include it among the strains with reasonable IBS evidence. The pivotal work was manufacturer-conducted and the odd dose-response has not been explained.

What may be going on: The strain has been reported to modify cytokine ratios and to influence regulatory T-cell responses in humans, though the link from that to symptom change is not established.

Moderate evidence. Several human studies point the same way, with real caveats.

View the 4 sources

Multi-Center, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group Study to Evaluate the Benefit of the Probiotic Bifidobacterium infantis 35624 in Non-Patients With Symptoms of Abdominal Discomfort and Bloating.(opens in a new tab)
Randomised controlled trial · The American journal of gastroenterology · 2017 · PMID 27845337
Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles.(opens in a new tab)
Randomised controlled trial · Gastroenterology · 2005 · PMID 15765388
Efficacy of Bifidobacterium infantis 35624 in patients with irritable bowel syndrome: a meta-analysis.(opens in a new tab)
Meta-analysis · Current medical research and opinion · 2017 · PMID 28166427
Efficacy of an encapsulated probiotic Bifidobacterium infantis 35624 in women with irritable bowel syndrome.(opens in a new tab)
Randomised controlled trial · The American journal of gastroenterology · 2006 · PMID 16863564

Deep research mode adds each paper’s own conclusion and stated limitations.

Inflammatory markers

Inflammation

Limited evidence

Small studies report reduced circulating C-reactive protein and changes in cytokine profile with this strain in several conditions. The findings are preliminary and their relationship to symptoms is unclear.

Limited evidence. Early human work, or mostly lab and animal research.

View the 3 sources

Bifidobacterium infantis 35624 modulates host inflammatory processes beyond the gut.(opens in a new tab)
Randomised controlled trial · Gut microbes · 2013 · PMID 23842110
Bifidobacterium infantis 35624 administration induces Foxp3 T regulatory cells in human peripheral blood: potential role for myeloid and plasmacytoid dendritic cells.(opens in a new tab)
Randomised controlled trial · Gut · 2012 · PMID 22052061
Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles.(opens in a new tab)
Randomised controlled trial · Gastroenterology · 2005 · PMID 15765388

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

Avoid
Immunocompromise, central lines and critical illness
The standard live-culture contraindications apply. Severely immunosuppressed, critically ill and central-line patients should not start probiotics without specialist advice.
Worth knowing
Retail dose differs from the trial dose
The effective dose in the pivotal trial was 100 million CFU/day, and the higher dose tested alongside it did not work. Retail products commonly supply a billion, which is neither the dose that succeeded nor the one that failed.
Worth knowing
Manufacturer-conducted pivotal evidence
The trials that established this strain were run by its commercial owner, and independent replication is limited. Later systematic reviews of probiotics in irritable bowel syndrome describe the overall evidence as low quality.

Bifidobacterium infantis 35624

What bifidobacterium infantis 35624 may help with

About Bifidobacterium infantis 35624

What the research used

When it was taken

Any time

The evidence in depth

Digestive comfort

Inflammatory markers

Things to know

Immunocompromise, central lines and critical illness

Retail dose differs from the trial dose

Manufacturer-conducted pivotal evidence

What bifidobacterium infantis 35624 may help with

About Bifidobacterium infantis 35624

What the research used

When it was taken

🕐Any time

The evidence in depth

Digestive comfort

Inflammatory markers

Things to know

Immunocompromise, central lines and critical illness

Retail dose differs from the trial dose

Manufacturer-conducted pivotal evidence

Any time