Ingredient Dossier · Xtra-Brain® · nutropx.com/science

9 Probiotic Strains + FOS

A Multi-Strain Probiotic Blend Designed for the Gut-Brain Axis

Xtra-Brain® combines nine probiotic strains from CHR Hansen’s UAS Laboratories portfolio with fructooligosaccharides (FOS) prebiotic fiber. The product is built around the gut-brain axis — the bidirectional communication network between the gut microbiota and the central nervous system — with the primary structure-function role of supporting digestive health and a healthy gut microbiome in healthy adults.

9 UA-trademarked strains 50 billion CFU per capsule + FOS prebiotic EFSA QPS species Manufactured by DaVinci Laboratories

UAS Laboratoriesnow part of Chr. Hansen A/S (2020)

UA-trademarked strains 9-strain blend Plus FOS prebiotic DaVinci stabilization technology

Strains

UA-trademarked · Chr. Hansen / UAS Labs

CFU per capsule

50B

52.5 billion at manufacture

Prebiotic

FOS

Fructooligosaccharides

Capsule weight

246 mg

Stabilized nondairy probiotic complex

What is it?

Xtra-Brain® is a multi-strain probiotic supplement built on DaVinci Laboratories’ stabilized nondairy probiotic complex. Each capsule delivers nine specific probiotic strains from CHR Hansen’s UAS Laboratories portfolio, totaling 52.5 billion colony-forming units (CFU) at manufacture with a guarantee of 50 billion CFU per capsule, plus NutraFlora® fructooligosaccharides (FOS) — the branded prebiotic fiber from Ingredion.

The product is positioned around the gut-brain axis — the bidirectional communication network between the gut microbiota and the brain that operates through the vagus nerve, microbial metabolite production, immune signaling, and HPA-axis modulation. The primary structure-function role of Xtra-Brain® is supporting digestive health and a healthy gut microbiome in healthy adults; the gut-brain-axis framing reflects the broader scientific concept that gut microbial health is connected to overall wellness, including cognitive and emotional wellness.

An important transparency point about probiotic research: Probiotic effects are strain-specific — findings for one probiotic strain do not automatically transfer to a different strain of the same species. The published gut-brain axis research most commonly cites other strains (such as B. longum 1714, L. helveticus R0052 + B. longum R0175, or L. rhamnosus JB-1), not the exact UA strains in Xtra-Brain®. We describe Xtra-Brain®’s evidence at two levels on this page: strain-matched evidence (research that used the exact UA strains in the product, which exists only for digestive endpoints) and gut-brain axis concept evidence (research on other probiotic strains that establishes the broader gut-brain mechanism). Both are valuable; neither should be conflated with the other.

The 9 strains

All nine strains carry the “UA” trademark and originate from UAS Laboratories LLC, acquired by CHR Hansen A/S in 2020. Strain identifiers below reflect both the familiar Lactobacillus nomenclature and the updated 2020 Zheng et al. taxonomic reclassification.

Composition per 1 capsule serving

Lactobacillus acidophilus(remains L. acidophilus post-2020)

UALa-01

Foundational lactobacillus · Gut barrier function research

Lactiplantibacillus plantarum(formerly L. plantarum)

UALp-05

Widely studied for digestive endpoints

Lacticaseibacillus casei(formerly L. casei)

UALc-03

Gut microbiome diversity support

Ligilactobacillus salivarius(formerly L. salivarius)

UALs-07

Found naturally in saliva and gut

Lacticaseibacillus rhamnosus(formerly L. rhamnosus)

UALrh-18

Well-characterized digestive probiotic species

Streptococcus thermophilus(unchanged)

UASt-09

In-vitro evidence for goblet-cell / mucosal barrier gene support (cell-culture)

Bifidobacterium breve(unchanged)

UABb-11

Bifidobacterium foundational species

Bifidobacterium bifidum(unchanged)

UABb-10

Studied in Martoni 2019 for digestive regularity

Bifidobacterium longum(unchanged)

UABl-14

Studied in Martoni 2019 for digestive regularity

FructooligosaccharidesNutraFlora® FOS prebiotic fiber

Prebiotic

Selectively feeds Bifidobacteria (bifidogenic effect)

About the 2020 Lactobacillus reclassification: In 2020, the original 261-species Lactobacillus genus was reclassified into 25 genera based on phylogenetic and genomic analysis (Zheng et al., Int J Syst Evol Microbiol). The familiar names (L. plantarum, L. casei, etc.) remain in widespread industry use and on product labels, but the current scientific names are now Lactiplantibacillus, Lacticaseibacillus, Ligilactobacillus, and others. We include both names for transparency and scientific accuracy.

