How to Choose the Best Fish Oil

white plastic bottle on side with best fish oil soft gels spilling out

Fish oils can come packaged as soft gel capsules and bottled oils. They’re also sold under different names, such as pharmaceutical-grade, ultra-concentrated, molecularly-distilled, enteric-coated and triple-strength and many more.

So which is the best one to buy?  I’ve been using these products for a number of years and I’ve tried and tested quite a few different types.

In this article, you’ll learn about different types of products, comparing soft gels vs bottled liquids, the purpose of enteric-coated soft gels,  product reviews and more.

Fish is an excellent source of the omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Omega 3 fatty acids are found in the fatty tissue of fish that eat phytoplankton (algae) or consume other fish that have accumulated EPA and DHA in their bodies.

There’s conflicting research on the health benefits of omega 3 fatty acids. However, several studies show they can help reduce inflammation and lower elevated triglyceride levels.

These types of products have become one of the most popular nutritional supplements.  Recent industry numbers estimate the world fish oil market at just under $2 billion, and its predicted to climb to over $3 billion by the mid-2020’s.

Unfortunately, the industry isn’t completed regulated and not all products are created equal. If you compare two different brands side-by-side, you may find a difference in the actual ingredients, purity, dosage amounts and freshness.

We believe that the best fish oil will have excellent overall purity and quality of the ingredients.

It should also be certified by a third-party laboratory that analyzed the oil for the omega 3 concentrations. The oils should also have the minimally acceptable level of detectable contaminants allowed by regulatory bodies.

What’s the Difference Between Norwegian, Pharmaceutical-Grade and Prescription-based Products?

In spite of all the different marketing terms used to sell these products, you’ll find there’s generally three (3) broad categories that all fish oil products fall under.

These three categories are Norwegian, pharmaceutical-grade and prescription-based oils.

Summary of Terms:

  1. Norwegian-based products – are made from fish caught in the Norwegian Sea.
  2. Pharmaceutical-grade products – term used to describe products made by following same standards used to make pharmaceutical medications either through manufacturing, quality control or purification.
  3. Prescription-based products – products made in an FDA-approved lab that also require a Doctor’s prescription.

The following information will take a closer look at each category.

1. What are Norwegian Fish Oils?

Norwegian oils are primarily made from fish caught in the Norwegian Sea, such as haddock, Atlantic salmon, herring and Atlantic halibut.

bottle of nordic naturals omega-3 purified fish oils

Nordic Naturals is a Norwegian-Based Oil

According to The Norwegian Seafood Council, Norway has some of the largest cod stocks in the world. Cod liver oil was one of the first fish oils to be used by ancient Norwegians.

Norwegian oils can be made by different methods.  In the 1980’s, the fish were boiled until the oil rose to the top of the vat (a process called ‘rendering’). Unfortunately, this process was not able to remove all the toxins in the flesh of the fish, such as PCB’s and mercury. Some of these unwanted contaminants remained in the oil.

New innovations in chemical engineering, such as molecular distillation, remove most of the saturated fats and PCB’s by distillation.

Molecular-distilled oils are highly-purified. They usually provide high omega 3 fatty acid concentrations with minimally detectable levels of mercury and other contaminants.

Are Norwegian fish oils better than products?

This depends on who you’re asking….

Some marketers claim that the fish used to make these products contain naturally higher levels of omega 3 fatty acids and less exposure to mercury and contaminants.  They claim this is due to the cleaner, colder waters of the Norwegian Sea.

Other manufacturers disagree and claim the process used to make the oil is more important than where the fish came from.

I believe that the overall quality and purity of the oil is more important than what type of fish were used to make the oil.

Some examples of products made from fish caught in the Norwegian Sea are Nordic Naturals and Carlson Labs. I’ve tried both products and found them to be high quality oils.

2. What are Pharmaceutical-Grade Oils?

Pharmaceutical-grade fish oils is a term used by many companies to describe their product.

In our article on pharmaceutical grade fish oils, we highlight how there’s no standardized or regulated method for making a ‘pharmaceutical-grade’ oil. It’s not an FDA-regulated term, so any manufacturer can use it to describe their product in order to sell it to you.

So it’s up to you, the consumer, to determine how credible and reliable the marketer’s claims are about a specific product.

pharmaceutical grade fish oil capsules in blister pack

Pharmacuetical-grade soft gel capsules

One of the biggest concerns for anyone using these products is exposure to mercury and side effects.

