IngredientsIn 2020, a comprehensive reclassification of the genus Lactobacillus proposed the genus Lacticaseibacillus, which includes the species Lacticaseibacillus paracasei to name the formerly called Lactobacillus paracasei. This reclassification, proposed by Zheng et al. (2020), was based on a polyphasic approach encompassing core genome phylogeny, conserved pairwise average amino acid identity, clade-specific signature genes, physiological criteria, and ecology of the organisms. The species is therefore now formally known as Lacticaseibacillus paracasei, though the historical name Lactobacillus paracasei remains prevalent in older literature and on many commercial product labels.
The high levels of DNA homology among strains belonging to L. casei subspecies led to a reclassification of L. casei subsp. casei (most strains) as Lactobacillus paracasei (Collins et al., 1989). Thus, most genomes designated as L. casei in the NCBI database correspond to L. paracasei. The bacterium comprises diverse Gram-positive bacteria that are very closely related to Lactobacillus casei, belonging to the Lactobacillus casei group. Due to extreme genome similarities between L. casei and L. paracasei, many strains have been cross-placed in the other group.
The species encompasses two recognized subspecies: L. paracasei subsp. paracasei and L. paracasei subsp. tolerans. The current valid name as of the 2020 taxonomic reclassification is Lacticaseibacillus paracasei. Commercially and in research contexts, the species is referred to by a range of strain designations including Lpc-37, F19, and CNCM I-1518, among others — with effects considered to be strain-specific.
Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Typical cell descriptors include: Gram-positive rods approximately 0.5–0.8 μm × 2.0–4.0 μm; peptidoglycan cell wall with teichoic acids; surface LPXTG-anchored proteins; and variable exopolysaccharide (EPS) production.
Typical genomes range approximately 2.9–3.1 Mb with ~46% GC content. Among 74 sequenced genomes of L. paracasei from GenBank, assembly sizes ranged from 2.3 to 3.3 MB and genome completeness between 88% and 100%. The pan-genome of 75 L. paracasei strains holds 15,945 gene families, while the core genome contained about 8.4% of the total genes.
The long history of use of Lactobacillus species in fermented products has led to their recognition as GRAS (generally recognized as safe) by the US Food and Drug Administration (FDA), and earned them a place on the QPS (qualified presumption of safety) list assembled by the European Food Safety Authority (EFSA).
Natural sources of L. paracasei include fermented dairy products (yogurt, kefir, cheese), fermented vegetables, and human mucosal isolates (oral and gut). Kefir grains can be considered natural reservoirs of safe and potentially probiotic strains. Studies on kefir grain microbiota have confirmed the presence of Lacticaseibacillus paracasei among other LAB species including Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactiplantibacillus plantarum, and Lactococcus lactis.
The species L. casei, L. rhamnosus, and L. paracasei are "nomadic" and can currently adapt to a wide variety of niches. L. paracasei strains have been found to display similar loss of genes in dairy isolates and high diversity among strains from other sources. The organism has been isolated from a diverse array of environments including traditional African corn-based beverages (mahewu), North African fermented dairy products (lben), Estonian semi-hard cheeses, and human vaginal isolates, indicating its broad ecological flexibility.
Commercial production uses fermentation, harvesting, cryoprotectants and lyoprotectants, and drying processes. In supplement and functional food contexts, L. paracasei is marketed in several forms:
Strains belonging to what is now Lacticaseibacillus paracasei have been part of traditional fermented foods such as yogurt, cheese, and fermented vegetables for centuries. Although L. paracasei itself was not isolated and named until relatively recently (late 20th century), its benefits were unknowingly harnessed through the traditional fermentation of milk and plant-based foods for centuries.
Across Europe, Central Asia, and the Middle East, fermented dairy and vegetable products were staple foods, valued not only for preservation but also for their health-enhancing properties. These foods — such as cultured buttermilk, kefir, and pickled vegetables — often fostered beneficial strains of bacteria including L. paracasei.
In folk medicine, sour milk and fermented drinks were frequently used to calm the stomach, relieve intestinal upset, and rebuild strength during convalescence. They were often prescribed to children and the elderly or used as a restorative after illness.