The gut-brain axis

The microbiota-gut-brain axis is the bidirectional communication network between the gut microbes and the central nervous system, characterized in depth by Cryan, Dinan, and colleagues (Physiological Reviews 2019, “The Microbiota-Gut-Brain Axis”). The relevant pathways are well-described in the scientific literature, though the clinical translation to specific cognitive or mood outcomes in healthy adults remains an area of active research.

Bidirectional communication pathways

Gut microbiota

Probiotic strains + prebiotic FOS support a diverse gut microbiome

Microbial metabolites

SCFAs (acetate, propionate, butyrate), neurotransmitter precursors

Vagus nerve & immune signaling

Gut→brain signals via vagal afferents and systemic mediators

CNS effects

HPA-axis, mood, cognitive function pathways

Professor 5-Brain explains

Here’s what makes the gut-brain axis so interesting. Your gut microbes produce or influence many of the same neurotransmitters your brain uses — serotonin precursors, GABA, even short-chain fatty acids that signal up the vagus nerve. About 90–95% of your body’s serotonin is actually made in the gut, by enterochromaffin cells. The honest part: this is real, well-characterized biology, but translating it into “take this probiotic and feel calmer” in healthy adults is much harder than the marketing usually admits. The 2020 Marx meta-analysis pooled 22 RCTs and found no significant cognitive effect overall. That’s why Xtra-Brain’s honest positioning is digestive health first, gut-brain axis education second, and any wellness narrative held loosely.

Vagus nerve signaling

The vagus nerve is a major conduit for gut→brain signaling. The landmark animal mechanism study (Bravo et al. 2011) demonstrated that L. rhamnosus JB-1 altered central GABA receptor expression and stress responses in mice, with effects abolished by vagotomy. Animal evidence; the strain used (JB-1) is not in Xtra-Brain.

Established mechanism · Animal evidence with different strain

Microbial neurotransmitter precursors

Gut bacteria including Lactobacillus and Bifidobacterium can produce or modulate GABA and influence serotonin synthesis. Enterochromaffin cells in the GI mucosa produce 90–95% of total body serotonin (Martin et al. 2017). General mechanism well-characterized at the species level.

Established at the species level

Short-chain fatty acids (SCFAs)

Fermentation of fibers, including FOS, by gut bacteria yields acetate, propionate, and butyrate. SCFAs support the intestinal barrier, influence enteroendocrine and immune signaling, and act through free-fatty-acid receptors (GPR41/43). The mechanistic link between prebiotic fiber, gut microbes, and gut-brain signaling.

Well-established gut biochemistry

HPA axis & cortisol

Several probiotic strains and prebiotics have been studied for associations with the hypothalamic-pituitary-adrenal stress response. Allen 2016 reported attenuated cortisol output with B. longum 1714; Schmidt 2015 reported reduced cortisol awakening response with B-GOS prebiotic. Different strains and prebiotic forms than Xtra-Brain.

Studied in other strains/prebiotics

Gut barrier integrity

Probiotics can support epithelial barrier integrity. In-vitro research using human colonic epithelial cells (UASt-09) showed associations with goblet-cell and mucosal-barrier gene expression (MUC2 and related markers). Cell-culture evidence only — not yet established in human clinical studies.

Cell-culture evidence for one UA strain

FOS as prebiotic fiber

FOS selectively feeds Bifidobacteria (the bifidogenic effect), increasing SCFA production and supporting bifidobacterial populations within the gut microbiome. This is the established prebiotic mechanism of FOS. Important: in Schmidt 2015, the FOS arm did not produce the cortisol or attentional-bias effects that the B-GOS arm produced — we do not attribute stress or mood effects to FOS specifically.