Choosing a product claiming to be ‘pharmaceutical-grade’ may help alleviate some of these concerns, however, this doesn’t mean that it will provide a pharmaceutical-grade purity or minimize side effects.

If you do choose a ‘pharmaceutical-grade’ product, you should look for the following:

  • High concentrations of eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA).
  • Undetectable levels of mercury, PCB’s, dioxins and other contaminants.
  • Made in FDA-approved labs following Good Manufacturing Practises (GMP).

Not only should your product meet the above criteria, you should also look for products that have been certified and analyzed by a 3rd party laboratory.

Why you Want a Certificate of Analysis (COA) :

Some companies or manufacturers may hire a 3rd party laboratory to analyze their products and provide a Certificate of Analysis.

These certificates will tell you that the product has been analyzed for the amount of omega 3 fatty acids and has been tested for any detectable levels of mercury, dioxins and other contaminants.

What’s a Certificate of Analysis look like?

Here’s a sample certificate from PurityProducts Ultra Pure Omega 3.  This particular certificate tells us the actual measured amounts of EPA and DHA, the amount of detectable contaminants (including mercury, arsenic, PCB’s) and more.  You also get told the date of manufacture and the specific batch and lot numbers of the product analyzed.

There are also a number of different companies or labs that will provide this service.

Types of 3rd Party Certification Organizations:

What are IFOS Fish Oils? – IFOS (International Fish Oil Standards) is an independent lab that analyzes and certifies products for other companies. In this article we discuss how these products are rated according to criteria set by many international organizations and showcase some sample products that are IFOS-certified.

GOED (Global Organization for EPA and DHA) –  this organization follows guidelines set out in the GOED Voluntary Monograph. They check for omega 3 fatty acids levels and environmental contaminants, such as mercury, PCB’s, dioxins and furans.

IVO (International Verified Omega-3) – this lab claims to test for over 400 potential contaminants, checks for compliance with regulatory fishing and harvesting methods, and uses an internationally-approved processing and manufacturing method to ensure the safety, purity and potency.

Many of the above organizations may also follow national or international standards set forth by different regulatory bodies.

Some examples of these regulatory bodies are:

  • Council for Responsible Nutrition – this is a trade organization representing dietary supplement manufacturers and suppliers. It’s voluntary to join and its members are expected to follow federal and state regulations governing dietary supplements for safety, manufacturing and quality control
  • United States Pharmacopeia (USP) –  the USP helps supplement manufacturers stay competitive by providing the USP Verified Mark for their products. Some of the best fish oils will have the USP Verified Mark on the label. This ensures consumers that the item contains what’s stated on the label, doesn’t contain harmful contaminants and was made according to FDA current Good Manufacturing Practices (GMP).
  • Europena Pharmacopeia Standards (EPS) – this one is mostly found in European countries. It operates under the European Directorate for the Quality of Medicines (EDQM), the European Pharmacopeia Monograph which sets standards for the quality control of medicines and some nutritional supplements.
  • IVO (International Verified Omega-3) – This is an independent, not-for-profit organization that offers certification of oils that meet a comprehensive set of quality checks, including testing for almost 400 possible contaminants. Our article on Costco’s Kirkland Fish Oil Review revealed that they are certified by IVO.

Just remember that consistent and regular testing is the only way to ensure you’re getting a highly-purified product that contains what’s stated on the ingredient label.

3. What’s a Prescription Fish Oil?

These are considered the best fish oils above all others and you’ll need a prescription from you doctor to get them.

They’ve all undergone extensive testing and research and have proved to the FDA that it does what it’s prescribed for.

These products also contain exactly what’s stated on the ingredient label and the manufacturer will disclose any possible side effects from the product.

All prescription oils are manufactured in FDA-approved facilities and they must follow strict guidelines during the entire manufacturing process.

They may contain high concentrations of certain isolated omega 3 fatty acids. In most cases, the concentrations are much higher when compared to some store-bought oils.

Examples of prescription fish oils are Lovaza and Vascepa.

prescription fish oil

Lovaza Soft Gels

The main benefits of using a prescription-based product is you get exactly what’s stated on the ingredient label.

One of the biggest questions consumers have is what’s the best fish oil dosage?  Using a prescription oil will guarantee you get a specific omega 3 fatty acid dosage based on your doctor’s recommendation.

Are prescription fish oils better than regular oils?

