Natto (Fermented Soybeans, Bacillus subtilis var. natto)
Natto is a traditional Japanese food of whole soybeans fermented with Bacillus subtilis var. natto. It is a rich food source of vitamin K2 as menaquinone-7 (MK-7), and it also carries the enzyme nattokinase, soy isoflavones, the sticky polymer poly-gamma-glutamic acid and live Bacillus spores. Besides the fresh food, it is sold as freeze-dried natto and as dried natto powder in capsules. Eating natto raises blood MK-7 and the activated form of osteocalcin. In small randomized meal tests, natto rich in poly-gamma-glutamic acid lowered the early blood sugar rise after white rice. Randomized trials did not show a change in bone density, while Japanese cohort studies, which are observational, link habitual natto intake with less bone loss and fewer fractures. Natto strongly counteracts warfarin, and it can cause a delayed allergic reaction hours after eating.
Benefits
Blood sugar rise after a white rice meal
In two small randomized crossover meal tests in Japanese adults without diabetes, adding 40 g of natto rich in poly-gamma-glutamic acid to white rice lowered the glucose rise over the first 30 to 45 minutes compared with natto low in this polymer, and in the first test lowered the 2-hour glucose response by about 20 percent versus rice alone. Each test used a single meal, not daily intake.
Vitamin K2 (MK-7) blood levels and osteocalcin activation
Eating natto raises blood MK-7 for at least 2 days: in one test, plasma MK-7 rose about eightfold 5 hours after a serving. In small feeding studies and in a 1-year trial of natto capsules, carboxylated (active) osteocalcin rose and the undercarboxylated form fell. These are blood markers of vitamin K use, not a bone outcome by themselves.
Bone density in randomized trials of natto
In a 1-year randomized trial in 73 premenopausal women, natto at lunch up to three times a week did not change heel bone stiffness, though a bone formation marker was higher in the three-times-a-week group than in the once-a-week group. In 334 postmenopausal Norwegian women, natto capsules supplying 360 mcg of MK-7 a day for 1 year did not change bone loss at any site versus placebo.
Bone loss and fractures in Japanese cohort studies
These are observational food-intake studies, not trials. Postmenopausal Japanese women who ate natto more often lost less bone at the femoral neck over 3 years, and women eating 7 or more packs a week had fewer osteoporotic fractures over a median 15 years. In older men, the link with hip density disappeared after accounting for a vitamin K blood marker.
Gut bacteria after natto powder capsules
In an open study with a no-intake control group, 1,140 mg a day of a natto powder capsule product for 62 days was followed by a rise in Bifidobacterium in men and women and in Blautia in men. There was no placebo, results were mostly within-group changes, two authors worked for the product's maker and several for the company that ran the analysis, and bowel habits did not change.
Mechanism of action
Vitamin K2 and gamma-carboxylation
MK-7 from natto is a form of vitamin K, the cofactor that activates vitamin K dependent proteins such as osteocalcin and the clotting factors. Natto intake raises blood MK-7 and carboxylated osteocalcin, and the same vitamin K activity is why natto counteracts warfarin, a drug that works by suppressing vitamin K function.
Viscous poly-gamma-glutamic acid and the early glucose rise
Poly-gamma-glutamic acid is the sticky polymer made during natto fermentation, and its amount depends on the Bacillus strain. The trial authors suggest it may slow the early glucose rise the way viscous fibers such as beta-glucan do, by slowing gastric emptying, but they state the mechanism remains unclear.
Live Bacillus subtilis var. natto and its MK-7
Fresh natto carries a very large number of live B. subtilis var. natto, and powder capsules carry its spores. Boiling natto cut the live bacterial count and its MK-7 content, and boiled natto produced a much smaller rise in plasma MK-7 than untreated natto.
Clinical trials
Randomized crossover pilot meal test with participants blinded to the meal (the authors note blinding may have been incomplete because the two natto types differed in texture and flavor); white rice alone (150 g), rice plus 40 g low-PGA natto, or rice plus 40 g high-PGA natto (natto from Takano Foods); primary outcome glucose area under the curve over 0 to 120 minutes; registered UMIN000030182; funded by the Japanese Ministry of Agriculture, Forestry and Fisheries; no conflicts declared (Araki et al. 2020, Nutrients)
21 healthy adults aged 20 to 64 enrolled; 20 completed all three meal tests.
