Serrapeptase

Serrapeptase is a proteolytic enzyme, meaning it breaks down proteins, produced by bacteria of the genus Serratia ^[1]. It was first isolated in the late 1960s from the intestine of the silkworm, Bombyx mori, where the enzyme naturally digests the silk of the cocoon so the adult moth can emerge, and it is now manufactured through bacterial fermentation ^[1]. Chemically it belongs to a family of metalloproteases ^[1].

For decades serrapeptase has been used, particularly in Japan and some European countries, as an anti-inflammatory and pain-relieving agent, prescribed after surgery and dental procedures and for conditions involving swelling, and it has also been promoted for clearing mucus in respiratory conditions ^[2]. Advocates additionally claim benefits for cardiovascular health based on its supposed ability to break down fibrin and other proteins ^[1].

The clinical evidence, however, is weak. A systematic review of the published literature concluded that the studies supporting serrapeptase as an anti-inflammatory and analgesic agent are few, small, and generally of poor methodological quality, and that data on its long-term safety are lacking ^[2]. Because of this, serrapeptase is regarded as having insufficient high-quality evidence to establish that it works, and in some places regulatory support for its medical use has been withdrawn ^[2]. Interest in proteolytic enzymes as anti-inflammatory agents nonetheless continues in the broader research literature ^[3].

Proposed mechanisms center on the enzyme's ability to digest proteins. It is thought to reduce inflammation and swelling by breaking down inflammatory mediators and tissue debris, to thin mucus and other secretions by cleaving their protein components, and to have fibrinolytic, or clot-dissolving, activity ^[1][3]. These properties are plausible in the laboratory, but how much intact, active enzyme actually reaches the tissues after oral dosing is uncertain ^[1][2].

Serrapeptase is sold as enteric-coated tablets and capsules, a coating intended to protect the enzyme from stomach acid so it can be absorbed in the intestine ^[1]. It is marketed as a dietary supplement in the United States and is not approved as a drug by the Food and Drug Administration ^[2]. Reported side effects are generally mild and include gastrointestinal upset, nausea, and skin reactions, though rare lung and other reactions have been described, and its protein-digesting and fibrinolytic activity means it could in theory add to bleeding risk ^[2].

Generally well tolerated; reported side effects include GI upset, nausea, skin reactions, and rare cough or lung issues. Because it breaks down fibrin, it may add to bleeding risk with blood thinners or before surgery. People on anticoagulants or with clotting disorders should be cautious.