Krill oil, a supplement high in omega-3, is sourced from small, shrimp-like crustaceans known as krill. Although the harvesting of krill has been around since the 1800s, krill oil has only recently become popular. It is commonly used to address various health concerns, such as supporting heart, brain, immune system, and skin health. Krill oil is deemed to be more easily absorbed and potentially more effective than traditional fish oil supplements, as it contains astaxanthin, a powerful naturally occurring antioxidant.