Krill oil is sourced from Antarctic krill (Euphausiasuperba), a small, shrimp-like crustacean that exists in large swarms. It attains an individual maximum size of 2 inches and feeds mainly on phytoplankton or sea ice algae. Krill is the staple food of many mammals, fish and sea birds in the Southern Oceans. Krill oil is a natural source of the red carotenoid astaxanthin, which is derived from the micro-algae food source of the Antarctic krill. Astaxanthin is responsible for the red colour of krill and other crustaceans such as lobster, shrimp and salmon. Much of the commercial fish farming industry no longer use this natural carotenoid, with synthetic astaxanthin added to fish feed to improve the colour of the fish instead. Attributes of Krill Oil 1) Phospholipids & Omega-3: Krill Omega-3 fatty acids are bound to phospholipids where it is considered that they are more efficiently absorbed via the small intestines with the phospholipid complex readily absorbed into the cell membranes. Other sources of Omega-3 fatty acids are bound to triglycerides, which are insoluble and require bile salts for their emulsification and absorption via the lymphatic system. A study of the metabolic effects of krill and fish oil found comparable dietary sources of Omega-3 fatty acids when assessing plasma concentrations. 2) Phosphatidyl Choline: Krill phospholipids contain choline, an essential nutrient, and neurotransmitter precursor important to brain and muscle tissue. Phosphatidyl choline participates in fatty acid transport in the blood and across membranes. Choline intake is important, starting in early life during foetal development and continuing where a deficiency of choline is linked to areas of dysfunction, including elevated homocysteine, memory, growth and hepatic disorders. 3) Astaxanthin: Astaxanthin is a carotenoid molecule with powerful antioxidant activity found in krill oil.