Ask Alina: How Do I Select A Good Fish Oil Supplement?

Q: I am using Nature’s Bounty Norwegian Cod Liver Oil, but I’m not sure if that’s good. How can we tell if a fish oil is good or bad? Please tell me what I should look for when buying fish oil. 

Saba N. 

A: When I was working at a health food store, there’s a simple 3P criteria that I made up to help customers make this decision:

1) Potency
2) Purity
3) Purpose


Every good fish oil brand will label the individual amounts of EPA and DHA (in milligrams) on the bottle. EPA and DHA are the two main types of Omega 3 that are found in fish oil, and have distinctive benefits. EPA is better for heart health, mood and reducing inflammation, whereas DHA is excellent for brain health i.e. improving memory, focus and concentration.

Ideally, both EPA and DHA should at the least add up to 500mg, with 1000-1500mg being ideal. Word of warning: some brands lump everything together under “Fish oil” or “Omega 3” on the label, so you have no idea how much individual EPA or DHA you’re getting.

I like the formulation of the Nutrasea brand which contains 750mg of EPA and 500mg of DHA. 


The source of your fish oil is extremely important. Larger fish tend to accumulate more mercury due to their longer lifespan, whereas smaller fish tend to eat plants, accumulate less mercury and have shorter lifespans as well. A good brand will label the types of fish used, such as sardines, anchovies and mackerel. Note: steer clear of brands using tuna, which are very high in mercury!

You’ll also want to look for: 

  • A third-party testing stamp on the bottle to ensure no trace of heavy metals or toxins
  • No added preservatives or artificial flavours
  • Non GMO verification

You have to ask yourself what you’re using it for. If it’s to improve your memory, find a fish oil with a higher DHA to EPA ratio like this one from Nordic Naturals.

If it’s for mood or heart health, get a higher EPA to DHA ratio like this Mood Support fish oil from Genuine Health. 

For overall health, a regular fish oil formula like this Nutrasea one works well.

Lastly, cod liver oil is similar to fish oil, except that it also contains relatively high amounts of Vitamin D and Vitamin A as well. If you’re living in colder climates where you need more Vitamin D, or have a requirement for more Vitamin A (like acne), this could be a great option.

About Alina

I'm a Holistic Nutritionist based in Toronto, Canada and my official title is Certified Nutritional Practitioner (CNP). I received my diploma in Applied Holistic Nutrition from the Institute of Holistic Nutrition. I'm a coach and an educator. Follow Alina on Facebook, Twitter, Pinterest and Instagram for all of the latest updates.
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