Historically, such fermented foods were consumed for preservation and flavor; modern use targets specific health endpoints validated in randomized trials at the strain level. A specific example of traditional use linked to verified L. paracasei strains is the North African fermented dairy product lben: Lben is a dairy fermented food that is largely consumed in Tunisia for its numerous health benefits that are related to the existence of probiotics. Similarly, the South African traditional fermented drink mahewu has been identified as a non-conventional isolation source for L. paracasei strains.
L. paracasei comprises diverse strains with a long history of safe use in food and agricultural applications that have been studied for their health-promoting characteristics.
One of the most extensively studied active components of L. paracasei is its capacity to produce exopolysaccharides. One of the main components of Lactobacillus's mechanism of action is EPS. Previous studies have shown that Lactobacillus-derived EPS possesses beneficial anti-inflammatory activities. In addition to the probiotic cells, the EPS produced by LAB has been reported to confer health benefits such as immune modulation, enhanced NK cell activity, antimicrobial activity, and antitumor activity.
EPS from L. paracasei IJH-SONE68 has been shown to significantly decrease accelerated serum IgE levels and the expression of IL-4 mRNA in contact dermatitis model mice. The EPS is thought to interact with pattern recognition receptors on the intestinal epithelium, modulating downstream immune signaling.
L. paracasei JY062 with its EPS (JEC) alleviated intestinal barrier damage caused by LPS. After JEC intervention on Caco-2 cells, this resulted in upregulation of ZO-1, Claudin-1, Occludin, and MUC2 transcript levels and decreased mRNA expression of Claudin-2. These tight junction proteins are critical to epithelial barrier integrity. Probiotics (especially Lactobacillus species) enhance gut health through various mechanisms, including immune modulation and strengthening of tight junction (TJ) protein expression and localization. These bacteria can also counteract epithelial damage caused by inflammatory mediators or pathogenic toxins by activating innate immune receptors such as Toll-like receptors (TLRs).
The mode of action of probiotics is complex and not yet fully elucidated. Many mechanisms have been reported to explain probiotic actions such as antagonism against intestinal pathogens, enhancement of mucosal barrier activity, or modulation of host immune functions.
L. paracasei JY062 with its EPS has been shown to significantly promote M1/M2 type macrophage balance and improve the Treg/Th17 immune axis imbalance. In allergic contexts, allergens promote the proliferation of T helper 2 (Th2) cells, resulting in IL-4 release followed by antigen-specific IgE production. L. paracasei preparations have been shown to shift this Th2-skewed response, partly through augmented Th1 cytokine signaling.
Heat-killed Lacticaseibacillus paracasei MCC1849 effectively induced IL-12 production in mouse spleen cells and significantly reduced cold symptoms in clinical trial subjects. L. paracasei 8700:2 significantly induced the phagocytic capacity of white blood cells in healthy adults and increased the number of natural killer (NK) T lymphocytes within 2 weeks of intake. This was interpreted as a priming of the immune system that could be beneficial, for example in the prevention of viral infections.
Research has shown that selected L. paracasei L2 strains express high adherence to HCT-116 cells (45.03%), survived under acidic conditions (pH 3), and showed resistance to bile salts. Research has confirmed that L. paracasei's health-promoting properties include its ability to inhibit intestinal pathogens, modulate immune responses, improve lipid metabolism, and exert hypocholesterolemic and stress-reducing effects. One characterized strain, TISTR 2593, exhibited a survival rate of 91.23% after a 3-hour incubation in highly acidic conditions (pH 2.0) and 88.72% after incubation in bile salt solution.
Some L. paracasei strains have been shown to modulate gut microbial composition in ways that affect SCFA output. Lactobacillus paracasei CNCM I-1572, despite not significantly improving IBS symptoms in one pilot trial, induced a significant reduction in the genus Ruminococcus and a significant increase in the SCFAs acetate and butyrate in IBS patients.
As a lactic acid bacterium, L. paracasei ferments glucose into lactic acid (also used as the food additive E 270). Lactic acid production contributes to the colonization resistance of the intestine by lowering luminal pH, which is unfavorable for many pathogenic microorganisms.
