Omega XL combines a variety of fish oils with perna canaliculus oil. Omega-3 fatty acids are used in the treatment and prevention of countless conditions from high blood pressure and high cholesterol to asthma and inflammation. There are no known serious side effects to taking Omega-3 supplements.
Reported cases are usually mild, but fish oils can cause an upset stomach or nausea according to the NYU Langone Medical Center analysis. Loose stool is another gastric side effect experienced by people with more sensitive stomachs.
Bad Taste in the Mouth
Participants in both the control group and the placebo group of a clinical trial published in the 2002 European Respiratory Journal complained of a metallic taste in the mouth. This is consistent with other findings that confirm that fish oil does indeed taste like fish oil.
People with shellfish allergies may take fish oil supplements but should avoid Omega XL because of the perna canaliculus oil. It is also an Omega-3 fatty acid, but it is extracted from the New Zealand green-lipped mussel.