Bifidogenic effect established · Stress/mood effects not demonstrated for FOS

Who Xtra-Brain® is for

Xtra-Brain® is designed as a broad-spectrum daily probiotic with a gut-brain axis framing, distinct from the 5-Brain® multi-ingredient cognitive formula and from Xynaptic Drops™ (citicoline). It serves several use cases:

Daily digestive support

A multi-strain probiotic plus FOS prebiotic for healthy adults who want to support digestive health and a healthy gut microbiome through daily probiotic supplementation.

Gut-brain wellness layer

For those who want to engage with the gut-brain axis concept — supporting the gut microbiome as part of an overall wellness approach that includes cognitive and emotional wellbeing.

Complementary to 5-Brain® / Xynaptic

Operates on a fundamentally different mechanism than the cognitive supplements: where 5-Brain® supports neuronal mechanisms directly, Xtra-Brain® supports the gut microbiome and the gut-brain communication pathway.

Daily, consistent use

Probiotic effects depend on consistent daily use to maintain gut microbiome populations. Most published trials use durations of 4–12 weeks. Plan for daily use to maintain the supportive effects.

Research evidence

The studies below are organized into two categories: strain-matched evidence (research that used the exact UA strains in Xtra-Brain®) and gut-brain axis concept evidence (research on other probiotic strains that establishes the broader gut-brain mechanism). Each study identifies the exact strain and form tested.

Strain-matched evidence

Uses exact UABl-14 + UABb-10 strainsRCT · Digestive endpoint

Martoni et al. (2019) — J Dig Dis

n=94 adults 18–65 · Multi-strain blend (L. acidophilus DDS-1, B. animalis subsp. lactis UABla-12, B. longum UABl-14, B. bifidum UABb-10) · 1.5×10⁹ CFU/day · 4 weeks

The only published RCT using exact Xtra-Brain® strains (B. longum UABl-14 and B. bifidum UABb-10). The probiotic group showed statistically significant within-group improvement on PAC-SYM digestive symptom measures (p<0.001), though the primary endpoint between-group difference was not significant. The probiotic group also showed faster normalization of stool frequency and consistency (most normalized within ~1 week). Endpoint: digestive/regularity. No brain or cognitive measures. Population: adults with functional bowel concerns.

PMID 31271261 Exact UA strains: UABl-14 + UABb-10 · Digestive endpoint only

Key takeawayThe strain-matched anchor study. Martoni 2019 tested two of Xtra-Brain®’s exact UA strains (B. longum UABl-14 + B. bifidum UABb-10) at 10 billion CFU each in IBS patients over 6 weeks, with significant within-group improvement on digestive symptoms. The only published trial using any of Xtra-Brain®’s exact strains. Population was IBS, not healthy adults.

In-vitro cell culture only

UASt-09 cell-culture barrier study (2020) — Microorganisms

In-vitro study in human colonic epithelial cells · UASt-09 strain (S. thermophilus)

Cell-culture research using human colonic epithelial cells reported that UASt-09 upregulated goblet-cell and mucosal-barrier gene expression including MUC2. In-vitro/cell-culture evidence only — not yet established in human clinical trials. Supports a cautious gut-barrier-mechanism narrative for one of the Xtra-Brain® strains; does not support human outcome claims.

PMID 33182355 Cell-culture only · One UA strain (UASt-09)

Key takeawayCell-culture barrier study using UASt-09 (one of Xtra-Brain®’s exact strains). Demonstrated that UASt-09 supports intestinal barrier function in vitro. Mechanism-supportive but not a human clinical trial; cannot support outcome claims.

Gut-brain axis concept evidence (different strains)

RCT · Different strainL. helveticus not in Xtra-Brain

Messaoudi et al. (2011) — British Journal of Nutrition

n=55 healthy adults · L. helveticus R0052 + B. longum R0175 · ~3×10⁹ CFU/day · 30 days

Researchers reported the probiotic formulation was associated with reductions in global psychological distress measures, HADS scores, and urinary free cortisol vs placebo. Different strains than Xtra-Brain®: Xtra-Brain® contains B. longum UABl-14 (different B. longum strain) and does not contain L. helveticus at all. Provides general gut-brain axis rationale that specific probiotic formulations can support stress and mood-related measures in healthy adults; does not support Xtra-Brain®-specific claims.

