Is Kirkland Fish Oil the Best Fish Oil?

bottle of Kirkland fish oils Super Concentrate Omega-3 1150 mg

Kirkland Fish Oil


Kirkland fish oil is a popular fish oil supplement made by Costco, a warehouse membership club found all over the world.

While you may find plenty of customer reviews on popular online retail sites, many of them focus on health claims from this particular fish oil.

This Kirkland fish oil review will focus on:

  • what type of fish are used to make the oil
  • what is the overall purity and quality of this fish oil
  • what are the omega 3 fatty acid concentrations
  • differences between Costco enteric and non-enteric coated fish oils
  • what are average customer reviews of this product
  • the average cost for kirkland fish oils



What are Kirkland Fish Oils Made From?


The Kirkland brand fish oils are made from primarily from sardines and anchovies found in deeper ocean waters.

The benefits of using these particular types of smaller fish species is they come with a lower risk of exposure to mercury, dioxins and other contaminants, compared to using larger-sized fish.


close-up of pile of sardines and anchovies used in kirkland fish oil

Sardines contain higher amounts of EPA and DHA

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

Mercury concentrations of sardines was 0.013 ppm and anchovies was about 0.016 ppm, compared to fresh tuna (0.689 ppm) and mackerel (0.73 ppm).

Costco’s choice to use smaller-sized fish may help reduce your exposure to mercury that could be found in larger fish. 


Kirkland Fish Oils Don’t Use “Farm-Raised” Fish

The advantage of using wild fish to make fish oils is they naturally have higher amounts of omega 3 fatty acids, compared to ‘farm-raised’ fish. This is due to living on a natural diet of consuming only other fish, algae or plankton found in the sea.

Wild fish live on a natural diet of other fish, algae or plankton; all which provides rich sources of the omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Farm-raised fish are 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 eating farmed fish.  Independent laboratory tests have shown that the average, farmed-raised salmon have 16 times the dioxin-like polychlorinated biphenyls (PCBs) at levels that raise health concerns.


Kirkland fish oil made through a process called molecular-distillation.

This method is commonly used to pharmacuetical-grade fish oils. It virtually 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 include: Fish Oil Concentrate, Gelatin, Glycerin, Water, Tocopherol.
– Each bottle provides 400 soft gels of 1000 mg providing 300 mg of EPA and DHA.
– Provides 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 at 9 cents/day.


2. Kirkland Signature Enteric-Coated One-a-Day Omega 3 Fish Oil Concentrate
– Also made from anchovies and sardines.
– Comes with an Enteric Coating which helps prevent fishy aftertaste by delaying absorption in the stomach.
– Ingredients include: Fish Oil Concentrate, Gelatin (non-bovine), Glycerin, Water, Vanillin, Tocopherol.
– Enteric Coating has 2 different formulations, depending on country:
  • 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 with each 1200 mg soft gel containing 410 mg. of EPA and 274 mg. of DHA.
– Provides a 57% omega 3 concentration per soft gel.
– Suggested Retail Cost is $14.99 per bottle.
– Recommended dosage is 1 soft gel per day at 8 cents/day.


Enteric-Coated Costco Fish Oil vs. Regular Costco Fish Oil

Choosing to use either enteric or non-enteric coated fish oils are a personal choice.

Kirkland fish oils are available in both forms:

  • enteric-coated product will last 180 days at 8 cents/day
  • non-enteric coating will last 133 days at 9 cents/day.

The Costco Enteric-Coated One-a-Day appears to be a better deal because:

  • will last 47 days longer than the non-enteric
  • costs less per soft gel
  • you get a higher concentration of EPA and DHA per soft gel (57% vs 30%).

a single kirkland fish oil soft gel with actual size shown on a tape measure

Size of Kirkland Fish Oil Soft Gel


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.

We found Kirkland fish oils to be fairly similar to Walmart’s private label brand Spring Valley Fish Oil, when we compared quality, price and omega 3 fatty acid concentrations.


Kirkland Fish Oils Gets Positive Reviews from Customers:


pouring open bottle of kirkland fish oil soft gels into open palm


At press time, the Costco website showed 68% of  customers gave these products 4.5 out of 5 stars reviews and 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 Amazon customers (75%) gave 5 out of 5 stars and 271 customers gave them 4 out of 5 stars (14%).

A total of 89% of all Amazon customer reviews gave Kirkland fish oils at least a 4 out of 5 rating. 



Kirkland fish oils appear to be a high quality product, at very affordable prices with many positive customer reviews.

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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Author Details
Author Details
Kevin is a full-time blogger with a passion for functional, whole food nutrition. A former Registered Respiratory Therapist with over 25 years experience in Intensive Care and Emergency Medicine, he also has additional training as a Certified Natural Products Advisor. He enjoys a vibrant lifestyle that includes healthy foods, workouts focusing on core strength with flexibility and longboarding to stay fit and agile.