Wax Esters, EPA and DHA: How Are They Different? | Arctic Ruby Oil

The Quick Answer: Wax Esters vs EPA vs DHA

This means asking whether something contains “wax esters or EPA” is a little like asking whether a package contains “a box or an apple.”

One describes the structure carrying something; the other describes what that something is.

What Is an Omega-3 Fatty Acid?

Omega-3 fatty acids are members of a family of polyunsaturated fatty acids.

Fatty acids are essentially chains of carbon atoms with a carboxylic acid group at one end.

The term omega-3 refers to the location of the first carbon-carbon double bond when counting from the methyl—or omega—end of the fatty-acid chain.

In an omega-3 fatty acid, that first double bond begins at the third carbon from the omega end.

Many omega-3 fatty acids exist in nature, but three of the most commonly discussed are:

• ALA — alpha-linolenic acid
• EPA — eicosapentaenoic acid
• DHA — docosahexaenoic acid

Another omega-3 relevant to Calanus oil is SDA — stearidonic acid.

According to the National Institutes of Health Office of Dietary Supplements, EPA and DHA are commonly obtained from fish, seafood and marine oils, while ALA occurs primarily in certain plant oils.¹

What Is EPA?

EPA stands for eicosapentaenoic acid.

Chemically, EPA is designated:

This notation tells us that EPA contains:

• 20 carbon atoms
• 5 carbon-carbon double bonds
• an omega-3 configuration

EPA is classified as a long-chain polyunsaturated omega-3 fatty acid.

After absorption, EPA can become incorporated into various lipid pools and cell membranes and can serve as a precursor for multiple biologically active signaling molecules.^{1, 2}

Marine organisms can contain EPA in several different molecular forms. It may be associated with triglycerides, phospholipids, wax esters or other lipid structures depending upon the organism.

The EPA molecule is still EPA. What differs is the molecular structure to which it is attached before digestion.

What Is DHA?

DHA stands for docosahexaenoic acid.

Chemically, DHA is designated:

DHA therefore contains:

• 22 carbon atoms
• 6 carbon-carbon double bonds
• an omega-3 configuration

DHA is also a long-chain polyunsaturated omega-3 fatty acid.

DHA is an important structural component of cell membranes and is particularly concentrated in tissues such as the brain and retina. ¹

As with EPA, DHA can occur naturally within different lipid structures depending upon its source.

How Are EPA and DHA Different?

EPA and DHA are both long-chain omega-3 fatty acids, but they are different molecules.

DHA is two carbon atoms longer than EPA and contains one additional double bond.

Because their molecular structures differ, EPA and DHA do not necessarily behave identically after they enter the body.

Research has shown differences in how they are incorporated into lipid pools and utilized in different tissues.²

For this reason, EPA and DHA should not be thought of as interchangeable names for the same substance.

What Is a Wax Ester?

A wax ester is fundamentally different from EPA or DHA.

It is not a particular fatty acid.

Instead, a wax ester is a lipid molecule created when a fatty acid is chemically attached to a long-chain fatty alcohol.

Chemists describe this connection as an ester bond.

Many combinations are possible because numerous different fatty acids and fatty alcohols can participate in the molecule.

Therefore, “wax ester” describes a class of molecules rather than one individual substance.

Wax esters occur widely in nature. They can serve functions including energy storage, protection and buoyancy.

In the North Atlantic copepod Calanus finmarchicus, wax esters primarily serve as a remarkable long-term energy-storage system.

How Can EPA or DHA Be Part of a Wax Ester?

This is where the terminology becomes much easier to understand.

Remember that every wax ester contains:

If the fatty-acid portion of that molecule happens to be EPA, the wax ester contains EPA.

If the fatty-acid portion is DHA, that wax ester contains DHA.

If the fatty-acid portion is SDA, then it contains SDA.

Many other fatty acids can also occupy that position.

This is why an oil can simultaneously be described as wax ester-rich and as containing EPA and DHA.

The descriptions refer to different levels of its chemistry.

Are All Wax Esters Omega-3 Wax Esters?

No.

This is another important distinction.

The fatty acid attached to a wax ester does not have to be an omega-3 fatty acid.

Wax esters can contain:

• saturated fatty acids
• monounsaturated fatty acids
• omega-3 polyunsaturated fatty acids
• other polyunsaturated fatty acids

Calanus oil contains a complex mixture of wax esters incorporating numerous fatty acids.

EPA and DHA are important components of that system, but they represent only part of the total fatty-acid profile.

This is why the phrase “wax ester-based omega-3 oil” is useful: the oil contains omega-3 fatty acids within a lipid system dominated by wax esters.

Why Are Wax Esters Important in Calanus finmarchicus?

Calanus finmarchicus is a tiny copepod living throughout the North Atlantic.

Its environment is intensely seasonal.

During productive periods, particularly when phytoplankton are abundant, Calanus feeds and accumulates large lipid reserves.

These reserves help the animal survive extended periods when it descends into deeper water, greatly reduces its activity and relies on previously stored energy.

Much of this energy is stored as wax esters.

Scientific analyses have found that wax esters can account for roughly 85% or more of the lipid content in commercial Calanus oil and similarly high percentages of stored lipid in the animal itself depending on life stage and season. ³

In other words, wax esters are not an ingredient artificially created during processing.

They are part of the natural biology of Calanus finmarchicus.

What Fatty Acids Are Found in Calanus Oil?

Calanus oil contains a broader mixture of fatty acids than the EPA and DHA numbers commonly emphasized on omega-3 supplement labels.

