My Detailed Review of Kirkland Fish Oil

kirkland fish oil review

Kirkland Fish Oil

Is Kirkland Fish Oil a good fish oil supplement to use?

This omega 3 supplement is made by Costco, a very popular warehouse membership club found all over the world.

The advantages of being a Costco member is you can buy many popular retail items at a discount, and this also includes nutritional supplements.

When it comes to buying the best fish oil supplement, there are many factors to consider;  how many omega 3 fatty acids you get per dose, what are the actual ingredients and more.

Here you’ll learn more about Costco’s fish oil, what it’s made from, and differences between their enteric and non-enteric coated soft gels. 


What are Costco Fish Oils Made From?

One of the things I like about Kirkland fish oils is that they’re made from sardines and anchovies caught in deep ocean waters.

Researchers claim that it’s better to use smaller fish to make fish oils because there’s a lower risk of exposure to mercury, dioxins and other contaminants that you could get from eating larger fish.

Comparison of Mercury Levels in Commercial Fish published by the FDA show sardines and anchovies contain over 50 times less mercury than larger -sized fish, such as fresh tuna and mackerel.

The FDA studies showed sardines and anchovies contained about 0.013 and 0.016 ppm (mercury concentration mean) compared to fresh tuna and mackerel at 0.689 ppm and 0.73 ppm.


Kirkland Fish Oils Avoid Using “Farm-Raised” Fish:

Costco claims they don’t use farmed-raised fish to make their oil.

The advantage of using wild fish to make fish oils is they contain higher levels of omega 3 fatty acids. This is due to living on a natural diet of consuming only other fish, algae or plankton found in the sea.

The disadvantage of using farm-raised fish is they’re usually fed pellets (and even antibiotics) which may lower the quality of these healthy and essential fatty acids.

The Environmental Working Group (EWG) has also expressed concerns about consumers eating farmed fish.  Their independent laboratory tests found, on average, farmed salmon have 16 times the dioxin-like polychlorinated biphenyls (PCBs) at levels that raise health concerns.


Kirkland fish oil is also made through a process called molecular-distillation. This is actually a very effective method commonly used to make pharmacuetical grade fish oils. It removes almost all traces of mercury, PCB’s and other contaminants. Costco claims their mercury levels are undetectable at less than 0.1 parts per billion.



Kirkland Fish Oil Comes in Two Forms:


1. Kirkland Natural Signature Omega 3 Fish Oil

  • It’s made from anchovies and sardines.
  • Ingredients on the label include: Fish Oil Concentrate, Gelatin, Glycerin, Water, Tocopherol.
  • Each bottle provides 400 soft gels of 1000 mg providing 300 mg of EPA and DHA.
  • This will give you a 30% omega 3 fatty acid concentration per soft gel.
  • Suggested Retail Cost is $9.99 per bottle.
  • Recommended dosage is 3 soft gels per day or 9 cents/day.

2. Kirkland Signature Enteric-Coated One-a-Day Omega 3 Fish Oil Concentrate

  • This one is also made from anchovies and sardines.
  • It comes with an Enteric Coating which helps prevent that fishy aftertaste by delaying absorption in your stomach.
  • Ingredients on the label include: Fish Oil Concentrate, Gelatin (non-bovine), Glycerin, Water, Vanillin, Tocopherol.
  • I found that the enteric coating has 2 different formulations:
    • The USA Costco website says it may contain Hydroxypropyl Methylcellulose Phthalate, Stearic Acid, Methacrylic Acid Copolymer, Oleic Acid, Ethylcellulose, Sodium Alginate, , Medium Chain Triglyceride, Triacetin, Ammonium Hydroxide, Polyethylene Glycol
    • The Canadian Costo version contains bovine gelatin, glycerine, purified water, pectin, sorbital, natural tocopherols
  • Each bottle provides 180 soft gels. Each 1200 mg soft gel contains 684 mg of omega 3 fatty acids (410 mg of EPA and 274 mg of DHA).
  • This will give you a 57% omega 3 concentration per soft gel.
  • Suggested Retail Cost is $14.99 per bottle.
  • Recommended dosage is 1 softgel per day or 8 cents/day.

costco fish oil

Size of Kirkland Fish Oil Soft Gel

If you compare the Regular Kirkland Natural fish oil to the Enteric-Coated One-a-Day brand, the enteric-coated product will last 180 days at 8 cents/day and the non-enteric coating will last 133 days at 9 cents/day.

I believe that the Costco Enteric-Coated One-a-Day is the better deal because it’ll  last 47 days longer than the non-enteric, it costs lower per soft gel and you only have to take one soft gel per day. You also get a higher concentration of omega 3 fatty acids per soft gel (57% vs 30%).

Both types of Costco fish oil come in a 1000 mg soft gel and they’re about 1 inch long and 3/8th inches wide.

Another advantage of taking enteric-coated fish oil soft gels is they help delay disintegration in the stomach until the soft gel reaches the small intestine.

This is supposed to improve your body’s digestion and absorption of the fish oil’s active ingredients.



Consumer’s Reports Analyzes Costco Enteric-Coated Fish Oil

Consumers Report analyzed a number of fish oil supplements and found two samples of the Kirkland Signature Fish Oil failed a USP disintegration test for the enteric coating, in spite of label claims these fish oils are “USP Verified”.

Could this have been simply a bad batch? It’s possible, but the Consumer’s Report article went on to state that Kirkland Signature Enteric-Coated Fish Oils did not meet the label claim.

Whether you choose to let this finding change your mind about buying the Enteric-Coated One-a-Day is up to you.

You can get Kirkland Fish Oils without the enteric-coating and it’s actually received many positive reviews from customers.



Kirkland Fish Oils Gets Positive Reviews from Customers:

kirkland costco fish oilSo what do actual consumers think of this brand of fish oil?

At press time, the Costco website showed 36 customers (68%) out of 53 gave these products 4.5 out of 5 stars and 8 customers gave them 4 out of 5 stars.

So 83% of the total customer reviews at gave at least a 4 out of 5 rating.

Kirkland Fish Oils Reviews at also seem pretty favorable. As of May 2018, 1416 out of 1889 total customers (75%) gave 5 out of 5 stars and 271 customers gave them 4 out of 5 stars (14%). So a total of 89% of all customer reviews gave at least a 4 out of 5 rating. Again, I think that’s pretty impressive for a wholesale brand product.

Based on customer reviews, many claimed to like the high quality and lower cost.

When you compare the EPA and DHA dosages in Kirkland Fish Oil to other brands, such as Walmart’s private label brand Spring Valley Fish Oil, you’ll find that they’re fairly similar. 


Summary Review of Costco Fish Oils:

Costco appears to have succeeded in providing a high quality product at very affordable prices. If you’re a health-conscious consumer on a budget, this may be product that’ll meet your needs.

You can pick up this product at your local Costco store or search on-line for Kirkland Signature Omega-3 Fish Oil Concentrate.



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