We are using cookies to give you the best experience on our site. Cookies are files stored in your browser and are used by most websites to help personalise your web experience.

By continuing to use our website without changing the settings, you are agreeing to our use of cookies.

Find out more
For more information, go to

Fish oil

Back to Tips on complemetary medicines

Side-effects of fish liver oil

I've been taking a fish oil supplement for about 15 years, the last 10 as liquid, as it's better value. But in my experience I'd urge caution with the recommended dose of a 5 ml teaspoon.

Several years ago I saw the results of a study which appeared to show a beneficial effect up to a certain dose and then showed less efficacy as the dose increased. It maybe should have rung alarm bells, but I ignored it.

Two years ago I developed a heart arrhythmia, which I was told was normal for my age (65) and to get on with life. I went back twice more as it became more pronounced but was assured it was ok. I did the usual research to try to find an answer as in my mind I remained unconvinced.

Ten months ago I saw the results of an American study that indicated fish oil in larger doses could cause a range of symptoms which included heart arrhythmia and prostate cancer. I stopped the fish oil supplement and within a week it was improving and after a month it was back to normal and has been since then.

I haven't had the courage to return to a lower dose but will do eventually.
Stuart Cleverley, via email

Fish oil is cheaper by the spoon 

In Arthritis Today Spring 2014, you recommend taking 'one or two fish oil capsules daily' instead of oily fish. I'd like to point out that it's much less expensive to take the oil by the spoonful from a bottle, rather than taking the capsules.
Helen High, via email

Back to Tips on complemetary medicines

Arthritis Today magazine

Anne in her garden

Read our online magazine for news on the latest research breakthroughs, treatments and education.

Search arthritis information

For more information, go to or call 0300 790 0400 to order the complete printed booklet.
Arthritis Research UK fund research into the cause, treatment and cure of arthritis. You can support Arthritis Research UK by volunteering, donating or visiting our shops.