Our Members Asked:
Is fish oil safe? Is it contaminated with mercury and PCBs?
Medically reviewed and edited by Tod Cooperman, M.D.
Answer:ConsumerLab.com's tests of fish oil supplements have found none to contain mercury and most, although not all, to have only trace levels of PCBs (which can't be fully avoided since PCBs are found in water everywhere). A serving of fish meat is likely to contain far more contamination than a fish oil supplement. However, we have found some supplements to contain less fish oil than listed and some to be spoiled. In addition, the enteric coatings on some supplements have not worked properly.
Clinical studies have shown fish oil to be safe, but it is recommended that you get no more than 2 grams (2,000 mg) of omega-3 fatty acids (EPA and DHA) from fish oil supplements per day.
For details, including our test results and comparisons of fish oil supplements and dosage recommendations, see our Fish Oil Supplements Review.
Related CL Answers (18)
Is kratom too dangerous to use?
Find out if kratom is safe/legal to use, including potential adverse effects, such as agitation, rapid heartbeat, nausea, drowsiness, seizures. ConsumerLab.com's answer explains.
What is the difference between fish oil and cod liver oil? Is one better than the other?
Find out how regular fish oil and cod liver oil differ including amounts of omega-3s EPA and DHA, vitamin A and vitamin D, which is best to suit your needs. ConsumerLab.com's answer explains.
How do fish oil supplements compare to EPA prescription fish oil like Vascepa?
How do regular fish oil supplements compare to prescription fish oil such as Vascepa and Lovaza. Info on amounts of EPA and DHA, dose, cost and absorption. ConsumerLab.com's answer explains.
Can I use a home test for mercury to check for mercury in fish, like canned tuna, fresh fish, and sushi?
Find out if home mercury test kits can be used to test fish, such as canned tuna, fresh fish or sushi for mercury contamination. Plus, find out how much mercury ConsumerLab found in popular canned tuna and canned salmon. ConsumerLab.com's answer explains.
Is DPA an important omega-3 fatty acid? It's been promoted as more "powerful" than EPA and DHA.
Find out more about DPA (docosapentaenoic acid), the third most prevalent omega-3 fatty acid in fish oil. Learn how much DPA is in supplements and fish, plus the clinical evidence for DPA, whether it can improve heart health, lower triglycerides and more. ConsumerLab.com's answer explains.
Can taking too much fish oil be dangerous?
Find out if too much fish oil can be dangerous, and if taking too much fish oil can cause effects such as suppressing the immune system, thinning the blood (increasing the risk of bleeding), increasing levels of LDL cholesterol and liver enzymes or increasing the frequency in episodes atrial fibrillation. ConsumerLab.com's answer explains.
How can I tell if my fish oil supplement is rancid (oxidized) or spoiled? And if it is spoiled, is it still safe to take?
Find out how to tell if your fish oil supplement is rancid (oxidized) or spoiled and how to store fish supplements to keep them fresh. ConsumerLab.com's answer explains.
Is it true that fish oil is better absorbed when taken with a fatty meal?
Find out if it's better to take fish oil supplements with a meal or on an empty stomach to maximize their absorption.
Is it true that fish oil supplements may contain soy? I'm allergic!
Learn about soy content in fish oil and cod liver oil, including safety for those with soy allergies.
Is echium oil a good alternative to fish oil? I am allergic to fish.
Echium oil as an alternative to fish oil. Learn more for those with fish allergies, including information on omega-3 fatty acids.
Is it true that there is no point in taking fish oil supplements for heart health?
Taking fish oil for heart health may be a benefit. Learn more about omega fatty acids from fish oil and it's impacts.ains.
Is it better to eat farmed salmon or wild salmon? Which one has more omega-3s and less contamination with PCBs, mercury, etc.?
Learn more about wild caught vs. farm raised salmon, including omega-3 content and contamination with PCBs, mercury, and other toxins.
Is it better for a fish oil (or krill oil) supplement to have more DHA than EPA?
Information on EPA and DHA in fish and krill oil supplements, including improving cognition, depression, anxiety, acne, and more.
How does the new prescription fish oil Epanova compare to Lovaza --and fish oil supplements?
Learn more about prescription fish oils like Epanova, Lovaza, and Vascepa and how they compare to each other and to supplements.
I heard that some types of fish oil are esterified and can dissolve plastic foam (polystyrene or Styrofoam). Is this right and, if so, should I be concerned?
Can some types of esterified fish oil dissolve plastic foam (polystyrene or Styrofoam), such as cups?
What supplements should I stop taking before surgery?
Info on which supplements to avoid before surgery due to increased risk of bleeding or interference with anesthesia.
Is it dangerous to use certain herbals, vitamins, or other dietary supplements when breastfeeding?
Find out which supplements should be avoided when breastfeeding, including medicinal herbs, soy, and flaxseed.