You can take fish oil at any time of day, depending on when it works best for you.

This is because most research suggests that the potential benefits of fish oil supplements are not immediate, but instead associated with long-term use (2Trusted Source).

Studies show that taking fish oil over several weeks, months, or even years can increase levels of omega-3 fatty acids in the blood

However, adjusting the timing of supplementation can help prevent some of the side effects linked to fish oil.

Acid reflux, for instance, is one of the most common side effects associated with fish oil supplements.

While this could be due to the fat content of fish oil, the ingested oil floating on top of the stomach contents likely contributes to this side effect

Splitting your fish oil into two smaller doses and taking it in the morning and at night is an effective strategy that can help prevent acid reflux and indigestion

SUMMARYBecause most of the benefits of fish oil are associated with long-term use, you can take it at any time of day. That said, splitting your supplement into two smaller doses in the morning and at night can reduce acid reflux.