The 0 to 120 minute glucose response was 20.1 percent lower after the high-PGA natto meal and 15.4 percent lower after the low-PGA natto meal than after rice alone; only the high-PGA difference was significant (p < 0.05). The 0 to 15, 0 to 30 and 0 to 45 minute responses were lower after high-PGA than low-PGA natto. The authors call the study exploratory and did not adjust for multiple tests.
Randomized crossover meal test; white rice with 40 g natto containing 439.6 mg (high) or 57.6 mg (low) of poly-gamma-glutamic acid; primary outcome glucose area under the curve 0 to 30 minutes, high versus low; registered UMIN000037449; funded by the Japanese Ministry of Agriculture, Forestry and Fisheries; no conflicts declared (Araki et al. 2020, Nutrients)
36 adults without diabetes selected for relatively high glucose after rice: 29 men aged 20 to 70 and 7 postmenopausal women aged 70 or under.
The primary outcome was met: glucose responses over 0 to 15 and 0 to 30 minutes (p < 0.001) and 0 to 45 minutes (p < 0.01) were lower after the high-PGA natto meal, and insulin responses were lower within the first hour. The authors note the mechanism is unclear and the group was mostly men from one area. Single meals only.
Randomized trial with four groups matched for age and parity: no natto, or natto at lunch once a month, once a week or three times a week, for 1 year; heel bone stiffness index by quantitative ultrasound and bone turnover markers at baseline, 6 months and 1 year (Katsuyama et al. 2004, J Nutr Sci Vitaminol (Tokyo))
73 healthy premenopausal Japanese women.
The stiffness index did not differ between groups over the year. Bone-specific alkaline phosphatase, a bone formation marker, was higher in the three-times-a-week group than in the once-a-week group at 1 year, and undercarboxylated osteocalcin was lower in that group than in all others at 6 months.
Randomized, double-blind, placebo-controlled multicenter trial; 360 mcg of MK-7 a day in the form of natto capsules versus identical olive oil placebo capsules for 12 months; primary outcome bone mineral density by DXA; registered NCT00290212; funded by the Norwegian Osteoporosis Association and Northern Norway Regional Health Authorities, with the study capsules provided by NATURAL per the article page; the abstract does not say whether the capsules held natto powder or an MK-7 extract (Emaus et al. 2010, Osteoporos Int)
334 healthy Norwegian women aged 50 to 60, 1 to 5 years after menopause, recruited.
The primary outcome was not met: after 12 months, bone loss rates did not differ from placebo at the total hip, femoral neck, lumbar spine or total body. Carboxylated osteocalcin rose and undercarboxylated osteocalcin fell versus placebo (p < 0.001).
Sequential feeding study without randomization or placebo; natto with 775, 1,298 or 1,765 mcg of MK-7 per 100 g given at 7-day intervals, plus a cross-sectional comparison by habitual natto intake; first author from the Central Research Institute of the Mitsukan Group, a natto maker (Tsukamoto et al. 2000, J Bone Miner Metab)
8 healthy male volunteers in the feeding study; 134 healthy adults in the comparison (the abstract lists 85 men and 39 women, which sums to 124).
Serum MK-7 and gamma-carboxylated osteocalcin rose with the two MK-7 enriched natto types, and undercarboxylated osteocalcin fell with the highest one. In the comparison, men who ate regular natto occasionally or frequently had higher serum MK-7 and carboxylated osteocalcin than men who ate none. Blood markers only.
Open (unblinded) study; participants randomly divided into a group taking three Sonomono Natto Powder Capsules a day (1,140 mg of freeze-dried natto with about 1.8 x 10^10 CFU of B. subtilis var. natto spores) and a group taking nothing, for 62 days; stool 16S rRNA sequencing; no external funding; several authors are employees or officers of the product maker or the analysis company (Kono et al. 2022, Nutrients)
205 residents of one Japanese town enrolled; 116 analyzed (30 men and 23 women taking capsules, 29 men and 34 women in the control group).
Bifidobacterium rose from day 0 to day 62 in men and women taking the capsules, and Blautia rose in men; several other genera shifted similarly in the control group. Most comparisons were within groups, with no placebo. Bowel habits did not change in either sex. Men taking the capsules had a significant rise in body weight and BMI, which the authors judged within an appropriate range.
