Among the most recent studies that found that fish oil had a positive effect on weight or fat loss, daily dosages of 300–3,000 mg were used (27, 28).
According to the US Food and Drug Administration (FDA), intake of fish oil omega-3s 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 daily intakes of up to 5,000 mg from supplements to be safe (30).
It’s good to keep in mind that omega-3s have blood-thinning effects that may cause excessive bleeding in some people.
If you’re taking blood-thinning medication, talk to a healthcare professional before adding fish oil supplements to your diet.
In addition, be careful with the type of fish oil supplements you take. Some may contain vitamin A, which can be toxic when taken in high amounts, especially in pregnant women and young children. Cod liver oil is one example.
And finally, make sure you pay attention to the content of your fish oil supplements.
Unfortunately, certain types actually don’t contain much fish oil, EPA or DHA. To avoid these “fake” products, pick a supplement that has been tested by a third party
To get the most benefits from your omega-3 supplements, choose one that is made up of at least 50% EPA and DHA. For instance, it should have at least 500 mg of combined EPA and DHA per 1,000 mg of fish oil.
Summary: Fish oil is generally safe to consume. To maximize the benefits of your supplements, take 300–3,000 mg per day. If you take blood thinners, check with a healthcare professional before adding fish oil supplements to your diet.