Which omega-3 is best? Fish oil, krill oil, algae oil, cod liver oil and Calanus oil compared

Omega-3 supplements come in many forms, from fish oil and krill oil to cod liver oil and plant-based alternatives such as algae oil. Although they all contain omega-3 fatty acids, they differ considerably in composition, dosage, form and use.

In this guide, we compare the main sources of omega-3 to help you decide which one is best suited to your needs.

What types of omega-3 supplements are there?

The five most common types of omega-3 supplements are:

• fish oil
• krill oil
• cod liver oil
• algae oil
• Calanus oil

All of these sources provide omega-3 fatty acids, but they differ in their fatty acid profile, source, level of processing, stability and additional nutrients.

Some products are designed to provide high doses of EPA and DHA, while others offer a broader spectrum of fatty acids and bioactive compounds.

What should you look for when choosing an omega-3 supplement?

Most omega-3 supplements focus on two fatty acids: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Each source provides these fatty acids in a different form and nutritional context.

Some oils provide highly concentrated doses of EPA and DHA, while others contain a broader spectrum of fatty acids and bioactive compounds.

Omega-3 supplements also differ in several important ways:

• Form (triglycerides, phospholipids, wax esters)
• Stability (susceptibility to oxidation)
• Source (fish, krill, plankton, algae)
• Level of processing and exposure to heat

Together, these factors influence how an oil behaves in the body. Want to learn more about factors such as fatty acid form, oxidation, processing, lab testing and purity? Read our guide on how to recognise a high-quality omega-3 supplement.

What are the main differences between omega-3 sources?

Fish oil as a source of omega-3

Fish oil is often considered the standard source of omega-3. It provides high doses of EPA and DHA.

How fish oil is processed

Fish oil is essentially a concentrated omega-3 extract and is the result of a lengthy industrial process. Most fish oil starts out in triglyceride form, but during production it is often converted into ethyl esters and sometimes converted back into triglycerides. These processes allow for higher concentrations, but can affect absorption, stability and oxidation.

Oxidation and quality of fish oil

Fish oil is relatively susceptible to oxidation, partly due to heat exposure during production and prolonged storage. Its quality therefore depends heavily on freshness, the addition of antioxidants and its source. Fish oil from smaller fish, such as sardines and anchovies, generally contains fewer contaminants. Oxidation values, including the TOTOX score, provide insight into the oxidation status of the product.

Sustainability of fish oil

A fish oil supplement can be a sustainable choice, but this depends heavily on where the fish comes from and how it is caught. Manufacturers often use smaller fish species such as sardines and anchovies. Certifications such as MSC (Marine Stewardship Council) and Friend of the Sea can help identify more sustainable options. Ultimately, the environmental impact depends on fishing practices, origin and the scale of production.

When should you choose fish oil?

Fish oil can be a good option if you are looking for a high dose of EPA and DHA. Its quality depends heavily on freshness, source and production methods.

Krill oil as a source of omega-3

Krill oil comes from small crustaceans. What sets it apart is that its omega-3 fatty acids are largely present in phospholipid form.

How krill oil is processed

In terms of processing, krill oil sits somewhere between fish oil and minimally processed oils such as Calanus oil or cod liver oil. Krill is processed immediately after harvesting to prevent spoilage. The oil is extracted using mechanical techniques or solvents.

Krill oil remains closer to its natural form than many fish oils. Intensive concentration and conversion into ethyl esters are not required. However, it is not entirely unprocessed. Extraction and refining take place under controlled conditions, helping to preserve phospholipids and astaxanthin.

When should you choose krill oil?

Krill oil may be a good option if you value phospholipids and naturally occurring astaxanthin.

Cod liver oil as a source of omega-3

Cod liver oil is a traditional source of omega-3, extracted from the liver of cod.

It contains not only omega-3 fatty acids but also vitamins A and D. This makes it more of a whole-food-derived product than an isolated omega-3 supplement.

How cod liver oil is processed

The fatty acids in cod liver oil naturally occur in triglyceride form, the same form in which fats are found in food. Chemical processing is not required.

Extra virgin cod liver oil is considered the least processed form of cod liver oil. It is a minimally processed product, comparable in this respect to Calanus oil.

Vitamins A and D in cod liver oil

In addition to omega-3, cod liver oil naturally contains vitamins A and D. This sets it apart from most other omega-3 supplements.

Oxidation and quality of cod liver oil

Antioxidants such as rosemary extract or tocopherols are often added to help limit oxidation. The TOTOX score can provide insight into the oxidation status of the oil.

Sustainability of cod liver oil

The sustainability of cod liver oil depends heavily on its source. It is often produced as a by-product of fish already caught for human consumption.

