Fish oil supplements are a rich source of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), two types of omega-3 fatty acids.

These fatty acids have been linked with many health benefits, including improved brain health ().

DHA plays a vital role in maintaining the structure and function of your brain. In fact, it accounts for around 25% of the total fat, and 90% of the omega-3 fat, found in your brain cells (, ).

The other omega-3 fatty acid in fish oil, EPA, has anti-inflammatory effects that may protect the brain against damage and aging ().

Taking DHA supplements has been linked with improved thinking skills, memory and reaction times in healthy people who have low DHA intakes. It has also benefitted people experiencing a mild decline in brain function (, , ).

Unlike DHA, EPA isn’t always linked with improved brain function. However, in people with depression, it has been associated with benefits like improved mood (, , , , ).

Taking fish oil, which contains both these fats, has been shown to help reduce the decline in brain function associated with aging (, , , , ).

However, evidence for fish oil’s preservative effects on brain health is mixed (, ).

Overall, the best way to get the recommended amount of omega-3 fatty acids is by eating two portions of oily fish per week (20).

If you can’t manage this, then taking a supplement could be beneficial. You can find many supplements online.

More research is required to find out how much and what ratios of EPA and DHA are beneficial. But taking 1 gram per day of combined DHA and EPA is generally recommended to maintain brain health ().