Feeding study in volunteers (number not given in the abstract) comparing untreated natto with natto treated by one of five cooking methods, chosen to lower live bacteria; plasma vitamin K measured at 5, 8, 24 and 48 hours (Homma et al. 2006, J Nutr Sci Vitaminol (Tokyo))
Volunteers; the study aimed at a natto preparation suitable for people taking warfarin.
Untreated natto raised plasma MK-7 from 1.86 to 14.54 ng/mL at 5 hours, and it stayed raised at 48 hours (5.37 ng/mL). Boiling cut live B. subtilis from 9.7 to 5.1 log CFU and MK-7 content from about 660 to 79 ng/mL, and boiled natto raised plasma MK-7 only from 1.61 to 4.02 ng/mL. INR was not reported in the abstract.
Side effects and drug interactions
Common Potential side effects
Important Drug interactions
Frequently asked questions about Natto (Fermented Soybeans, Bacillus subtilis var. natto)
What is natto and what does it contain?
Natto is whole soybeans fermented with Bacillus subtilis var. natto, a sticky Japanese food usually sold in packs of about 40 g. It is one of the richest food sources of vitamin K2 as MK-7, with regular natto measured at about 775 mcg per 100 g. It also contains the enzyme nattokinase, soy isoflavones, poly-gamma-glutamic acid and live Bacillus bacteria.
How much vitamin K2 is in natto powder capsules compared with fresh natto?
It varies widely by product. One cohort study estimated about 380 mcg of vitamin K2 per pack of fresh natto. One dried natto capsule product lists 81 mcg of MK-7 per three-capsule serving, while one freeze-dried natto lists 687 mcg per 20 g serving. Check the MK-7 amount on the label; these are maker figures, not independent tests.
Can I eat natto if I take warfarin?
Not without your prescriber's approval. Japanese patient information for warfarin tells patients to refrain from natto because its vitamin K can weaken the drug, and one serving raised blood MK-7 for at least 2 days. Natto products may also contain nattokinase. Talk to the clinic that manages your dose before eating natto or taking natto products.
Does natto support bone health?
Eating natto raises blood MK-7 and activates osteocalcin, and Japanese cohort studies link habitual natto intake with less bone loss and fewer fractures. Those studies are observational. The two randomized trials, one of natto at lunch and one of natto capsules with 360 mcg of MK-7 a day, did not change bone density or stiffness over a year.
Can natto cause an allergic reaction?
Yes. Besides soy allergy, natto can cause a delayed reaction, with hives, breathing difficulty or collapse starting several hours after eating. The polymer poly-gamma-glutamic acid has been identified as an allergen, and sensitization has been strongly linked with surfing. Seek emergency care for any severe reaction, even hours after a meal.
What is Natto?
Natto is a traditional Japanese food of whole soybeans fermented with Bacillus subtilis var. natto. It is a rich food source of vitamin K2 as menaquinone-7 (MK-7), and it also carries the enzyme nattokinase, soy isoflavones, the sticky polymer poly-gamma-glutamic acid and live Bacillus spores.
What is Natto used for?
NutraSmarts does not list Natto under a health category. What the research covers: In two small randomized crossover meal tests in Japanese adults without diabetes, adding 40 g of natto rich in poly-gamma-glutamic acid to white rice lowered the glucose rise over the first 30 to 45 minutes compared with natto low in this p…
What is the recommended dosage of Natto?
The clinically studied dose is 40 g of natto with a white rice meal (single-meal glucose tests); natto at lunch up to three times a week for 1 year; 1,140 mg of natto powder (three 380 mg capsules) a day for 62 days; natto capsules supplying 360 mcg of MK-7 a day for 1 year. Always follow the product label and check with a healthcare provider for personal advice.
Is Natto safe, and does it have side effects?
Side effects and cautions reported for Natto include: Natto can cause a delayed allergic reaction: in a clinical review of 7 patients, generalized hives and breathing difficulty began 5 to 14 hours after eating natto, and 5 lost consciousness. It may also interact with some medications. Natto is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.
Does Natto interact with any medications?
Possible interactions include: Warfarin and other vitamin K antagonists: the Japanese patient drug information sheet for warfarin says that foods rich in vitamin K such as natto, chlorella and green juice (aojiru) may weaken the medicine and tells patients to refrain from them. If you take prescription medication, check with a pharmacist or doctor before using it.
