Will omega 3 cause acne?

Omega-3 supplements may worsen acne in some people, although there is limited research on this topic. Taking omega-3 in the form of fish oil can also cause mild (though rare) side effects. Basically, fish oil supplements are very likely to cause inflammatory acne if the supplements are rancid or oxidized. You might be surprised to learn that an extremely high percentage of omega-3 supplements, including fish oil and cod liver oil, are actually stale.