I have been taking a variety of fish oil supplements( Twinlab, Now) since 2003 and I believe, for the most part, that they were helpful, however I couldn’t say for certain. Recently I came across some information that is new to me. A website PsychEducation mentioned that if you purchase fish oil the amount of EPA should be 60 percent of the total amount of Omega-3 fatty acids per/pill. A fish oil pill with less than that percentage acts more or less like a placebo. I found it difficult to discern this from some of the brands since some don’t give you much detail.
a big review of all these studies and more suggests that the ratio of EPA to DHA (the two omega-3 fatty acids) really matters. Their analysis shows that of these two omega-3’s in each pill, at least 60% must be EPA. Less than that and it does not work better than a placebo; in fact in several studies, less than 60% EPA was worse than a placebo.
The Mayo Clinic gives fish oil a grade of C due to the fact that results of various studies have been mixed. I’m not sure if the information from this latest review has been taken into account?