Several clinical trials have examined L. paracasei in IBS, with mixed outcomes across strains.
In a randomized, double-blind, placebo-controlled study, the efficacy of Lactobacillus paracasei HA-196 and Bifidobacterium longum R0175 in reducing gastrointestinal and psychological symptoms of IBS was evaluated in 251 adults with either constipation (IBS-C), diarrhea (IBS-D), or mixed-pattern (IBS-M). Following a 2-week run-in period, participants were randomized to L. paracasei (n = 84), B. longum (n = 83), or placebo (n = 81). IBS symptoms, stool frequency and consistency, and quality of life were assessed by questionnaires. The differences from baseline in the severity of IBS symptoms at 4 and 8 weeks were similar between groups. This suggests that L. paracasei HA-196 as a single strain was not demonstrably superior to placebo for IBS symptom severity in that trial.
A pilot study assessed the effects of Lactobacillus paracasei CNCM I-1572 on clinical and gut microbiota-related factors in IBS. A multicenter, randomized, double-blind, crossover, 18-week, placebo-controlled pilot trial enrolled 40 IBS patients from five Italian centers. Lactobacillus paracasei CNCM I-1572 did not significantly improve IBS symptoms, including primary efficacy variables of worst abdominal pain/discomfort and IBS degree of relief. Interestingly, however, L. paracasei CNCM I-1572 induced a significant reduction in genus Ruminococcus, a significant increase in the SCFAs acetate and butyrate, and a reduction in immune activation markers.
Among specific strains, Lactobacillus paracasei NCC2461 has shown some efficacy at reducing gastrointestinal symptoms of IBS, such as frequency of bowel movements, pain, and visceral hypersensitivity, in earlier work. A clinical study exploring the effects of Lactobacillus paracasei F19 on IBS symptoms reported an improvement in the bowel habits of participants with constipation or diarrhea.
Evidence assessment: The overall clinical evidence for L. paracasei in IBS is mixed and highly strain-dependent. While some microbiological changes (SCFA elevation, microbiota modulation) are documented in trials, direct improvements in primary IBS symptom scores have not been consistently demonstrated. Larger, well-powered RCTs for individual strains are lacking.
Allergic rhinitis is one of the most studied clinical indications for L. paracasei-based interventions, with a body of evidence centered on the strain LP-33 and related strains.
To test the efficacy of the probiotic Lactobacillus paracasei subsp. paracasei LP-33, a double-blind, placebo-controlled, randomized trial was carried out in patients with allergic rhinitis (AR) to grass pollen treated with loratadine and presenting altered quality of life. Subjects with persistent AR, symptomatic during the grass pollen season, and a positive skin test or specific IgE to grass pollens were included. All received loratadine for 5 weeks. The primary endpoint was the improvement in Rhinitis Quality of Life (RQLQ) global score at the fifth week of LP-33 consumption compared with placebo.
A double-blind, prospective, randomized, placebo-controlled trial examined the efficacy and safety of Lacticaseibacillus paracasei GM-080 in a mouse model of airway hyper-responsiveness and in children with perennial allergic rhinitis (PAR).
A 12-week, double-blind, randomized, placebo-controlled study evaluated the effect of Lactobacillus paracasei (HF.A00232) in children aged 6–13 years with perennial allergic rhinitis.
A systematic review provided significant evidence of beneficial clinical and immunologic effects of L. paracasei LP-33 strains in the treatment of allergic rhinitis. Ingestion of LP-33-fortified fermented milk for 30 days can effectively and safely improve the quality of life of patients with allergic rhinitis, and may serve as an alternative treatment.
Although evidence of a beneficial effect of probiotics on allergic respiratory symptoms is still conflicting, a few studies conducted in children and adults with allergic rhinitis suggested a beneficial effect of the consumption of specific probiotic strains belonging to the Lactobacillus paracasei species.
In one pediatric RCT, the intervention group was provided a daily single dose of a chewable tablet containing 2 × 10⁹ CFU of Lactobacillus paracasei LP-33 for 6 weeks, while the control group received cetirizine.
