Shellfish is a traditional remedy for arthritis. The indigenous Maori population of New Zealand uses Perna canaliculus, commonly known as the green-lipped mussel, for this purpose, as explained by Drugs.com. The website notes that some studies support the effectiveness of the New Zealand green-lipped mussel extract for treating inflammatory disorders such as arthritis and asthma. Standardized preparations of this supplement are available under the brand names Lyprinol and Seatone. The green-lipped mussel naturally contains omega-3 fatty acids, which help reduce inflammation, and chondroitin sulfate, a supplement used to decrease and prevent joint pain. Research is lacking on the safety of green-lipped mussel extract, according to the American Cancer Society, but the society notes that the substance appears to be "relatively non-toxic."
Gastrointestinal Side Effects
A small number of people experience gastrointestinal effects when taking New Zealand green-lipped mussel and its extracts, according to Drugs.com. These side effects may include abdominal discomfort, gas, diarrhea and nausea.
A possible green-lipped mussel extract side effect is temporary worsening of arthritic pain, according to Drugs.com, which might last up to three days. Physician Grant Cooper, writing at HealthCentral, notes that the Australian Rheumatism Association has reported the potential side effect of gout, a very painful type of arthritis. A gout attack usually develops rapidly and tends to affect only one particular joint, often the big toe. Severe pain can last for a day or two, and lingering pain for several weeks.
Green-lipped mussel extract may cause allergic reactions in people with seafood allergies, according to the American Cancer Society. Symptoms of an allergic reaction to shellfish or other seafood may include a rash or hives, itching, skin irritation, wheezing, difficulty breathing, abdominal pain, diarrhea, nausea vomiting, dizziness, lightheadedness, fainting, and swelling of the face, tongue, throat or other parts of the body. An allergic reaction to the New Zealand green-lipped mussel should be considered a medical emergency.
One case of hepatitis has been associated with New Zealand green-lipped mussel supplements, according to Drugs.com. A woman developed granulomatous hepatitis, a nonviral type of the disease, with symptoms of jaundice, lack of appetite, malaise and abdominal pain. She recovered completely after discontinuing the supplement and all medications.