Serrapeptase

What serrapeptase is

Serrapeptase, technically serratiopeptidase, comes from the bacterium Serratia marcescens, which lives in the gut of the silkworm. It is a metalloprotease with zinc in its active site, 45 to 60 kilodaltons in size. Its job in the bacterium is breaking down protein, and in the laboratory it does the same with any substrate that fits.

Its career as a medicine began in Japan, where the enzyme was prescribed for decades against swelling and inflammation after surgery. In India, serratiopeptidase is still an approved drug today. In the EU it is considered a novel food whose safety has yet to be assessed. As a remedy for the blood vessels it has only appeared in the last few years, in the slipstream of nattokinase, which is sold with the same promise.

How it is supposed to work

The logic of the advertising is simple: an enzyme that cuts protein is supposed to break down inflamed tissue in the body, thin viscous mucus and dissolve deposits in the vessels. The first part of this chain is true, in the test tube. The second part assumes that the enzyme survives the journey there and is still active at the target site.

That is exactly where the gap lies. Serrapeptase is itself a protein and, after swallowing, ends up in stomach acid and pepsin, that is, in the environment whose job is breaking down protein. Whether active enzyme still reaches the blood afterwards has not been measured for serrapeptase. The existing studies looked at clinical endpoints, not at the route there.

What it is sold for

Three promises dominate the market: less inflammation, less mucus, clearer arteries. Only the first of these has been studied, and within a narrow frame — short term, after dental and ENT surgery, as a medicine over a few days. Use as a long-term product for the vessels or for general well-being has no study behind it. Yet that is exactly what it is sold for.

What the studies show

Systematic review 2013 — 24 studies

Bhagat and colleagues evaluated 24 clinical studies on serratiopeptidase in the International Journal of Surgery. Their verdict is clear: the evidence comes from studies with weak methodology, the claim of an effect against arteriosclerosis is anecdotal, and data on safety, tolerability and long-term use are missing. The evidence is not sufficient for use as a painkiller or as a dietary supplement.

Wisdom tooth trial 2009 — no effect

Chopra and colleagues studied 150 patients after wisdom tooth removal, randomized, double-blind and placebo-controlled. Result: no significant pain-relieving and no anti-inflammatory effect. It is the largest trial in the classic area of use, and it is negative.

Wisdom tooth trial 2021 — swelling yes, pain no

A randomized trial against placebo, in addition to paracetamol, completed 133 patients. Restricted mouth opening and swelling improved significantly; pain did not differ from placebo. This is the most nuanced result available on serrapeptase: a measurable effect on swelling, none on what bothers patients most.

The market withdrawal in 2011

The Japanese Ministry of Health required a reassessment of the product. The placebo-controlled double-blind trials that were conducted found no statistically significant difference from placebo. The manufacturer described further trials as difficult to carry out, and Takeda voluntarily withdrew the product in 2011. A supplier that decides against its own commercial interest carries more weight than any single study.

What is missing in humans

There is no human study on the effect on the arteries. Not a small one, not a methodologically weak one — none at all. The 2013 systematic review explicitly calls this claim anecdotal. Anyone who buys serrapeptase to break down deposits in the vessels is buying an idea for which nothing has ever been measured in humans.

Long-term safety is also open. The existing studies ran for days, as an accompanying treatment after surgery. What a protein-cleaving enzyme does in the body when taken daily for months or years has not been studied by anyone. Added to this is the unresolved absorption: that active enzyme reaches the blood after swallowing has not been demonstrated for serrapeptase. The product therefore lacks both — proof at the target and proof along the way.

Status, approval and legal

In the EU, serrapeptase is considered a novel food for which a safety assessment under the Novel Food Regulation would be required; no authorization exists. In India, serratiopeptidase is an approved drug; in Japan the original manufacturer withdrew its product in 2011, and in Singapore it was delisted. In Scotland, the food authority Food Standards Scotland required the withdrawal of dietary supplements containing serrapeptase as an unauthorized novel food in 2022. There is no authorized health claim on inflammation, mucus or blood vessels. The enzyme is nonetheless sold widely, mostly as a capsule and often in blends with other enzymes.

Safety

The documented risks are rare but serious. From Japan there are case reports of eosinophilic pneumonia under serrapeptase, one in an 84-year-old man and one in a 32-year-old woman, both with a positive lymphocyte transformation test. Also described are a Stevens-Johnson syndrome under the combination with diclofenac and an abscess that spread into deeper tissue layers during enzyme treatment. For bleeding under serrapeptase together with anticoagulants, by contrast, there is no documented case — that is a plausible warning, but not a finding. Systematic data on tolerability and long-term safety are missing, as the 2013 review explicitly states. This is not medical advice: anyone taking anticoagulants or facing surgery should discuss such products with their doctor.

Sources

• Bhagat et al., Int J Surg 2013
• Chopra et al., Int J Oral Maxillofac Surg 2009
• Tamimi et al., BMC Oral Health 2021
• Serratiopeptidase review, Biotechnol Rep 2020
• Sasaki et al., Nihon Kokyuki Gakkai Zasshi 2000
• Kai et al., Nihon Kokyuki Gakkai Zasshi 2009
• Moitra et al., J Clin Diagn Res 2014
• Rajaram et al., J Clin Diagn Res 2016
• Bruno and Saccoccio, Aesthetic Plast Surg 2026
• Hanif et al., J Med Life 2026