I think its supposed to up your good cholesterol. Anyway I take 2 capsules a day, I think 'Nature Made' from Walgreens, I get them when its buy one get one free. I think the worry some people have is the heavy metal levels in the fish its derived from and that it would be even more concentrated in the oil. I would think there are regulations. I take it for cholesterol and my heart..Dr recommended it. I think the more expensive ones claim you won't burp "fish". I only do that every once in a while, certainly not often enough to justify the extra expense. :-D :-D