Evidence assessment: Multiple RCTs, spanning both children and adults, have evaluated L. paracasei strains (especially LP-33 and GM-080) in allergic rhinitis. Results across these trials are generally positive for symptom and quality-of-life measures, though effect sizes are moderate, results vary by strain, and comparisons to antihistamine therapy remain limited. The evidence base is more consistent for allergic rhinitis than for most other indications studied to date.
In reactive skin, oral Lactobacillus paracasei NCC 2461 taken for 2 months decreased skin sensitivity and accelerated barrier-function recovery. Animal and human studies suggest that the anti-allergic mechanism of relevant strains involves modulation of Th2 cytokines and IgE production, consistent with findings in allergic rhinitis models.
In a randomized, double-blind, placebo-controlled clinical trial of L. paracasei IJH-SONE68, sixty subjects were instructed to orally take a capsule containing the IJH-SONE68 powder or placebo every day for 12 weeks. After the clinical trial, scores based on subjects' self-assessment of allergic status were significantly improved in the intervention group compared with the placebo group. This trial included subjects with chronic allergic conditions including skin manifestations.
Evidence assessment: The evidence for skin health benefits (atopic dermatitis, reactive skin) is preliminary. Some strains show promising results in small trials or in composite allergic populations, but dedicated, large-scale RCTs specifically for atopic dermatitis using L. paracasei remain limited.
Arguably one of the strongest clinical evidence bases for L. paracasei involves reduction in cold frequency and severity, particularly for the strain 8700:2 used in combination with Lactiplantibacillus plantarum HEAL9.
In two earlier studies by Berggren et al. and Busch et al., the combination of L. plantarum HEAL9 and L. paracasei 8700:2 was found to reduce the incidence, severity, and duration of common cold episodes. The same combination was also shown to be of benefit against self-reported cold infections in a population of Swedish children aged 1–6 years attending day care.
A subsequent confirmatory multicenter trial conducted at 14 sites in Germany was undertaken to confirm previously reported results on the efficacy of L. plantarum HEAL9 and L. paracasei 8700:2 against the common cold in healthy adults.
Previous clinical studies showed that heat-killed Lacticaseibacillus paracasei MCC1849 suppresses subjective symptoms among healthy adults, though the mechanism underlying this beneficial effect remained unclear. A randomized, double-blind, placebo-controlled, parallel-group study enrolled 100 healthy adults, divided into MCC1849 or placebo groups. Participants ingested test powder with 5 × 10¹⁰ MCC1849 cells or placebo powder for 4 weeks.
L. paracasei MCC1849 has the potential to improve resistance to common cold infections in susceptible subjects and maintain a desirable mood state, even under mental stress conditions.
Evidence assessment: The combination of L. paracasei 8700:2 with L. plantarum HEAL9 has the best-supported evidence for reduction of common cold incidence in adults, across multiple trials. Heat-killed preparations (MCC1849) also show clinical promise for immune support. However, the confounding factor of multi-strain use and strain specificity limits generalization to L. paracasei alone.
Probiotics have received wide attention as a potential way to alleviate gastrointestinal (GI) motility disorders. Research investigated the effects of Lacticaseibacillus paracasei JY062 at 5 × 10⁹ CFU/mL on mice induced by loperamide. After two weeks of probiotic intervention, the probiotic combination alleviated GI motility disorder by increasing the secretion of excitatory GI regulators motilin, gastrin, and 5-hydroxytryptamine (5-HT) and decreasing the secretion of inhibitory GI regulators peptide YY and nitric oxide. This work is preclinical (animal model), and direct translation to human clinical outcomes requires further validation.
Modulating microbial metabolism via probiotic supplementation has been proposed as an attractive strategy for the prevention of cardiometabolic diseases. Lacticaseibacillus paracasei was reported to alleviate metabolic disorders in murine models, however, its beneficial effects in humans remain to be determined. One RCT evaluated whether L. paracasei supplementation could improve endothelial function and cardiometabolic health in subjects with metabolic syndrome (MetS) in a randomized, double-blind, placebo-controlled trial among 130 participants.
