Fish oil has been studied extensively for reducing coronary heart disease, whereas few studies focus on Krill oil for heart health, according to University of Massachusetts Medical School. Fish oil studies indicate its ability to lower triglycerides, reduce inflammation and decrease risk of sudden heart failure, states Mayo Clinic.
Mayo Clinic explains that both fish oil and krill oil contain Omega-3 fatty acids called docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA, which are thought to promote heart health and reduce cholesterol. Fish oil has been studied more thoroughly in human subjects, unlike Krill oil studies conducted mostly in mice and rats, states UMASS. Fish oil has also show evidence of lowering blood pressure and triglyceride levels that promote heart health. As of 2015, Krill oil does not have the scientific studies to support heart health benefits the way that fish oil does.