Serrapeptase: What Human Trials Show on Swelling, Sinuses and Safety

Quick answer. Serrapeptase (serratiopeptidase) is a protein-digesting enzyme made by Serratia bacteria and sold in the U.S. as a supplement. Most human studies are small, short trials of 10 to 30 mg a day after dental, sinus or ankle surgery or for ear, nose and throat complaints; several found less swelling than placebo, others found no benefit, and steroids usually did as well or better. In 2011 Takeda withdrew it as a medicine in Japan after its own placebo-controlled trials were negative, and other makers followed. We found no human trial behind claims about scar tissue, arterial plaque or blocked fallopian tubes. Case reports describe lung inflammation and severe skin reactions, and Health Canada advises asking a practitioner first if you take blood thinners, are pregnant or breastfeeding, or are having surgery.

What serrapeptase is

Serrapeptase is also called serratiopeptidase, Serratia peptidase or serrapeptidase. Health Canada lists its source as Serratia marcescens strain E-15, which research papers link to the silkworm gut, and it is produced by fermentation. It is a protein-digesting enzyme of about 50 kDa that reviews describe as fibrinolytic, able to break down fibrin, the mesh that holds blood clots together. We found no study measuring this in people, and in one rat study swallowed serrapeptase dampened rather than raised clot breakdown after burns. It was a medicine in Japan until 2011 and in Singapore until 2012 (see below). Health Canada licenses it as a natural health product. In 2022 Food Standards Scotland called it an unauthorized novel food and advised that supplements containing it be withdrawn.

Units cause confusion. Trials report milligrams, usually from 5 or 10 mg tablets, while labels list activity units, often "SPU." Health Canada uses "serratiopeptidase units (SU)," measured with the Japanese Pharmacopoeia assay, and gives no milligram conversion. We found no official document showing that SPU and SU are the same.

What human studies have tested

We found about two dozen human studies in PubMed of serrapeptase alone or against another treatment. Six compared it with a placebo; the largest enrolled 193 people. The table shows the key studies.

What the findings suggest

Swelling after dental and sinus surgery. Placebo-controlled trials after sinus surgery and wisdom tooth removal found less swelling, but a 2009 trial of 150 patients found no significant benefit. Pain results were mixed: one small trial found less pain, two did not. In five further studies against a steroid, the steroid did as well or better on swelling in four; in the fifth, serrapeptase did better on swelling and the steroid on pain. A 2018 meta-analysis found better mouth opening than with corticosteroids but no difference in swelling. Health Canada lets licensed products say they help reduce cheek swelling or pain after dental surgery. Evidence strength: limited and mixed, from small trials of about a week or less.

Ear, nose, throat and airways. A 1990 trial in 193 people found faster symptom relief than placebo, and small Japanese studies found thinner nasal mucus or sputum after 4 weeks at 30 mg a day, but Takeda's placebo-controlled chronic bronchitis trial was negative. Evidence strength: limited and conflicting.

Breast engorgement. One 1989 trial in 70 women favored serrapeptase; a 2020 Cochrane review judged that it may reduce engorgement, with low-certainty evidence, and was uncertain about pain and swelling. Evidence strength: limited.

Sprains and injuries. A small 1989 trial after ankle surgery and a non-randomized 2024 sprain study reported less swelling, and a 2026 observational study lower pain scores, but Takeda's placebo-controlled ankle sprain trial was negative. Evidence strength: low.

Scar tissue, plaque and fallopian tubes. We found no human trial that measured scar tissue. The one study of scar-like fibrosis after surgery, in 50 women after liposuction, found no difference at 60,000 IU a day for 4 weeks. A PubMed search pairing serrapeptase with fallopian tubes, fertility, endometriosis or fibroids found nothing. A 2013 systematic review said claims of anti-atherosclerotic effects rest on anecdotal reports, and we found no human or animal study of arterial plaque. Evidence strength: none in humans.