Research has explored L. paracasei's health-promoting properties, including its ability to improve lipid metabolism and exert hypocholesterolemic effects. Many foods fermented by LAB possess additional health-promoting benefits such as imparting improvements to digestion and tolerance to lactose, hypocholesterolemic and antihypertensive effects, and antioxidant and anticarcinogenic activities.
Evidence assessment: Preclinical evidence for cardiometabolic effects (lipid metabolism, anti-obesity) is substantial but largely limited to animal models. Human RCT evidence for cardiometabolic outcomes is still emerging, and definitive conclusions await larger-scale human trials.
L. paracasei ST11 (NCC2461) was shown to strongly decrease colitis development in a preventive protocol in an adoptive transfer mouse model. Oral administration of ST11 was safe and had a significant preventive effect on colitis. These results demonstrate that probiotics such as Lactobacillus paracasei harbor worthwhile in vivo immunomodulatory properties to prevent intestinal inflammation by nutritional approaches.
The therapeutic effect of probiotics has been studied in a number of clinical trials for the treatment of IBD, showing that the use of probiotics might be recommended for anti-inflammatory therapy in UC patients. A formulation of live bacteria including L. paracasei may be used in combination with conventional therapies to treat ulcerative colitis.
Evidence assessment: The preclinical evidence for L. paracasei in IBD/colitis is substantial. However, robust, large-scale human RCTs specifically for L. paracasei in IBD are currently lacking. The clinical recommendation to use probiotics in UC is more broadly derived from multi-strain or general probiotic evidence bases.
The Lacticaseibacillus paracasei DG strain significantly induced the expression of genes involved in protective antiviral immunity and prevented the expression of proinflammatory genes triggered by SARS-CoV-2 infection. This observation is based on in vitro and preliminary data and has not been confirmed in large prospective human trials.
Oral administration of heat-killed Lactobacillus paracasei MoLac-1 increased the proportion of NK cells in spleen and ameliorated the symptoms of influenza virus (IFV) infection in mice.
Evidence assessment: Antiviral and general immune-stimulating properties are documented in vitro and in animal models, with some human data for cold prevention. Evidence for specific viral disease management remains preliminary.
Dosage and preparation in clinical studies are strongly strain-specific. The following figures are drawn directly from peer-reviewed sources:
No universally established "standard dose" for L. paracasei supplements exists; effective doses differ by strain, indication, and population studied.
The long history of use of Lactobacillus species in fermented products has led to their recognition as GRAS (generally recognized as safe) by the US FDA and earned them a place on the EFSA QPS list. The qualified presumption of safety (QPS) approach was developed by EFSA to provide a generic pre-evaluation of the safety of biological agents. The QPS approach is based on an assessment of published data for each agent with respect to its taxonomic identity, the body of relevant knowledge, and safety concerns. Safety concerns are, where possible, confirmed at the species/strain or product level and reflected by qualifications.
Antibiotic susceptibility is a required safety characteristic for probiotic strains intended for food or supplement use. Antibiotic MIC tests indicated that L. paracasei NTU 101 is only resistant to chloramphenicol. In accordance with EFSA (2012) guidelines, this strain was investigated for the presence of resistance genes; no genes associated with chloramphenicol resistance were detected. Separately, the L. paracasei LPC-S01 isolate was demonstrated to be susceptible to antibiotics indicated by EFSA and does not produce biogenic amines.
In safety evaluations, L. paracasei TISTR 2593 exhibited non-hemolytic activity (γ-hemolysis) when cultivated on sheep blood agar. The absence of hemolytic activity is a fundamental criterion for selecting probiotic strains, ensuring the nonvirulent nature of the strain, according to FAO/WHO guidelines.
In healthy individuals, L. paracasei has a well-established safety record at typical probiotic doses. However, rare cases of bacteremia associated with L. paracasei have been documented in severely immunocompromised individuals:
Two papers in a recent EFSA QPS review dealt with L. paracasei infections. All of the safety-concern cases described occurred in individuals with severe systemic pathologies leading to immunodepression. Ukai et al. (2025) reported a case of Lacticaseibacillus paracasei bacteraemia in an 8-month-old girl following a jejunostomy for hypoganglionosis who had been taking a probiotic preparation containing L. paracasei. Similarly, a case of L. paracasei infection of a total hip prosthesis has been documented, illustrating that device-associated infections are a theoretical risk in compromised hosts.
