A major complaint of taking fish oil is flavor and “fishy burps,” but a high-quality fish oil should not have a “fishy” aftertaste, Bland says.
Ferira couldn't agree more, adding that "fish oil shouldn't make you burp…that's not a good sign of the quality of the oil." What's more, as she previously shared on the mindbodygreen podcast, "If your fish oil smells funny—fishy, sour, or it's very yellow—these are signs of bad purity. It's a sign of oxidation."
As far as side effects go, “There are no serious side effects from taking a lot of fish oil other than mild gastrointestinal concerns at high doses,” Bland says.
However, out of an abundance of caution, people who are taking blood-thinning medications or who have specific health concerns related to bleeding should consult their doctor before taking fish oil to make sure their dosage doesn’t interfere with their medications, Bland notes. That's because omega-3s can impact platelet activity.*
So what does this omega-3 and platelet relationship mean for everyday use of fish oil? "In reality, the blood-thinning effect of fish oil actually occurs at absurdly high levels of EPA plus DHA, 10 grams plus, which by the way, no supplement even comes close to containing," Ferira previously shared with mbg.
That's a very important dose distinction, since in fact, "omega-3 supplements are playing in the 200- to 1,800-milligram range of EPA plus DHA 99% of the time," Ferira adds. In other words, the blood-thinning consideration level for most people is up to 20 times the typical daily dose of a fish oil supplement (so the average person shouldn't be concerned).
For a full explainer on the potential side effects of fish oil, you'll want to check out this full explainer.