When should you choose cod liver oil?

Cod liver oil may be a good option if you want to obtain vitamins A and D from a traditional food source alongside omega-3.

Algae oil as a source of omega-3

Algae oil is the only plant-based source of EPA and DHA. It is produced from microalgae in a controlled environment, making it free from ocean-borne contaminants and a logical choice for vegetarians and vegans.

Fatty acid profile of algae oil

Algae oil provides EPA and DHA without the broader range of fatty acids found in some other omega-3 sources. This gives it a more targeted fatty acid profile.

Most algae oil products contain relatively more DHA and less EPA.

How algae oil is processed

Algae oil is produced through the controlled fermentation of microalgae. The fatty acids naturally occur in triglyceride form. After extraction, however, the oil is often processed further to achieve higher concentrations of EPA and DHA. This can involve chemical concentration and re-esterification.

Differences in algae oil quality

Not all algae oils are the same. The microalgae (Schizochytrium sp.) used in NoordCode High EPA & DHA are naturally rich in EPA. As a result, intensive processing is not required.

Oxidation and stability of algae oil

Like fish oil and cod liver oil, algae oil is susceptible to oxidation. The addition of antioxidants therefore plays an important role in maintaining its stability.

When should you choose algae oil?

Algae oil is a good option if you are looking for a vegan omega-3 supplement or want a clean and sustainable source of EPA and DHA. Because it is produced in a controlled environment rather than sourced from the ocean, algae oil is free from ocean-borne contaminants and does not put pressure on marine ecosystems.

Calanus oil as a source of omega-3

Calanus oil is extracted from Calanus finmarchicus, a species of zooplankton found in the North Sea, Norwegian Sea and northern Atlantic Ocean. It sits low in the food chain and feeds mainly on phytoplankton.

How Calanus oil is processed

The zooplankton is frozen directly on the boat to preserve freshness. During processing, nothing is added and nothing is removed. No chemicals are used. Aside from energy and fresh water, the only additional input is a minimal amount of enzymes.

Sustainability and purity of Calanus oil

Calanus finmarchicus sits low in the marine food chain and feeds mainly on phytoplankton. Its short life cycle of around one year means it accumulates relatively few environmental contaminants. The population also renews itself annually, contributing to the sustainability of this source. This makes Calanus oil a clean and sustainable source of omega-3.

What makes Calanus oil unique: wax esters

What makes Calanus oil unique is that its fatty acids are stored as wax esters. In a wax ester, a fatty acid is bound to a fatty alcohol (policosanol). This makes the oil less susceptible to oxidation than triglycerides and phospholipids. It also allows for a more gradual release and absorption.

Additional bioactive compounds in Calanus oil

In addition to EPA and DHA, Calanus oil also contains:

• SDA (stearidonic acid)
• Policosanols
• Astaxanthin

At approximately 1.8 mg of astaxanthin per serving, this is considerably higher than the amount found in many krill oil products.

When should you choose Calanus oil?

Calanus oil may be a good option if you prefer:

• a broad fatty acid profile
• minimal processing
• additional bioactive compounds, such as astaxanthin
• a stable source of omega-3

NoordCode Ultimate Omega Formula is an example of a Calanus oil supplement.

Which omega-3 is best for your goal?

Looking for an omega-3 that is closest to food?

Calanus oil and cod liver oil are the most obvious options. Both provide other fatty acids and additional nutrients alongside EPA and DHA. They are well suited to a food-first approach where minimal processing is important.

Want to increase your omega-3 intake more specifically?

Fish oil, krill oil or algae oil may be better suited. These omega-3 sources are primarily used to provide EPA and DHA in higher concentrations, making them suitable if you want to target your daily omega-3 intake more specifically.

Looking for a plant-based alternative to fish oil?

Choose algae oil. Algae oil is the only plant-based source of EPA and DHA and is produced from microalgae in a controlled environment.

Looking for a stable omega-3 with additional nutrients?

Calanus oil is an interesting option. Alongside EPA and DHA, it contains SDA, policosanols and astaxanthin, while its wax ester form makes the oil naturally stable.

Which omega-3 is best?

The best omega-3 depends mainly on your goals and preferences. If you want a high intake of EPA and DHA, fish oil and algae oil are logical choices. If you prefer a broader fatty acid profile and minimal processing, Calanus oil or cod liver oil may be a better fit.

Omega-3 supplements differ fundamentally in their composition and use. Some focus on providing high doses, while others offer a broader, more naturally occurring fatty acid profile. The best choice depends on what you are looking for: a daily nutritional foundation or more targeted supplementation. Understanding the differences makes it easier to choose the option that best suits your needs.