These are superior to many off-the-shelf products because of the research and FDA-approval process required for these types of products

However, the higher cost and need for a prescription may be a barrier to some consumer’s budgets.

Summary of Prescription, Pharmaceutical-Grade and Norwegian Fish Oils

While the above information looks at the different types of products, choosing the best fish oils will ultimately depend on your personal choice.

Here’s a summary of the different types of products and their advantages and disadvantages.

Prescription Fish Oils:


-provides exact dosages of EPA and DHA

– meet all FDA-approved guidelines for pharmaceutical medications


– requires a doctor’s prescription

– may cost significantly more than store-bought fish oils

Pharmaceutical-grade Fish Oils:


– may use a 3rd party laboratory to analyze and certify their fish oil


– you may get different concentrations of EPA and DHA, compared to a prescription-based products

– there’s no guarantee that what you see on the ingredient label is what you’ll get in every single bottle.

Norwegian Fish Oils:

– Norwegian fish oils are products made from fish sourced from the Norwegian sea which may or may not provide assurances of quality or purity.

Soft Gels vs Bottled Oils – Which is Better?

bottle of liquid fish oils and soft gels

Fish oils come in bottled oils and soft gels

In our article, “A Closer Look at Liquid Fish Oil vs Capsules”, we looked at the advantages and disadvantages to each type.

To summarize, fish oils are sold in bottled liquids and soft gel capsules. It will come down to your personal preference to choosing which form you’ll want.

Fish oil soft gels are very common.  The oils are encapsulated in soft gels which are usually made from gelatin.  The gelatin can be made from animal or plant-based materials.  Animal-based gelatin is usually sourced from the skin, hooves, connective tissue and bones of cows or pigs.

Some of the advantages of soft gel capsules is they’re generally tamper-proof which helps avoid contamination. Encapsulation helps keep the ingredients stable and they also provide a uniform dosage. However, some people may have difficulty swallowing pills or they may be reluctant to products made from animal sources.

Some consumers may also have health issues that affect their ability to properly digest fish oil soft gels or capsules. Enteric-coated fish oils are capsules or soft gels that have a special coating which may help improve digestion and absorption.

enteric coated soft gels

Enteric coated and Non-coated soft gels

In our article, the Pros and Cons of Enteric-Coated Fish Oil we looked at how they may help increase absorption and digestion of the oil.

However, some products may only be sold in lower dosages or they could use synthetic or artificial ingredients for the enteric coating.

Liquid fish oils are bottled oils that are available in many different flavors. The most common bottled oils are lemon-flavored, such as lemon-flavored cod liver oils.  These flavorings can be made from natural or artificial ingredients. Many of the fish oils for children are sold with these special flavorings to help make them more agreeable to a child’s palate.

One of the advantages of using a bottled oil is they usually provide a higher dosage of omega 3 fatty acids per spoonful, compared to a single soft gel or capsule.  This is because a teaspoon of liquid fish oil is about 5 grams, where as a single fish oil soft gel is usually only 1000 mg (1 gram) in size.

Choosing between a fish oil soft gel and bottled liquid may come down to what specific fish oil dosage your want and if you experience any side effects from fish oils.

Product Reviews

Based on the above criteria, here are product reviews of some popular brands:

Consumer’s Guide to Nature Made Products – this is a popular supplement sold by Pharmavite, a nutritional supplement company based in Northridge, California. They have a number of different products based on overall omega 3 concentrations and enteric-coated fish oils.

Is Spring Valley Fish Oil the Best Fish Oil? – this is Walmart’s private label brand that includes a wide range of different ingredients and omega 3 dosages. We take a closer look at the overall purity and quality of this popular big-box retailer brand.

Kosher Fish Oils – What You Need to Know – With a wide range of flavorings and ingredients used to make oils, you may need to find a kosher fish oil.  This article takes a closer look at kosher products and how to choose the best kind.


When it comes to buying the best fish oils, there are a number of important factors to consider. If you want a highly-purified product that will provide what’s indicated on the ingredient label then you should look for some sort of certification or 3rd party analysis.

Aside from using prescription fish oils, you should look for the following criteria:

  1. Provides the amount of EPA and DHA you require
  2. Is available in either bottled liquids or soft gel capsules
  3. Verification of purity and quality, either through a Certificate of Analysis or other 3rd Party Laboratory Testing
  4. Is there any additional ingredients or additives added to the fish oil?

Choosing high quality nutritional supplements that are proven to be safe, effective and affordable can help you achieve the benefits you seek.


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