Based on the best research available, you may want to consider taking fish oil if you have experienced a mild decline in brain function or been diagnosed with depression.
There could be other health reasons for you to take fish oil supplements, but these two groups of people will likely see the most benefits as far as brain and mental health are concerned.
There are no official recommendations regarding how much omega-3s from fish oil you need to take to see benefits in brain function and mental health. The amounts used in the research varied from study to study.
The US Food and Drug Administration has set a safe upper limit for the intake of omega-3 fatty acid supplements at 3,000 mg per day. The European Food Safety Authority has set their recommendation a little higher, at no more than 5,000 mg per day (23, 24).
Taking 1,000–2,000 mg of omega-3 fatty acids from fish oil daily is likely a good starting point that is well under the recommended upper limit. People with depression should choose fish oil supplements with higher amounts of EPA.
It is very important to read labels carefully when evaluating fish oil supplements. A 1,000-mg capsule of fish oil might contain less than 500 mg of actual omega-3 fatty acids, but this will vary from brand to brand.
In general, fish oil supplements are considered safe at dosages under those that were mentioned previously.
However, as always, you should inform your physician before starting fish oil supplements. Because of their potential effects on blood clotting, this is especially important if you are currently taking blood-thinning medications or have an upcoming surgery.
Summary People with depression or a mild decline in brain function could consider taking 1,000–2,000 mg of omega-3s from fish oil daily. Because fish oil supplements can affect blood clotting, talk to your doctor before you start taking them.