Effective to :

High levels of fats called triglycerides in the blood (hypertriglyceridemia).
Most research shows that fish oil can reduce triglyceride levels by 20% to 50%. The effects of fish oil are greater in people with higher triglyceride levels. Also, taking larger amounts of fish oil result reduce triglyceride levels by a greater amount. But fish oil seems to have a smaller effect compared to drugs called fibrates. Certain fish oil preparations, including Lovaza, Omtryg, and Epanova, are approved as prescription drugs for treating very high triglyceride levels. These products are most often taken at a dose of 4 grams daily. This provides about 3.5 grams of omega-3 fatty acids per day. While some non-prescription fish oil supplements have also shown benefit in research, some experts discourage people from using these products. Often these products contain less omega-3 fatty acids than the prescription fish oil products. As a result, people would need to take as many as 12 capsules per day of fish oil supplements to get the same effect as prescription fish oil. Fish oil supplements don't seem to lower triglycerides in children and teens with high triglyceride levels. But these studies were small, so larger higher quality studies are needed to confirm.