Taking 2000 mg of omega-3 fish oil daily for three months doesn't lower a common marker of body inflammation called hsCRP, no matter what your genes say. So, if omega-3s help your cholesterol, it's probably not because they're calming down inflammation.

Taking 2000 mg of omega-3s daily for three months doesn’t change your good cholesterol, total cholesterol, or inflammation markers — so if it helps lower bad cholesterol and triglycerides, it’s not because it’s reducing overall inflammation or affecting all types of fats in your blood.

Taking omega-3 supplements may help lower inflammation in your body, which you can see through blood tests that measure markers like CRP and IL-6.

People with a specific gene variation called PPARG may see much better results from taking omega-3 supplements—like lower bad cholesterol and triglycerides—than people without that gene variation.

People with heart disease who eat more omega-3s—like those found in fish—tend to have lower levels of two blood markers that show inflammation, which might mean omega-3s help calm down their body’s inflammatory response.

For middle-aged and older adults with high 'bad' cholesterol and certain gene versions, taking 2000 mg of omega-3 fish oil every day for three months can lower their bad cholesterol and triglycerides more than a placebo — and their genes might make this effect stronger.