Among the most recent studies that found fish oil to have a beneficial effect on weight or fat loss, daily dosages of 300-3,000 mg have been used (27, 28).
According to the US Food and Drug Administration (FDA), the intake of omega-3 fatty acids from fish oil is considered safe if the daily dose does not exceed 3,000 mg per day (29).
However, the European Food Safety Authority (EFSA), the European equivalent of the FDA, considers a daily intake of up to 5,000 mg from dietary supplements to be safe (30).
It is good to keep in mind that omega-3 fatty acids have blood-thinning effects that can cause excessive bleeding in some people.
If you are on blood-thinning medications, speak to a doctor before adding fish oil supplements to your diet.
Also, be careful about the type of fish oil supplements you are taking. Some may contain vitamin A, which in large amounts can be toxic, especially to pregnant women and young children. Cod liver oil is an example.
Finally, pay attention to the contents of your fish oil supplements.
Unfortunately, certain types don’t contain a lot of fish oil, EPA, or DHA. To avoid these “counterfeit” products, choose a supplement that has been tested by a third party
To get the most benefit from your omega-3 supplements, choose one that is at least 50% EPA and DHA. For example, it should contain at least 500 mg of combined EPA and DHA per 1,000 mg of fish oil.
Summary: Fish oil is generally safe to consume. Take 300 to 3,000 mg per day to maximize the benefits of your supplements. If you are taking blood thinners, consult a doctor before adding fish oil supplements to your diet.