How strong is the scientific evidence for Natto?
NutraSmarts rates the evidence for Natto as Limited (2 out of 5). It is backed by 7 study summaries and 16 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.
References(16 citations)
Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.
- The Possibility of Suppression of Increased Postprandial Blood Glucose Levels by Gamma-Polyglutamic Acid-Rich Natto in the Early Phase after Eating: A Randomized Crossover Pilot Study. Nutrients. 2020;12(4):915. doi: 10.3390/nu12040915.PubMedUsed to support: Randomized crossover pilot meal test in 21 healthy adults (20 completed): white rice alone, rice plus 40 g low poly-gamma-glutamic acid natto, or rice plus 40 g high poly-gamma-glutamic acid natto (both from Takano Foods). The primary outcome, glucose area under the curve over 0 to 120 minutes, was 20.1 percent lower after the high-PGA meal and 15.4 percent lower after the low-PGA meal than after rice, significant only for high-PGA (p < 0.05); early responses (0 to 45 minutes) were lower with high-PGA than low-PGA natto. The authors call it exploratory, with no adjustment for multiple tests. Registered UMIN000030182; funded by the Japanese Ministry of Agriculture, Forestry and Fisheries; no conflicts declared. The full text notes that soybeans contain water-soluble fiber, soy protein and isoflavones, and that blinding may have been incomplete because the natto types differed in texture and flavor.
- Gamma-Polyglutamic Acid-Rich Natto Suppresses Postprandial Blood Glucose Response in the Early Phase after Meals: A Randomized Crossover Study. Nutrients. 2020;12(8):2374. doi: 10.3390/nu12082374.PubMedUsed to support: Randomized crossover meal test in 36 adults without diabetes (29 men aged 20 to 70, 7 postmenopausal women) selected for relatively high glucose after rice. White rice with 40 g natto containing 439.6 mg (high) or 57.6 mg (low) poly-gamma-glutamic acid. The primary outcome, glucose area under the curve 0 to 30 minutes, was lower with high-PGA natto, as were 0 to 15 minute (p < 0.001) and 0 to 45 minute (p < 0.01) glucose and insulin within 1 hour. The authors propose a viscosity effect similar to beta-glucan but state the mechanism remains unclear. Registered UMIN000037449; funded by the Japanese Ministry of Agriculture, Forestry and Fisheries; no conflicts declared.
- Promotion of bone formation by fermented soybean (Natto) intake in premenopausal women. J Nutr Sci Vitaminol (Tokyo). 2004;50(2):114-20. doi: 10.3177/jnsv.50.114.PubMedUsed to support: Randomized trial in 73 healthy premenopausal women split into four groups: no natto, or natto at lunch once a month, once a week or three times a week, for 1 year. The ultrasound stiffness index did not differ between groups. Bone-specific alkaline phosphatase was higher in the three-times-a-week group than the once-a-week group at 1 year, and undercarboxylated osteocalcin was lower in that group than in the other three at 6 months.
- Vitamin K2 supplementation does not influence bone loss in early menopausal women: a randomised double-blind placebo-controlled trial. Osteoporos Int. 2010;21(10):1731-40. doi: 10.1007/s00198-009-1126-4.PubMedUsed to support: Randomized, double-blind, placebo-controlled trial in 334 healthy Norwegian women aged 50 to 60, 1 to 5 years after menopause: 360 mcg of MK-7 a day in the form of natto capsules or identical olive oil placebo capsules for 12 months. Bone loss did not differ from placebo at the total hip or any other site; carboxylated osteocalcin rose and undercarboxylated osteocalcin fell (p < 0.001). Registered NCT00290212, which lists the intervention as natto capsules with 360 mcg vitamin K2 a day and bone density as the primary outcome. The article page states funding from the Norwegian Osteoporosis Association and Northern Norway Regional Health Authorities and that NATURAL provided the study medication. Neither the abstract nor the article page says whether the capsules contained natto powder or an MK-7 extract; the full methods are paywalled and were not read.