PMID 20974015 Strain mismatch + species mismatch (no L. helveticus in Xtra-Brain®)

Key takeawayMessaoudi 2011 used L. helveticus R0052 + B. longum R0175 — different strains than any in Xtra-Brain®. Reported associations with psychological distress measures in healthy adults. Cited for the gut-brain axis concept; we do not transfer findings to Xtra-Brain®’s strains.

RCT · Different strainB. longum strain 1714

Allen et al. (2016) — Translational Psychiatry

n=22 healthy male volunteers · B. longum 1714 · 1×10⁹ CFU/day · 4 weeks per condition

Researchers reported associations with attenuated cortisol output and subjective anxiety responses during a socially evaluated cold pressor test, reduced daily reported stress, subtle associations with hippocampus-dependent visuospatial memory, and enhanced frontal-midline EEG mobility. Different B. longum strain than Xtra-Brain®: Xtra-Brain® contains B. longum UABl-14, not B. longum 1714. Small all-male sample.

PMID 27801892 Same species, different strain · All male

Key takeawayAllen 2016 used B. longum 1714 — a different B. longum strain than Xtra-Brain®’s UABl-14. Reported associations with cortisol awakening response. Strain specificity is critical: 1714 results do not transfer to UABl-14.

RCT + fMRI · Different strains

Tillisch et al. (2013) — Gastroenterology

n=36 healthy women (FMPP n=12) · Fermented milk product (B. animalis subsp. lactis, S. thermophilus, L. bulgaricus, Lactococcus lactis) · Twice daily · 4 weeks

Researchers reported the fermented milk product was associated with altered activity of brain regions controlling central processing of emotion and sensation during an emotional faces task (p=0.004) and changed midbrain and resting connectivity. Authors emphasize this is proof-of-concept — effects were observed but not characterized as “beneficial.” Different strains and product format (fermented milk, not capsule) than Xtra-Brain®. Industry-funded (Danone Research).

PMID 23474283 Strain + format mismatch · fMRI imaging study

Key takeawayTillisch 2013 used a Danone multi-strain fermented milk product — none of these strains are in Xtra-Brain®. Reported associations with brain activity patterns via fMRI. Concept-level evidence for the gut-brain axis; not Xtra-Brain® specific.

RCT · Different multi-strain blendClosest species-level analog

Steenbergen et al. (2015) — Brain, Behavior, and Immunity

n=40 healthy adults without current mood disorder · Multispecies probiotic (B. bifidum W23, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, Lactococcus lactis W19+W58) · 4 weeks

Researchers reported the multispecies probiotic was associated with reduced overall cognitive reactivity to sad mood vs placebo, primarily via associations with reduced rumination and aggressive thoughts. Species overlap with Xtra-Brain® is high (L. acidophilus, L. casei, L. salivarius, B. bifidum present in both products) — but the exact W-series strains differ from the UA strains. Closest species-level analog among the gut-brain axis healthy-population studies.

PMID 25862297 Species overlap, strain mismatch · Healthy adults

Key takeawaySteenbergen 2015 used a multispecies probiotic blend (Winclove Ecologic 825) — different strain identifiers than Xtra-Brain®. Reported associations with cognitive reactivity to sad mood. Cited for gut-brain axis support; not strain-matched.

FOS arm null — honest disclosureRCT · Tested FOS specifically

Schmidt et al. (2015) — Psychopharmacology

n=45 healthy adult volunteers · FOS, B-GOS, or placebo · Daily · 3 weeks

The single most relevant prebiotic study for Xtra-Brain®’s FOS component. Researchers reported that B-GOS (Bimuno-galactooligosaccharides) was associated with reduced salivary cortisol awakening response and decreased attentional vigilance to negative stimuli. Critically, the FOS arm showed no significant effects on these endpoints. We disclose this directly because it is the most honest available evidence about FOS as a prebiotic in the gut-brain context: FOS supports the bifidogenic prebiotic mechanism (well-established) but did not produce stress or mood effects in this specific trial. We do not attribute stress or mood effects to the FOS component of Xtra-Brain®.

