Turns out that most fish oil supplements are rancid. A recent study had a look at a lot of fish oil brands over a 7 year period. Nearly 70% of the flavored products had oil that was oxidized before they got to the stores. Oxidation is bad because it gives fish oil that terrible old fish smell AKA rancid.. And you’re not going to notice because it’s flavored. The found that 13% of the unflavored versions were rancid.
Also, rancid oil not only doesn’t help your body, it’s possible that it’s not good for you. One study found that people who took rancid fish oil had significant unfavorable effects on how cholesterol is distributed in the body.
What can you do? Research and find reputable companies with great reviews. Once you get some, store it in a cool place to help the shelf life. I’ll tell you this though. I used to take fish oil pills, but quit after several studies showed that it doesn’t really do anything for your heart or brain. I didn’t notice any difference from when I took them, for 2 years and when I wasn’t.