In the 2024 EFSA QPS review update, two papers dealt with L. paracasei infections; the identification methodology was not clear in two of these papers, while MALDI-TOF MS was used in the others. The EFSA panel has not recommended removal of L. paracasei from the QPS list on the basis of these sporadic reports.
Functional traits such as acid resistance, adhesion, and immunomodulation are strain-dependent and cannot be generalized by species name alone. This principle is recognized across safety and efficacy evaluations: results obtained with one strain do not automatically apply to other strains designated as L. paracasei. The high degree of genome diversity within the species — a pan-genome of 75 strains holds 15,945 gene families — supports the understanding that inter-strain variation in both safety and functional characteristics can be substantial.
Simultaneous administration of broad-spectrum antibiotics is expected to reduce the viability of ingested L. paracasei cells, potentially diminishing any functional probiotic benefit. No clinically significant adverse drug interactions specific to L. paracasei and commonly prescribed medications have been reported in the peer-reviewed literature reviewed here, beyond the general principle that antibiotics may suppress the administered organism. LAB-based probiotics can possess the ability to impart improvements to the intestinal barrier and commensal microbial balance, produce beneficial enzymes and neurochemicals, suppress pathogenic microflora, and modulate the immune system. This immune-modulatory activity is theoretically relevant in the context of immunosuppressive therapy, for which the evidence base is insufficient to draw firm conclusions.
Health conditions that Lactobacillus paracasei may help support.
L. paracasei NCC2461 improved stress-induced visceral pain and restored gut permeability in preclinical models. A pilot RCT of L. paracasei CNCM I-1572 in 40 IBS patients found significant increases in fecal SCFAs (acetate, butyrate) and reduction of IL-15, providing biologically plausible mechanisms for abdominal symptom relief, even though primary pain endpoints were not significantly improved.
Multiple strains of L. paracasei, notably LP-33 and GM-080, have been evaluated in randomized controlled trials for respiratory allergy. The LP-33 strain administered for 30 days improved quality of life in allergic rhinitis patients. Mechanistically, L. paracasei shifts the Th1/Th2 cytokine balance, reducing Th2-driven IgE and IL-5. Results across trials are mixed, with some studies showing no significant benefit, indicating strain- and study-design dependency.
L. paracasei PS23 and Lpc-37 have been studied in RCTs for anxiety and stress outcomes. A 6-week double-blind RCT of live PS23 in stressed office workers showed significant improvement in trait anxiety levels versus placebo. The gut-brain axis mechanism involves modulation of corticosterone, anti-inflammatory cytokines, and intestinal barrier integrity.
L. paracasei HII01 was tested in a randomized, double-blind, placebo-controlled trial in type 2 diabetic patients over 12 weeks, demonstrating significant reduction in fasting blood glucose and inflammatory markers. Animal and in vitro studies with multiple L. paracasei strains show inhibition of α-glucosidase, enhanced GLUT4 expression, and improved insulin signaling.
Lactobacillus paracasei 8700:2 was evaluated in a 2021 randomized placebo-controlled trial in children with celiac disease autoimmunity (PMID 34249990) alongside L. plantarum HEAL9. L. paracasei was also included in the VSL#3 blend tested in an adult CeD RCT. Celiac.com (2017) reported trial data on L. paracasei 8700:2 for immune support and potential delay of CeD immune activation.
L. paracasei strains have been tested in RCTs for children's gut health, including a synbiotic containing L. paracasei B21060 for acute diarrhea and L. paracasei N1115 for gut development in infants and toddlers. L. paracasei ST11 ameliorated non-rotavirus diarrhea in Bangladeshi children. Evidence is strain-specific and results vary across trials.