PMID 25449699 FOS arm was null · Positive effects were B-GOS · Direct honest disclosure

Key takeawaySchmidt 2015 prebiotic study — the FOS arm produced null findings on cortisol and attentional-bias endpoints (only B-GOS was active). We disclose this directly because Xtra-Brain® contains FOS. We do not attribute stress or mood effects to the FOS component — the prebiotic mechanism we support is bifidogenic, not stress-modulating.

Meta-analysis null — counterweight22 RCTs · n=1,551

Marx et al. (2020) — Neuroscience & Biobehavioral Reviews

Systematic review and meta-analysis of 22 RCTs · n=1,551 (probiotics 11 studies/n=724; prebiotics 5/n=355; fermented foods 6/n=472) · Mixed healthy and clinical populations

The most rigorous meta-analytic synthesis of pre/probiotics and cognition to date. Researchers reported that no intervention had a statistically significant effect on global or domain-specific cognition. Authors concluded it is “too early to recommend” pre/probiotics for cognitive outcomes; benefits where seen were in specific strains or populations such as older or cognitively impaired adults. High heterogeneity across studies. This is the key counterweight showing the overall published evidence for probiotic-based cognitive enhancement in mixed populations is not yet established at the meta-analytic level.

PMID 32860802 Pooled 22 RCTs · No significant cognitive effect overall

Key takeawayMarx 2020 meta-analysis (n=1,551 across multiple trials) found no significant cognitive effect of pre/probiotics overall in cognitively healthy adults. The most honest counterweight in the pre/probiotic cognition literature. Reinforces that strain-specific evidence matters more than category-level claims.

RCT · Different strain

Benton et al. (2007) — European Journal of Clinical Nutrition

n=124 community adults (mean age ~62) · Probiotic milk drink (L. casei Shirota) · Daily · 3 weeks

Researchers reported no overall mood change with probiotic milk drink consumption; participants with the poorest baseline mood showed associations with mood measures. Self-reported less-frequent constipation correlated with better baseline mood and mental clarity. Largely null on cognitive measures. Different strain (L. casei Shirota) than Xtra-Brain® (L. casei UALc-03). Provides honest balance — probiotic effects on mood in already-healthy adults are subtle and may be limited to those with lower baseline mood.

PMID 17151594 L. casei Shirota · Largely null on mood/cognition in general sample

Key takeawayBenton 2007 used a probiotic yogurt — different strains than Xtra-Brain®. Reported mood-related associations in adults with subclinical low mood at baseline. Cited as additional gut-brain axis concept evidence; not strain-matched to our product.

What the research actually says

Honest evidence summary

Xtra-Brain® is the most evidence-nuanced product in the Nutropx lineup and warrants the most careful framing. The central honest point: probiotic effects are strain-specific, and Xtra-Brain®’s exact UA strains have limited published clinical literature for cognitive, mood, or stress outcomes — even though the gut-brain axis as a biological concept has substantial scientific support.

What studies consistently support

Martoni 2019 tested two of Xtra-Brain®’s exact UA strains (B. longum UABl-14 + B. bifidum UABb-10) in IBS patients at 10 billion CFU each over 6 weeks, with significant within-group improvement on digestive symptom measures — the strain-matched anchor study for digestive applications.
The gut-brain axis as a biological concept is real, well-characterized, and the subject of extensive research (Cryan & Dinan 2019; multiple human RCTs).
FOS is an established prebiotic that selectively feeds Bifidobacteria (the bifidogenic effect — well-established at the mechanism level).
Probiotic strains in the EFSA QPS list have a long history of safe use; UA-trademarked strains from CHR Hansen / UAS Laboratories have appropriate safety qualifications.
UASt-09 cell-culture work supports intestinal barrier function in vitro (mechanism evidence; not human outcome data).

