The habitual overdosing of omega-3 can cause side effects.
Too much omega-3 can cause negative side effects. For those with diabetes and heart disease, ingesting doses in excess of 3 grams per day over an extended period have been reported to elevate cholesterol levels and raise blood sugar.
Additional side effects of habitually ingesting high doses in excess of 3 grams per day can inhibit blood clotting, which increases the chance of bleeding. It can also inhibit the immune system's ability to fight off infection and can raise the body's LDL levels.
Omega-3 may increase the symptoms of certain conditions such as bipolar disorder or depression. It can also be problematic for those with liver disease, causing an increased risk of bleeding. There is some concern that omega-3 could cause blood pressure to drop too low for on blood pressure medication.