- Intake of fermented soybean (natto) increases circulating vitamin K2 (menaquinone-7) and gamma-carboxylated osteocalcin concentration in normal individuals. J Bone Miner Metab. 2000;18(4):216-22. doi: 10.1007/s007740070023.PubMedUsed to support: Eight healthy men ate regular natto (775 mcg MK-7 per 100 g) and two MK-7 enriched natto types (1,298 and 1,765 mcg per 100 g) at 7-day intervals; serum MK-7 and gamma-carboxylated osteocalcin rose with the enriched types and undercarboxylated osteocalcin fell with the highest. In 134 healthy adults, men eating regular natto occasionally or frequently had higher serum MK-7 and carboxylated osteocalcin than non-eaters. First author from the Central Research Institute of the Mitsukan Group. Blood markers only.
- Fluctuations in Intestinal Microbiota Following Ingestion of Natto Powder Containing Bacillus subtilis var. natto SONOMONO Spores: Considerations Using a Large-Scale Intestinal Microflora Database. Nutrients. 2022;14(18):3839. doi: 10.3390/nu14183839.PubMedUsed to support: Open study (full text read): 205 residents of one Japanese town randomly divided into a group taking three Sonomono Natto Powder Capsules a day (each 380 mg of freeze-dried natto powder; 1,140 mg and about 1.8 x 10^10 CFU of B. subtilis var. natto spores a day) or no product, for 62 days; 116 analyzed. Bifidobacterium rose in men and women taking the capsules and Blautia in men, mostly as within-group changes, while some genera shifted similarly in controls. Men taking capsules had a significant rise in weight and BMI judged within an appropriate range. Bowel habits did not change. No external funding; authors include the president and a part-time employee of the product maker and the president and employees of the analysis company.
- Treatment of natto, a fermented soybean preparation, to prevent excessive plasma vitamin K concentrations in patients taking warfarin. J Nutr Sci Vitaminol (Tokyo). 2006;52(5):297-301. doi: 10.3177/jnsv.52.297.PubMedUsed to support: Natto contained 9.7 log CFU of B. subtilis per gram. Boiling cut that to 5.1 log CFU and cut MK-7 from 660.40 to 78.50 ng/mL. In volunteers, untreated natto raised plasma MK-7 from 1.86 to 14.54 ng/mL at 5 hours, still 5.37 ng/mL at 48 hours, while boiled natto raised it only from 1.61 to 4.02 ng/mL. The authors suggest warfarin patients may be able to eat boiled natto; INR was not reported in the abstract.
- Intake of fermented soybeans, natto, is associated with reduced bone loss in postmenopausal women: Japanese Population-Based Osteoporosis (JPOS) Study. J Nutr. 2006;136(5):1323-8. doi: 10.1093/jn/136.5.1323.PubMedUsed to support: Observational cohort study (not a trial) of 944 Japanese women aged 20 to 79 with natto intake by food questionnaire and bone density measured 3 years apart. In postmenopausal women, higher natto intake was associated with higher baseline total hip density and with smaller bone loss at the femoral neck and distal radius; the femoral neck association persisted after adjustment. Tofu and other soy products showed no association. The authors propose MK-7 or isoflavones as the reason.
- Natto Intake is Inversely Associated with Osteoporotic Fracture Risk in Postmenopausal Japanese Women. J Nutr. 2020;150(3):599-605. doi: 10.1093/jn/nxz292.PubMedUsed to support: Observational prospective cohort (not a trial) of 1,417 postmenopausal Japanese women followed a median 15.2 years; 172 had osteoporotic fractures. Compared with less than 1 pack (about 40 g) of natto a week, fully adjusted hazard ratios were 0.79 (95 percent CI 0.56 to 1.10) for 1 to 6 packs and 0.56 (0.32 to 0.99) for 7 or more packs a week. Tofu and other soy products showed no association. Registered UMIN000032869; an erratum was published.
- Association between vitamin K intake from fermented soybeans, natto, and bone mineral density in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study. Osteoporos Int. 2012;23(2):705-14. doi: 10.1007/s00198-011-1594-1.PubMedUsed to support: Cross-sectional observational analysis of 1,662 Japanese men aged 65 and older. Greater natto intake was associated with lower undercarboxylated osteocalcin and with higher total hip and femoral neck density, but the density association became non-significant after adjusting for undercarboxylated osteocalcin. The authors state natto contains about 20 mcg of vitamin K1 and 380 mcg of vitamin K2 per pack.
