Fish oilDoes fish oil contain mercury?
Updated 4 Nov 2026
Short answer
Tests have not found it. Seafood contains varying levels of methylmercury, but omega-3 supplements have not been found to contain it, because processing and purification remove it.[1] For one prescription omega-3 product, the starting oil is screened for heavy metals and PCBs.[2]
Pregnant women are advised to choose lower-mercury seafood such as salmon, anchovies, sardines, Pacific oysters and trout.[1] Dietary supplements in the US do not need extensive approval before sale, and their contents can differ from the label.[3]
Sources (3)
- Omega-3 Fatty Acids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
- Omega-3 Fatty Acids. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, 2017. PMID 31644217
- Marine Oils. Drugs and Lactation Database (LactMed®), 2026. PMID 30000958
More about fish oil
What is fish oil?Does fish oil reduce inflammation?How much EPA and DHA is in a fish oil capsule?Is eating fish better than taking fish oil?What is fish oil used for?Should fish oil be taken with food?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.