Serrapeptase
A protein-digesting enzyme originally isolated from silkworm gut bacteria, prescribed in Japan and Europe for decades as an anti-inflammatory and mucus-thinning agent, with a thin and inconsistent evidence base.
At a Glance
- Best known for
- Reduces post-surgical swelling and pain in some trials, Thins mucus in sinusitis and bronchitis, Anti-inflammatory via breakdown of inflammatory proteins
- Evidence
- Preliminary
- Typical dose
- 10 mg (20,000 SPU) 3x daily
- Type
- Compound
What is Serrapeptase?
Serrapeptase (serratiopeptidase) is a proteolytic enzyme produced by the bacterium Serratia marcescens, discovered in the 1960s in the intestine of the silkworm, where it dissolves the cocoon to let the moth emerge. Japanese researchers developed it as an anti-inflammatory drug (Danzen) in the late 1960s, and it was prescribed widely in Japan, Europe, and Asia for swelling, sinusitis, and bronchitis. Sales in Japan were suspended in 2011 after a re-evaluation trial failed to show efficacy, but the enzyme remains popular as a supplement in the West, where it is marketed for inflammation, scar tissue, sinus congestion, and cardiovascular health.
Known Health Benefits
How It Works
Serrapeptase is a broad-spectrum protease that hydrolyzes peptide bonds in proteins, with notable activity against fibrin, bradykinin, and other inflammatory mediators. By degrading bradykinin and reducing vascular permeability it is thought to reduce edema and pain. It breaks down fibrin and dead tissue, which may help clear debris from inflamed sites, and it reduces the viscosity of mucus by cleaving mucin glycoproteins, improving clearance from sinuses and airways. In vitro it degrades bacterial biofilm matrix and enhances antibiotic penetration. Claims that it dissolves arterial plaque or scar tissue in living humans rest on extrapolation from these laboratory actions; there are no human studies demonstrating such effects.
What Research Says
A 2013 systematic review in the International Journal of Surgery examined all available trials and found evidence of modest benefit for post-operative swelling, but concluded the studies were small, old, mostly of poor quality, and insufficient to support serrapeptase for any indication. Individual positive trials include a 1989 Indian study of 70 women with breast engorgement (improvement in 85% versus 60% with placebo), a 1990 study in 193 people with acute or chronic ear, nose, and throat disorders showing faster symptom relief, and several small dental surgery studies showing reduced cheek swelling and trismus after third molar extraction. A 1996 study in 20 carpal tunnel patients reported improvement in 65%. Against these, a 2011 Japanese large-scale re-evaluation found no significant benefit over placebo for post-surgical swelling, leading the manufacturer to withdraw the drug. Studies on sinusitis and bronchitis showed improved mucus clearance but were small. There are no human trials for cardiovascular plaque, scar tissue, fibroids, or chronic pain. The evidence is best described as preliminary and contradictory.
Active Compounds
Serratiopeptidase (serralysin), a zinc-dependent metalloprotease from Serratia marcescens (E15); activity measured in SPU or IU
Forms & Bioavailability
Serrapeptase is destroyed by stomach acid, so enteric coating is essential; uncoated powder is largely inactive orally. Animal studies detect the enzyme in blood and lymph after enteric oral dosing, supporting systemic absorption, though the fraction absorbed is small. It should be taken on an empty stomach (30–60 minutes before or 2 hours after food) so it is not diverted to digesting dietary protein. Potency is expressed in SPU (serratiopeptidase units) or IU; roughly 2,000 SPU per milligram is typical.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Post-surgical or injury swelling | 10 mg (20,000 SPU) 3x daily |
| Sinus congestion / bronchitis mucus | 10 mg 3x daily |
| Chronic inflammation (supplement use) | 40,000–120,000 SPU daily in divided doses |
| Breast engorgement (lactation) | 10 mg 3x daily for 3 days |
Always consult a healthcare provider for personalized dosing.
Natural Food Sources
- Not found in food; produced by bacterial fermentation
Potential Side Effects
Stomach upset, nausea, loss of appetite; skin reactions; joint and muscle pain reported rarely; rare cases of pneumonitis and Stevens-Johnson syndrome in Japanese pharmacovigilance; possible increased bleeding
Who Should Avoid It
- Anticoagulant or antiplatelet therapy (bleeding risk)
- Bleeding disorders or upcoming surgery (stop 2 weeks before)
- Pregnancy and breastfeeding (no safety data)
- Severe liver or kidney disease
- History of lung disease reactions or skin reactions to the enzyme (pneumonitis, Stevens-Johnson reported)
Pregnancy & Lactation
Avoid. No safety data exist for pregnancy, and although one older trial used it for breast engorgement, there is no information on transfer into milk or effects on the infant. Standard advice is to avoid it while breastfeeding.
Known Drug Interactions
Additive bleeding risk with anticoagulants and antiplatelets (warfarin, aspirin, clopidogrel); may increase absorption of antibiotics (used deliberately in some protocols); possible additive effects with other proteolytic enzymes
Evidence Classification
Based on in vitro studies, animal models, pilot trials, or traditional use documentation. Clinical evidence is limited.
Frequently Asked Questions
Does serrapeptase dissolve scar tissue or arterial plaque?
No human evidence supports either claim. These ideas come from the enzyme's ability to digest proteins in a test tube and from its silkworm origin. Your arteries and scars are living, structured tissue, and an oral enzyme at supplement doses does not selectively digest them. Be skeptical of marketing that promises this.
Why was it withdrawn in Japan?
Serrapeptase was sold as a prescription anti-inflammatory in Japan for 40 years. When regulators required a modern placebo-controlled re-evaluation, the trial failed to show benefit for post-surgical swelling, and the manufacturer voluntarily withdrew it in 2011. That does not prove it never works, but it is a significant negative finding against the older, weaker positive trials.
Is it useful for sinus problems?
It does thin mucus, and small trials in chronic sinusitis and bronchitis showed improved clearance and symptoms. This is probably its most plausible use. Saline rinses, steam, and treating the underlying cause remain first-line; serrapeptase can be a short-term adjunct.
How does it compare with bromelain?
Both are proteolytic enzymes used for swelling and inflammation. Bromelain comes from pineapple, has a longer safety record as a food-derived supplement, and has somewhat better trial evidence for osteoarthritis and post-surgical swelling. Serrapeptase is more potent per milligram but has the weaker and more contradictory evidence base. They are often combined.
References
- Serratiopeptidase: a systematic review of the existing evidence. Bhagat S, Agarwal M, Roy V. Int J Surg (2013)View study
- The role of serratiopeptidase in the resolution of inflammation. Tiwari M. Asian J Pharm Sci (2017)
- Serratiopeptidase: insights into the therapeutic applications. Jadhav SB, Shah N, Rathi A, Rathi V, Rathi A. Biotechnol Rep (Amst) (2020)
- Serrapeptase. Examine.comView study
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.