- Habitual natto intake elevates serum MK-7 levels, enhances osteocalcin carboxylation, and supports bone density: a meta-analysis of Japanese evidence. Front Nutr. 2025;12:1713726. doi: 10.3389/fnut.2025.1713726.PubMedUsed to support: Meta-analysis of six observational and quasi-experimental Japanese studies (2,327 people) comparing habitual natto eaters with low or non-consumers. Natto intake was associated with higher serum MK-7, higher osteocalcin, lower undercarboxylated osteocalcin and modestly greater bone density. The authors rate the certainty of evidence moderate for serum MK-7 and low or very low for osteocalcin and bone density, and say findings should be interpreted with caution. Pooled analysis, not a trial; no commercial conflicts declared.
- Late-onset anaphylaxis after ingestion of Bacillus Subtilis-fermented soybeans (Natto): clinical review of 7 patients. Allergol Int. 2007;56(3):257-61. doi: 10.2332/allergolint.O-06-460.PubMedUsed to support: Clinical review of 7 men aged 26 to 42 with reactions to natto: all had generalized hives and breathing difficulty, 5 lost consciousness, and symptoms began 5 to 14 hours (mean 9.6) after eating. All had positive skin prick tests with natto; oral challenge was positive in 2. The authors conclude reactions to natto are most often IgE-mediated late-onset anaphylaxis.
- Surfing as a risk factor for sensitization to poly(γ-glutamic acid) in fermented soybeans, natto, allergy. Allergol Int. 2018;67(3):341-346. doi: 10.1016/j.alit.2017.11.001.PubMedUsed to support: Identifies poly-gamma-glutamic acid as an allergen in natto that causes late-onset anaphylaxis. Among 140 food allergy outpatients, all 13 with natto allergy tested positive to poly-gamma-glutamic acid, and 92.3 percent had a marine sport hobby, mostly surfing (84.6 percent); marine sports were independently associated with sensitization. Natto consumption amount was not associated with sensitization. Jellyfish stings, which contain this polymer, are the proposed route.
- Natto intake is a risk factor of Bacillus subtilis bacteremia among children undergoing chemotherapy for childhood cancer: A case-control study. J Infect Chemother. 2023;29(3):329-332. doi: 10.1016/j.jiac.2022.12.010.PubMedUsed to support: Retrospective matched case-control study at one Tokyo children's hospital: 23 children receiving cancer chemotherapy with B. subtilis bloodstream infection and 92 matched controls. 78 percent of cases and 50 percent of controls had eaten natto in the previous 7 days; after controlling for neutropenia, natto intake was associated with B. subtilis bacteremia (odds ratio 3.3, 95 percent CI 1.1 to 9.6). Observational, in a high-risk group.
- Kusuri-no-Shiori (Drug Information Sheet): Warfarin Potassium Tablets 0.5mg "NP". Kusuri-no-Shiori, RAD-AR Council, Japan. 2014;English patient drug information sheet, published 02/2014; accessed 2026..SourceUsed to support: Not PubMed-indexed; official Japanese patient drug information sheet for warfarin (Nipro Corporation), read in English. It states that the medicine works by suppressing the function of vitamin K, and that foods and drinks containing large amounts of vitamin K, such as natto (fermented soybeans), chlorella, aojiru (green juice) and St. John's Wort, may diminish its effect, and tells patients to refrain from them. Cited for the warfarin interaction only.
- Dried natto: K2 MK-7, 120 capsules (750 mg); Freeze-dried natto: K2 MK-7, Nattokinase, 7 x 20 g (product pages). Natto.pl product information. 2026;Maker's product pages; accessed 2026..SourceUsed to support: Not PubMed-indexed; maker's product pages read online, cited for product forms and label contents only. The capsule product contains only dried organic natto and lists 81 mcg of vitamin K2 MK-7 per serving of 3 capsules (2,250 mg). The freeze-dried natto lists 687 mcg of MK-7 and 100 mg (2,000 FU) of nattokinase per 20 g serving, with no more than one 20 g package a day. Both state that they contain soy and advise people on vitamin K antagonist anticoagulants to consult their doctor (the capsule page also says people taking vitamin K antagonists should not consume it), and advise against use in pregnancy or breastfeeding; the freeze-dried product is not recommended for people with clotting disorders. Label values are the maker's and were not independently tested.