What remains uncertain

No published human clinical trial has tested any of Xtra-Brain®’s exact UA strains for cognitive, mood, or stress outcomes. This is the central honesty point for any gut-brain claims.
The published gut-brain axis research uses different strains (B. longum 1714, L. helveticus R0052 + B. longum R0175, L. rhamnosus JB-1, multispecies W-series blends) — and probiotic effects are strain-specific. Findings on one strain do not automatically transfer to another, even of the same species.
In Schmidt 2015, the FOS arm produced no cortisol or attentional-bias effects (only B-GOS was active). We do not attribute stress or mood effects to the FOS in Xtra-Brain®.
The Marx 2020 meta-analysis (n=1,551) found no significant cognitive effect of pre/probiotics overall in cognitively healthy adults.

What to realistically expect

Xtra-Brain®’s primary structure-function role is supporting digestive health and a healthy gut microbiome — not cognitive or mood enhancement.
Allow 2–4 weeks of consistent daily use before evaluating effects. Probiotic effects accumulate over time as the gut microbiome adjusts.
The gut-brain axis framing reflects the scientific concept that gut microbial health is connected to overall wellness — an active and credible area of research, but not yet a basis for specific cognitive or mood-effect claims for healthy adults at our strains.
Mild transient gas or bloating in the first few days is normal and typically resolves as the gut microbiome adjusts.

Professor 5-Brain — the honest take

Here’s the line we won’t cross: most probiotic brands cite a famous gut-brain study using one strain, then sell you a totally different strain — and they let you connect dots that don’t actually connect. Probiotic effects are strain-specific. The B. longum 1714 in the famous Allen 2016 cortisol study is not the UABl-14 in Xtra-Brain®. The L. helveticus R0052 in the Messaoudi distress study is not in our blend at all. So here’s our position: Xtra-Brain® is a well-formulated daily probiotic for digestive health and gut microbiome support, with the gut-brain axis as the scientific concept context, not as a cognitive or mood claim. When the strain-matched cognitive evidence appears, we’ll update this page. Until then, we’re telling you exactly what we know — and what we don’t.

Why we selected this blend

Formulation rationale

Broad-spectrum, multi-strain design. The 9 UA strains span five Lactobacillus genera (post-2020 reclassification: Lactobacillus, Lactiplantibacillus, Lacticaseibacillus, Ligilactobacillus), one Streptococcus, and three Bifidobacterium species — covering the major probiotic taxa with well-characterized safety histories. This broad-spectrum design matches the most credible analog among healthy-population gut-brain studies (Steenbergen 2015 multispecies blend).

Two strains with direct digestive RCT evidence. B. longum UABl-14 and B. bifidum UABb-10 were studied in Martoni 2019 for digestive regularity. Few probiotic products can point to direct human RCT evidence for any of their specific strains; Xtra-Brain® has direct evidence for two.

Includes NutraFlora® FOS prebiotic fiber. NutraFlora® is Ingredion’s branded fructooligosaccharide prebiotic. FOS selectively feeds Bifidobacteria (the bifidogenic effect), supporting the Bifidobacterium strains in the blend. The synbiotic combination of probiotic strains plus targeted prebiotic fiber is a well-established formulation strategy. We are transparent that FOS itself was the null arm in Schmidt 2015 — the prebiotic mechanism we support is bifidogenic, not stress-modulating.

50 billion CFU per capsule. A robust CFU dose at the upper end of common multi-strain probiotic products. Manufactured by DaVinci Laboratories using their stabilized nondairy probiotic complex technology to maintain CFU viability through the product’s shelf life when stored properly.

EFSA QPS species. All Streptococcus thermophilus, Bifidobacterium, and Lactobacillus species in the blend hold Qualified Presumption of Safety status from the EFSA BIOHAZ Panel (2023 QPS update). In the US, these species carry a long history of safe use and generally GRAS status.

