KT-11 HP is a powder of heat-treated (heat-killed) lactic acid bacteria, Lactobacillus crispatus strain KT-11. The KT-11 strain was isolated from the intestinal flora of healthy, vaginally born infants. L. crispatus is a lactic acid species found in large numbers in the female birth canal, where it suppresses the growth of pathogenic bacteria. These bacteria pass from mother to child during birth and form an infant's first line of defense against allergy and infection - a biological origin that gives KT-11 a distinctive position among immune-active ingredients.
Because KT-11 HP is heat-killed rather than live, it is a postbiotic: a stable, inactivated ingredient that delivers consistent biological activity without the cold-chain, viability and processing constraints of live probiotics.
KT-11 HP is positioned for multifunctional immune formulation. Documented directions of activity include immune modulation through correction of the Th1/Th2 balance, anti-allergic action, support for oral-cavity health, antiviral activity, and improvement of the intestinal microflora.
The ingredient is suitable for tablets, capsules, granules, foods and beverages, and its thermal stability makes it well suited to processed and heat-treated formats. Typical product directions include:
KT-11 HP is highly concentrated. Just 0.025 g of raw material delivers a 10 billion cell label claim, so 1 kg yields about 40,000 servings at that level. Published study intakes range from roughly 20 to 100 billion cells per day, and gut-flora work used 50 mg of KT-11 (about 20 billion cells) together with 3 g of oligosaccharides.
KT-11 is protected by four Japanese patents covering the strains and anti-allergic, immune and cosmetic compositions, and carries a Japanese health-food safety registration (JHNFA, reg. 16A002). It holds broad regulatory access for global formulation:
Production runs through controlled fermentation in 12,000-liter vessels, followed by concentration and washing, heat sterilization at 90 degrees C for 30 minutes, spray drying, 80-mesh sieving and quality control before shipment. Safety has been supported by single- and repeat-dose studies in animals and humans, an Ames test and a micronucleus test, all without adverse findings.
Postbiotics are defined by the International Scientific Association for Probiotics and Prebiotics (ISAPP) as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host" (Salminen et al., Nature Reviews Gastroenterology and Hepatology, 2021). KT-11 HP fits this definition precisely: its activity comes from intact heat-killed cells and their cell-wall components rather than from living, replicating bacteria. The strain has been studied across more than a decade of peer-reviewed research, summarized below by mechanism and outcome.
A pilot randomized, double-blind, placebo-controlled trial in healthy adults found that four weeks of heat-sterilized KT-11 supplementation produced a significantly higher CD3+ T-cell count versus placebo, with a higher CD8+CD28+ T-cell count in the female subgroup, alongside fewer self-reported cold-like symptoms, particularly fatigue (Nutrition Research, 2024).
In animal models, KT-11 significantly increased intestinal immunoglobulin A (IgA) and upregulated genes linked to antibody production and innate immunity, acting through Peyer's patch cells (Journal of Nutritional Science and Vitaminology, 2010). Mechanistic work shows that protein extracts of KT-11 promote interleukin-12p40 production via Toll-like receptor 2 (TLR2), a key pathway in directing the immune response (Journal of Food Biochemistry, 2021).
Heat-treated KT-11 raised the ratio of IFN-gamma+CD4+ to IL-4+CD4+ cells and increased expression of TLR2, NOD1 and NOD2, while lowering serum IgE - a profile consistent with shifting an allergy-prone Th2-dominant state toward balance (Journal of Agricultural and Food Chemistry, 2009). In an allergic-rhinitis model, KT-11 significantly reduced sneezing and ovalbumin-specific IgE (Animal Science Journal, 2010).
A randomized, double-blind clinical trial in healthy volunteers reported that daily intake of a KT-11 tablet (about 12 billion cells) for four weeks reduced the periodontal pathogen Porphyromonas gingivalis versus placebo, with improvements in plaque score, gum redness and gingival swelling in the female subgroup (Beneficial Microbes, 2018).
An S-layer protein on the surface of KT-11 competitively binds viral targets: a purified KT-11 S-layer protein significantly inhibited human rotavirus (strain DS-1) infection of intestinal epithelial cells in a dose-dependent manner, and remained effective after simulated gastric digestion (Frontiers in Microbiology, 2022). This surface-protein mechanism complements the strain's documented influenza-model activity.
Across these studies the active triggers are cell-wall and surface components - peptidoglycan, lipoteichoic acid and S-layer protein - not metabolic activity, which is why the heat-killed form retains immunological function. For product developers this translates into practical advantages: no refrigeration, stable cell counts through shelf life, tolerance of high-temperature processing, and predictable dosing.
KT-11 HP is a postbiotic - heat-killed (inactivated) cells of Lactobacillus crispatus strain KT-11. Under the ISAPP definition (2021), a postbiotic is a preparation of inanimate microorganisms and/or their components that confers a health benefit. Because the cells are not live, KT-11 HP needs no refrigeration, keeps a stable cell count through shelf life and tolerates high-temperature processing, while retaining the immune activity carried by its cell-wall and S-layer proteins.
KT-11 has more than a decade of peer-reviewed research. Human randomized double-blind trials show higher CD3+ T-cell counts and fewer cold-like symptoms (Nutrition Research, 2024) and reduced periodontal pathogen P. gingivalis with improved gum condition (Beneficial Microbes, 2018). Mechanistic studies document Th1/Th2 rebalancing and lower IgE (Journal of Agricultural and Food Chemistry, 2009), IL-12p40 induction via TLR2 (Journal of Food Biochemistry, 2021), increased intestinal IgA (Journal of Nutritional Science and Vitaminology, 2010) and rotavirus inhibition by its S-layer protein (Frontiers in Microbiology, 2022).
KT-11 holds GRAS status in the United States and is included in the EFSA QPS (Qualified Presumption of Safety) list in the European Union, and is registered as a food raw material in Taiwan, South Korea and China. It is allergen-free (none of the 28 mandatory allergens) and carries a Japanese health-food safety registration, making it straightforward to position across major supplement and functional-food markets.
KT-11 HP guarantees a minimum of 400 billion cells per gram. A 10 billion cell serving requires only 0.025 g of raw material, so 1 kg provides about 40,000 servings at that level. Published study intakes range from roughly 20 to 100 billion cells per day, giving formulators flexibility to set a claim-appropriate dose at low cost-in-use.