L. paracasei has been tested in pediatric immune contexts including asthma, allergic rhinitis, and celiac disease autoimmunity. A double-blind RCT in 160 asthmatic children showed L. paracasei (LP) alone or combined with L. fermentum improved asthma severity scores and immune biomarkers over 3 months. GM-080 ameliorated sneezing and global assessment scores in children with perennial allergic rhinitis.
L. paracasei TISTR 2593 was tested in a randomized, double-blind, placebo-controlled clinical trial in hypercholesterolemic subjects measuring serum lipid profile, oxidative stress, and inflammation. L. paracasei DTA81 significantly reduced total cholesterol in mice on a high-fat diet. Multiple strains exhibit in vitro cholesterol assimilation capacity.
L. paracasei 8700:2 combined with L. plantarum HEAL9 significantly reduced the incidence and severity of community-acquired common colds in a large RCT of 898 healthy adults. L. paracasei (L. casei 431) enhanced immune response to influenza vaccination in a 1,104-subject RCT and reduced upper respiratory symptom duration.
L. paracasei E10 significantly alleviated colitis symptoms in a dextran sulfate sodium (DSS) mouse model by reducing disease activity index, preserving colonic architecture, increasing goblet cell density, and upregulating tight junction proteins. A clinical trial (NCT07017959) is currently investigating L. paracasei D3.5 for IBD in adults, though published human RCT data are limited.
Lactobacillus paracasei is a probiotic included in multi-strain formulations with demonstrated RCT evidence for improving constipation. It was part of a 30-day parallel-group RCT (PMC9622669) where probiotic cocktails containing L. paracasei with other strains significantly improved stool frequency and quality from the first week. Meta-analyses of probiotic trials including L. paracasei confirm significant stool frequency improvement.
L. paracasei CCFM1229 reduced depressive and anxiety behavior in a chronic stress mouse model by regulating xanthine oxidase activity in the brain and maintaining CNS myelin structural stability. Human RCT data for L. paracasei specifically targeting depression are limited, but the PS23 RCT in stressed office workers assessed depression as a secondary outcome.
Lactobacillus paracasei (especially K71 strain) is specifically identified in systematic reviews as one of the strains with the strongest evidence for reducing AD severity and improving immunological markers. Multiple RCTs support its use in atopic dermatitis in adults.
Multiple L. paracasei strains have clinical evidence for diarrhea management. L. paracasei B21060 in a synbiotic formulation showed efficacy in acute childhood diarrhea, and ST11 ameliorated non-rotavirus diarrhea in children. L. paracasei CNCM I-1572 modulated gut microbiota and increased fecal butyrate in IBS, although primary symptom endpoints were not significantly improved.
Lactobacillus paracasei is specifically supported by dedicated RCTs in diverticular disease. A 2025 post-hoc analysis of a 12-month, double-blind, placebo-controlled RCT found L. paracasei CNCM I-1572 significantly better than placebo in preventing the first episode of acute diverticulitis in SUDD patients. An earlier 50-patient RCT showed L. paracasei F19 plus high-fiber diet was significantly superior to high-fiber diet alone for reducing abdominal pain and bloating.
Lactobacillus paracasei has demonstrated anti-allergic effects in atopic dermatitis. In vitro studies show it modulates cytokine profiles in allergic children toward Th1 (anti-allergic) responses, and it is listed among probiotic strains with evidence of efficacy in AD in clinical systematic reviews.
L. paracasei strains modulate IgE-mediated allergic responses and have been studied for atopic dermatitis, chronic allergy, and celiac disease autoimmunity. L. paracasei IJH-SONE68 improved chronic allergy status in a 12-week double-blind RCT. Multiple strains reduce serum IgE and Th2 cytokines associated with allergic sensitization.
L. paracasei DSMZ16671 specifically co-aggregates mutans streptococci (key caries/gum pathogens) in vitro and in human saliva, promoting their oral clearance without disrupting commensal flora. A short-term pilot RCT in humans using sugar-free candies as delivery vehicle was conducted, supported by animal data showing reduced caries scores.
