Antarctic krill are tiny, shrimplike crustaceans that feed on algae, accumulating long-chain EPA and DHA in the process. Because Antarctic waters are among the cleanest on earth and krill are at the bottom of the food chain, they contain fewer environmental contaminants than fish. Krill oil pills cost more and don’t contain as much EPA and DHA as a typical fish oil capsule, but krill’s omegas have a phospholipid molecular structure more similar to human cell membranes than that of fish oil—which, fans say, makes krill oil easier to digest and absorb.

Although there’s not yet enough research to prove those qualities, in a new, double-blind, randomized trial involving 300 people with borderline or high triglyceride levels, those taking 4 grams krill oil daily for 12 weeks lowered their triglycerides by 10 percent without increasing LDL (bad) cholesterol. Other benefits: “About half the people who use krill had previously taken fish oil and stopped because they had problems with fish burps,” says Adam Ismail, executive director of GOED. “They don’t have those problems with krill oil.” Krill capsules are also much smaller and easier to swallow than typical fish oil pills.

Do the oceans have enough fish to meet the demand for fish oil supplements? 

For now, yes. Ismail says roughly 80 percent of fish oil supplements are derived from anchovies (which have the highest EPA-DHA concentration of any fish) from one fishery in Peru. Currently, demand doesn’t outstrip supply. “But if the demand keeps growing the way it is, in three to four years we may reach the limits of what the anchovy fishery can provide,” Ismail says. With that in mind, companies are working on efficiencies to produce more EPA-DHA using fewer fish. Others are turning to different sources, such as krill, salmon, menhaden, and algae.