Where the evidence is limited or conflicting

• Old, small and short. Most trials enrolled under 200 people, lasted days, and measured swelling with tape or calipers; many patients also took painkillers or antibiotics. A 2013 systematic review of 24 clinical studies called their methods poor and the evidence insufficient to support use as a pain reliever or health supplement.
• Unpublished negative trials. Takeda's 2011 recall notice, posted in the Japanese health ministry's recall database, says its post-marketing trials in chronic bronchitis and ankle sprain did not beat placebo and a repeat trial was judged not feasible; the recall was not due to a quality problem, and other makers recalled their tablets that week for the same reason. Singapore's Health Sciences Authority then found "no substantive scientific evidence to support the classification of serratiopeptidase as a medicinal product," while still allowing it in health supplements. We did not find the Japanese trials in PubMed.
• Absorption is shown only in rats. At a high oral dose (100 mg/kg), serrapeptase reached rat blood in active form, peaking 30 minutes to 2 hours later. In rat blood, and in test tubes with the purified human protein, it binds alpha-macroglobulin, which lowers its activity (rat blood kept about 20%). Formulation studies describe it as acid-sensitive, which is why it is usually given in enteric-coated tablets. We found no human study with an abstract measuring how much reaches the blood. Animal results also conflict: one rat study found anti-inflammatory effects; another, using oral doses, found none.
• Funding. The 2021 placebo-controlled trial was fully funded by Hayat Pharmaceutical, its registered sponsor. Its registry entry names a 5 mg tablet and 112 participants; the paper reports 10 mg three times daily in 140 people. The 1989 engorgement trial used Takeda's tablets, and Takeda researchers ran the rat absorption study. Two co-authors of the 2026 orthopedic study of a branded tablet list Helix Pharma's medical affairs department as their affiliation; we found no funding statement.

What buyers say, and what the research shows

Our team analyzed 1,063 public Amazon reviews of 11 enzyme products, collected in September 2026. Eight contain serrapeptase, always with nattokinase and sometimes lumbrokinase; one of the eight is Vinatura's, and the figures below describe the 7 others. Figures are approximate shares of reviews mentioning a theme, found by keyword matching and weighted toward reviews shoppers voted helpful. Reviews show what buyers believe or report; they cannot show whether a product caused any change, or, for blends, what serrapeptase did on its own.

Belief: it eases pain and inflammation and breaks down scar tissue. Pain, inflammation or scar tissue came up in at least 10% of positive-review weight on 4 of the 7 other serrapeptase products, and 32% of weighted reviews of the longest-listed one named it as a reason for buying. It came up just as often on 3 lumbrokinase-only products, which contain no serrapeptase. Trials support, at most, a short-term effect on swelling, and in some trials pain, after surgery, and the one study of post-surgical fibrosis found no effect.

Belief: an enzyme must be enteric-coated to work. Complaints that a capsule was not enteric-coated or delayed-release reached at least 10% of critical-review weight on 2 of the 10 other products. Formulation studies describe serrapeptase as acid-sensitive, and Health Canada accepts only enteric-coated or delayed-release forms, but we found no human study comparing coated with uncoated forms.

Belief: it is gentle, with no side effects. Praise for being gentle or free of side effects reached at least 10% of positive weight on 4 of the 7, while stomach-upset complaints reached that level of critical weight on 2. Trials were too short to judge long-term safety, and serious reactions have been reported.

Safety

In trials. Most trials lasted days and reported few or mild side effects, or none. In the 2026 orthopedic study, stomach upset (2.8% vs 3.3%) and rash (1.2% vs 1.4%) were about as common with serrapeptase as without. The 2013 systematic review found safety data lacking and no long-term data. Singapore's regulator cited a long history of use with minimal safety concerns.

Case reports. Japanese reports describe lung inflammation (pneumonitis or eosinophilic pneumonia) in men aged 69 and 84, after 16 days and 3 months, and in a 32-year-old woman 3 days after starting it; the men improved after stopping it or with steroids. Other reports describe a blistering skin disease, Stevens-Johnson syndrome after a diclofenac-serratiopeptidase combination, and a facial abscess that spread after serratiopeptidase; its authors advised limiting use when an abscess is present. A man who injected an oral serrapeptase-nattokinase supplement into a vein needed an arm amputation. Case reports cannot prove cause. NIH's LiverTox database, which covers liver injury from drugs and supplements, has no entry on serrapeptase.

Who should be careful. Health Canada's 2025 monograph tells users to ask a health care practitioner before use if they are pregnant or breastfeeding, have stomach or intestinal lesions or ulcers or a kidney or liver disorder, are having surgery, or take blood thinners or anti-inflammatory medicines, and to stop if rash, difficulty breathing or a severe allergy occurs. It asks for a practitioner's advice before using swelling-and-pain products, or more than 60,000 SU a day, beyond 7 days, and lower-dose products beyond 4 weeks. We found no safety data in pregnancy.

Interactions. We found no human study of serrapeptase with blood thinners, antiplatelet medicines or NSAIDs; the 2021 trial excluded people taking anticoagulants. In a Japanese study of 35 lung surgery patients, the lung-to-blood ratio of the antibiotic cefotiam was higher with serrapeptase (44.2% vs 29.1%). Many serrapeptase supplements are blends with nattokinase, whose bleeding and interaction risks we cover in our nattokinase review.