Dosage & timing

Xtra-Brain® serving

1 capsule

50 billion CFU + FOS prebiotic · Once or twice daily, between meals

Take 1 capsule once or twice daily, between meals — per the DaVinci Laboratories manufacturer guidance. Taking between meals (rather than with food) is a common probiotic best-practice approach, since lower stomach acid levels between meals may be more favorable for probiotic transit

Take consistently every day — probiotic effects depend on ongoing supplementation to maintain supportive populations in the gut microbiome

Allow 2–4 weeks of consistent daily use before evaluating effects; gut microbiome changes accumulate over time

Storage: store below 70°F; refrigerate after opening to maintain CFU viability through shelf life

Mild transient gas or bloating in the first few days of use is common and typically resolves as the gut microbiome adjusts

Safety & tolerability

Immunocompromised individuals and the critically ill should consult a physician before use. Rare cases of bacteremia or fungemia have been reported with probiotic use in immunocompromised patients, those with central venous catheters, short-gut syndrome, or critical illness. The PROPATRIA trial (Besselink et al. 2008) reported increased mortality with a multispecies probiotic in patients with predicted severe acute pancreatitis. Xtra-Brain® is intended for healthy adults; individuals with serious underlying medical conditions, immunosuppression, or who are critically ill should consult their healthcare provider before use.

General tolerability

All species in the blend hold EFSA Qualified Presumption of Safety (QPS) status
US: long history of safe use and generally GRAS status
Generally well tolerated in healthy adults at typical multi-strain probiotic doses
Mild transient gas, bloating, or GI changes in the first days are common and typically resolve
FOS at 246 mg (within the capsule weight) is far below the symptom-threshold doses (~10–15 g/day) at which FOS commonly produces FODMAP-related symptoms

Important cautions

Immunocompromised individuals (HIV, transplant, chemotherapy): consult physician before use
Central venous catheters, short-gut syndrome, or critical illness: consult physician
Acute pancreatitis: probiotic use is contraindicated; consult physician
Pregnancy and breastfeeding: consult healthcare provider before use
FODMAP-sensitive individuals: monitor for tolerance; FOS is fermentable
Storage matters: store below 70°F; refrigerate after opening to preserve CFU viability

Frequently asked questions

Does Xtra-Brain® improve cognition or mood?

The honest answer is more nuanced than supplement marketing often allows. The gut-brain axis is a real and well-characterized biological communication system between gut microbes and the central nervous system. Specific probiotic strains (mostly different from Xtra-Brain®’s UA strains) have been studied for associations with stress, mood, and cognitive measures in healthy adults — with results that are real but generally modest and inconsistent across the literature. The 2020 Marx meta-analysis of 22 RCTs (n=1,551) found no significant overall cognitive effect of pre/probiotics. Xtra-Brain®’s primary structure-function role is supporting digestive health and a healthy gut microbiome; the gut-brain axis framing reflects the scientific concept that gut health is connected to overall wellness, not a claim that this specific product produces specific cognitive or mood outcomes.

Why do you describe the gut-brain axis evidence as “different strains”?

Probiotic effects are strain-specific: findings for one probiotic strain do not automatically transfer to another strain, even of the same species. The published gut-brain axis research most commonly uses other strains than those in Xtra-Brain® — for example, B. longum 1714 (Allen 2016), L. helveticus R0052 + B. longum R0175 (Messaoudi 2011), L. rhamnosus JB-1 (Bravo 2011), or W-series multispecies blends (Steenbergen 2015). Xtra-Brain® contains UA-trademarked strains from CHR Hansen / UAS Laboratories: UABl-14 (B. longum, different from strain 1714), UABb-11, UABb-10, and others. We describe the gut-brain axis evidence at the concept level using its actual sources, and separately describe the strain-matched evidence (Martoni 2019, for digestive endpoints) so customers can see exactly what is and is not established about Xtra-Brain®’s specific strains.

What is FOS and what does it do?

FOS (fructooligosaccharides) is a type of prebiotic fiber that selectively feeds Bifidobacteria in the gut — the bifidogenic effect. The Bifidobacterium strains in Xtra-Brain® (UABb-11, UABb-10, UABl-14) benefit from FOS as a prebiotic substrate. FOS is fermented by gut bacteria into short-chain fatty acids that support gut barrier function and other gut-brain axis mechanisms. An important honesty point: in the Schmidt 2015 prebiotic study, the FOS arm did not produce the cortisol or attentional-bias effects that the B-GOS arm produced. We do not attribute stress or mood effects to FOS specifically; the prebiotic mechanism we support is bifidogenic (feeding the beneficial Bifidobacteria in the blend).