Lactobacillus paracasei (Lacticaseibacillus paracasei) is a commercially important probiotic species with multiple clinical studies demonstrating gut microbiota modulation, improved gut barrier function, and beneficial effects on IBS and atopic conditions through microbiome-mediated immune modulation.
Lactobacillus paracasei is a gut-brain axis probiotic with evidence for stress reduction and HPA axis modulation. It contributes to the gut microbiome's capacity to regulate mood-related neurotransmitters and has been included in multi-strain psychobiotic formulations studied for anxiety and cognitive outcomes.
L. paracasei BEPC22 (in a dual-strain product with L. plantarum BELP53) significantly reduced body fat percentage, body fat mass, body weight, and BMI in overweight adults in a 12-week RCT. L. paracasei K56 at 10⁹ CFU/day for 60 days reduced body fat mass, body fat percentage, visceral fat area, and waist circumference in obese individuals.
Lactobacillus paracasei has been studied in IBS and functional GI disorders within multi-strain probiotic formulas showing clinical benefit. Strain combinations including L. paracasei HEAL9 with L. plantarum 8700:2 have demonstrated efficacy in GI symptom reduction in RCTs. It is included in evidence-based probiotic guidance for functional bowel disorders.
Lactobacillus paracasei has shown anti-inflammatory activity in IBD models and clinical studies, improving UC activity indices and modulating gut microbiota. It is included in clinical multi-strain probiotic IBD formulations with demonstrated efficacy.
L. paracasei NCC2461 restored gut permeability in preclinical stress models. L. paracasei CNCM I-5220-derived postbiotic has been specifically studied for protection against leaky gut. L. paracasei HII01 significantly reduced plasma LPS (a marker of intestinal permeability) in T2DM patients in an RCT, consistent with improved barrier function.
Lactobacillus paracasei has been evaluated in oral health contexts, with strain SD1 shown to reduce S. mutans and progression of dental caries. Metagenomic analyses in experimental periodontitis models showed that L. paracasei L9 significantly altered subgingival microbiome composition and reduced pathogenic bacterial genera.
L. paracasei LP-33 has been specifically studied in randomized, placebo-controlled trials during pollen seasons for hay fever. Active treatment groups reported fewer sneezing episodes, less nasal congestion, and improved quality of life compared to placebo. The immunomodulatory mechanism involves rebalancing Th1/Th2 cytokine ratios and reducing allergic IgE responses.
Lactobacillus paracasei strains are among the most consistently studied probiotics for seasonal allergic rhinitis. A 2016 meta-analysis of 22 RDBPCTs found all five L. paracasei studies demonstrated clinically significant symptom improvements vs. placebo, with significant reductions in nasal (SMD -1.23, p<0.001) and ocular (SMD -1.84, p<0.001) symptom scores.
L. paracasei Lpc-37 and PS23 have been evaluated for perceived stress reduction in clinical trials. Lpc-37 has shown reductions in perceived stress in healthy adults in prior studies, and the ChillEx RCT specifically modeled chronic examination stress in university students. PS23 improved salivary stress biomarkers and antioxidant levels alongside anxiety and sleep measures.
L. paracasei strains have been studied in RCTs for upper respiratory tract infections (URTIs), including a study showing reduced URTI duration in elderly consuming L. paracasei N1115-supplemented yogurt, and the L. casei 431 RCT measuring upper respiratory symptom incidence and duration in 1,104 adults around influenza vaccination.
Lactobacillus paracasei is listed among recognized probiotic Lactobacillus strains with documented roles in the urinary microbiome and is identified in the vaginal Döderlein flora connected to urinary tract health. It is noted in Frontiers Cellular and Infection Microbiology (2025) as a urogenitally relevant probiotic organism. In vitro studies support its role in inhibiting uropathogens through competitive exclusion and antimicrobial compound production.
Lactobacillus paracasei is a native vaginal isolate identified in healthy women's vaginal microbiome and is listed among lactobacilli with probiotic potential for vaginal health. It has been isolated from healthy vaginal swabs and screened as a probiotic candidate with antimicrobial properties against vaginal pathogens. Evidence is primarily from in vitro and microbiome profiling studies.
Body systems that Lactobacillus paracasei may help support.
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