Upper limits. Health Canada's monograph caps licensed products at 120,000 SU a day. We found no other official upper limit.

What research does not establish

• That serrapeptase breaks down scar tissue, arterial plaque, blood clots or blocked fallopian tubes in people.
• That it relieves chronic sinus or bronchitis symptoms.
• That swallowed serrapeptase reaches human blood or tissue in active form, or that enteric coating changes how much does.
• That label amounts in SPU match the milligram doses used in trials, or that higher amounts work better.
• That it is safe for months of use, during pregnancy, before surgery, or with blood thinners or anti-inflammatory medicines.

How we reviewed the evidence

On October 25, 2026, we searched PubMed for every record mentioning serrapeptase or its other names (189) or "Serratia protease," screened about 195 by title and abstract, and ran targeted searches on trials, absorption, adverse effects, interactions, pregnancy, blends and each popular claim. We included human trials, reviews, observational studies and case reports, and used animal and lab studies only to explain absorption and mechanisms. We read PubMed Central full texts where available and abstracts otherwise (only the English abstract for older Japanese, German and Italian papers). ClinicalTrials.gov listed 8 records; 6 test serratiopeptidase, all in dentistry, and none has posted results. We read Health Canada's monograph (July 25, 2025), Japanese recall notices for serrapeptase tablets (February 2011), Singapore's Health Sciences Authority announcement (November 29, 2011) and a Food Standards Scotland enforcement letter (February 21, 2022), and checked NIH's LiverTox. Buyer beliefs come from our team's analysis of public Amazon reviews. Vinatura did not run any of these studies.

Vinatura Research Perspective

We asked four questions of each serrapeptase study: what form and dose (milligrams of a drug-grade tablet or label units of a supplement), in whom, measured how, and funded by whom. The answers showed three gaps. First, nearly every trial tested days to weeks of use after surgery or injury or for ear, nose and airway complaints; claims about scar tissue, plaque and fallopian tubes have no human trials. Second, the published record leans more positive than the regulatory one: Takeda's own placebo-controlled trials were negative and led to withdrawal in Japan, yet we could not find them in PubMed, while the most recent published placebo-controlled trial was funded by a drug company. Third, doses do not translate: trials report milligrams (one used IU, none SPU); competing products in our review sample that stated an amount listed 120,000 to 360,000 SPU per serving; and Health Canada caps licensed products at 120,000 SU a day, with no official document relating the three measures.

Our assessment: evidence for less swelling after dental and sinus surgery is limited and mixed, with steroids as good or better in most head-to-head studies; evidence for ear, nose, throat and airway symptoms and breast engorgement is limited and mostly decades old; there is no human evidence for scar tissue, plaque or fallopian tubes; and absorption in people is unproven. An independently funded, pre-registered, placebo-controlled trial of a supplement labeled in SPU, published whatever its result, would change this assessment, as would a human study measuring active enzyme in blood or publication of the Japanese trials.

Where this ingredient appears in Vinatura products

Lumbrokinase Nattokinase Serrapeptase contains 30 mg serrapeptase (60,000 SPU) per serving, with 15 mg lumbrokinase (15,000 IU/mg) and 100 mg nattokinase (2,000 FU), in one delayed-release capsule; each bottle holds 60 servings. Its current Amazon listing states that it contains soy and milk. The studies above did not test this product, and none tested serrapeptase combined with lumbrokinase and nattokinase.

Frequently asked questions

Does serrapeptase need an enteric coating? Formulation studies describe it as acid-sensitive. Health Canada accepts only enteric-coated or delayed-release forms and directs taking them 2 hours after a meal. We found no human study comparing coated and uncoated forms or testing timing with food.

How much did studies use? Most trials used 10 to 30 mg a day, often 10 mg three times daily, for days to 4 weeks. Health Canada's monograph allows 30,000 to 120,000 SU a day for swelling and pain uses, and we found no official conversion between units and milligrams. These are study and regulatory amounts, not a recommendation; follow your product label and ask a healthcare professional.

Should I stop serrapeptase before surgery or dental work? We found no study that answers this. Health Canada's monograph tells users to ask a health care practitioner before use if they are having surgery. Tell your surgeon or dentist you take it and follow their instructions.

References

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Editorial note: This article reviews published research for educational purposes. It does not establish the effects or safety of any specific supplement, including Vinatura products, and is not medical advice. Written by Vinatura Editorial Team. Last reviewed October 2026.