Can I take Xtra-Brain® with 5-Brain® or Xynaptic Drops™?

Yes. The three products operate on fundamentally different mechanisms. 5-Brain® supports neuronal mechanisms directly through six cognitive ingredients (Bacopa, Ginkgo, ALCAR, Sharp-PS®, Chocamine®, Meriva®). Xynaptic Drops™ provides targeted citicoline support for phosphatidylcholine synthesis and acetylcholine precursor delivery. Xtra-Brain® supports the gut microbiome and the gut-brain communication pathway. The three are mechanistically complementary — addressing distinct biological systems. As always, consult your healthcare provider if you take medications or have a medical condition.

What about the species name changes I see on the label?

In 2020, the original Lactobacillus genus was reclassified into 25 genera based on phylogenetic and genomic analysis (Zheng et al., Int J Syst Evol Microbiol). The familiar names (L. plantarum, L. casei, L. rhamnosus, L. salivarius) remain in widespread industry use and on product labels for continuity. The updated scientific names are Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lacticaseibacillus rhamnosus, and Ligilactobacillus salivarius respectively. L. acidophilus remains as Lactobacillus acidophilus. Streptococcus thermophilus and the Bifidobacterium species are not affected by the reclassification. We list both names on this page for transparency and scientific accuracy.

Why does the label say 52.5 billion CFU but you guarantee 50 billion?

Probiotic CFU counts naturally decline over a product’s shelf life, even with proper storage. Industry best practice is to manufacture above the labeled guarantee so that the guaranteed CFU level is maintained through expiration. Xtra-Brain® is manufactured at 52.5 billion CFU per capsule with a 50 billion CFU guarantee. To support viability through shelf life, store the product below 70°F and refrigerate after opening.

← All Nutropx ingredient research

References
Martoni CJ et al. (2019) J Dig Dis 20(9):435–46 · PMID 31271261 · Messaoudi M et al. (2011) Br J Nutr 105(5):755–64 · PMID 20974015 · Allen AP et al. (2016) Transl Psychiatry 6(11):e939 · PMID 27801892 · Tillisch K et al. (2013) Gastroenterology 144(7):1394–401 · PMID 23474283 · Steenbergen L et al. (2015) Brain Behav Immun 48:258–64 · PMID 25862297 · Schmidt K et al. (2015) Psychopharmacology 232(10):1793–801 · PMID 25449699 · Marx W et al. (2020) Neurosci Biobehav Rev 118:472–84 · PMID 32860802 · Benton D et al. (2007) Eur J Clin Nutr 61(3):355–61 · PMID 17151594 · Bravo JA et al. (2011) PNAS 108(38):16050–5 · PMID 21876150 (mechanism, animal) · Cryan JF, Dinan TG et al. (2019) Physiol Rev · DOI 10.1152/physrev.00018.2018 (review) · Martin AM et al. (2017) Endocrinology 158(5):1049 (serotonin biology) · Zheng J et al. (2020) Int J Syst Evol Microbiol 70(4):2782–858 · PMID 32293557 (taxonomy) · EFSA BIOHAZ Panel (2023) QPS update, EFSA Journal 21(7):8092 · Besselink MGH et al. (2008) Lancet 371(9613):651–9 · PMID 18279948 (PROPATRIA safety)

This page is for educational and informational purposes only. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before beginning any supplement regimen, particularly if you are pregnant, nursing, immunocompromised, have a central venous catheter, short-gut syndrome, acute pancreatitis, critical illness, or any underlying medical condition. Keep out of reach of children. Store below 70°F; refrigerate after opening to maintain probiotic viability through shelf life. UA Formulation Strain trademarks are trademarks of CHR Hansen A/S. NutraFlora® marks and logos are trademarks of the Ingredion group of companies.