Published analyses of commercial Calanus oil have reported notable amounts of:

• SDA — stearidonic acid (18:4 n-3)
• EPA — eicosapentaenoic acid (20:5 n-3)
• DHA — docosahexaenoic acid (22:6 n-3)
• ALA — alpha-linolenic acid
• cetoleic acid
• gondoic acid
• oleic acid
• numerous additional fatty acids

A 2020 scientific review reported approximate fatty-acid concentrations in the commercial Calanus oil examined of:

These values describe the oil investigated in the scientific literature and should not be interpreted as guaranteed specifications for every harvest or finished consumer product.

Natural marine oils can vary with season, location, life stage, processing and formulation.

The Other Half of a Wax Ester: Fatty Alcohols

If EPA, DHA and other fatty acids represent one side of the wax ester, what is on the other side?

A long-chain fatty alcohol.

Published analyses of Calanus oil have identified eicosenol and docosenol among its predominant long-chain fatty alcohols. ³

Zooca®, the supplier of the Calanus oil used in Arctic Ruby Oil, refers collectively to this long-chain alcohol fraction as marine policosanols.

These compounds are not merely mixed into the oil afterward.

They are intrinsic components of the wax ester molecules created by Calanus finmarchicus.

This is one reason looking only at EPA and DHA milligrams does not fully describe the chemical composition of Calanus oil.

What Happens to a Wax Ester During Digestion?

Before the components of a wax ester can be absorbed, the ester bond joining the fatty acid and fatty alcohol must be broken—or hydrolyzed.

In simplified form:

Research on dietary waxes has demonstrated that mammalian digestive systems possess enzymes capable of hydrolyzing wax esters and releasing their fatty-acid and fatty-alcohol components. ⁴

Research using Calanus oil has similarly demonstrated digestion of its marine wax esters.⁵

Wax esters are highly hydrophobic and structurally different from triglycerides and phospholipids. As a result, their digestion does not necessarily follow the same time course as those other lipid forms.

Researchers have proposed that Calanus wax esters may undergo slower digestion and hydrolysis than conventional dietary triglycerides.

The biological significance of this different digestive behavior remains an active area of research.

It should not automatically be interpreted to mean that slower digestion is either superior or inferior.

Can Humans Absorb EPA and DHA From Wax Esters?

Yes.

This question was examined directly in a randomized human clinical trial published in Lipids in 2016. ⁶

Eighteen healthy adults participated in a randomized crossover study.

One treatment provided 4 grams of Calanus oil containing approximately:

• 260 mg EPA
• 156 mg DHA

with the fatty acids supplied predominantly within the wax ester-rich oil.

Researchers measured EPA and DHA in plasma over the following 72 hours.

Both EPA and DHA increased after consumption, demonstrating that the fatty acids had been absorbed.

The study was important because wax esters had historically sometimes been assumed to be poorly utilized by humans.

Human clinical evidence demonstrated that this assumption could not simply be applied to dietary Calanus oil.

What Happens With Longer-Term Supplementation?

Acute absorption tells researchers what happens over several hours. For dietary supplements, however, another important question is what happens after repeated use over weeks or months.

A randomized 12-week study published in 2023 directly compared Calanus oil with fish oil and krill oil. ⁷

Sixty-two participants completed the trial.

The groups received approximately:

• Calanus oil: 242 mg EPA + DHA per day
• Fish oil: 248 mg EPA + DHA per day
• Krill oil: 286 mg EPA + DHA per day

Researchers measured the participants' Omega-3 Index, which reflects EPA and DHA in red blood cell membranes.

After 12 weeks, the average increases were:

The differences among groups were not statistically significant.

The researchers concluded that Calanus oil increased long-term omega-3 status to a degree comparable with the fish oil and krill oil used in the study.

This result is noteworthy because the three oils carry their fatty acids through substantially different lipid structures.

Does the Lipid Structure Change EPA or DHA?

No. EPA remains EPA, and DHA remains DHA.

What changes is the molecular structure carrying the fatty acid before digestion.

For example, EPA can be incorporated into:

• a triglyceride
• a phospholipid
• an ethyl ester
• a wax ester

The EPA molecule itself is still eicosapentaenoic acid.

However, the surrounding lipid structure can influence how the larger molecule is emulsified, hydrolyzed and absorbed.

A comprehensive 2025 review of EPA and DHA bioavailability concluded that chemical form can influence short-term absorption. ⁸

Importantly, the authors also noted that differences seen in acute absorption studies often do not translate into meaningful differences in long-term omega-3 status.

That is particularly relevant to dietary supplements, which are normally consumed repeatedly rather than as a single dose.

Wax Esters vs Triglycerides vs Phospholipids

Understanding these molecular structures helps explain the difference among major marine oils.

This is why saying that Calanus oil, fish oil and krill oil are all simply “omega-3 oil” misses an important part of their chemistry.

All can provide EPA and DHA.

But they do not necessarily deliver those fatty acids within the same natural lipid structure.

Where Does SDA Fit Into the Picture?

EPA and DHA receive most of the attention in discussions about marine omega-3 oils, but Calanus oil also contains a significant amount of SDA, or stearidonic acid.

SDA contains 18 carbon atoms and four double bonds.

It lies in the metabolic pathway between shorter-chain omega-3 fatty acids and EPA.

Humans can convert SDA toward EPA more readily than they convert ALA toward EPA because SDA bypasses an earlier rate-limiting metabolic step.⁹

Conversion from SDA all the way to DHA, however, remains limited.

Published analysis of Calanus oil has reported SDA at approximately 7% of total fatty acids in the oil examined, making it one of the more prominent omega-3 fatty acids in its natural lipid spectrum. ³

This is another reason Calanus oil should not be characterized solely by its EPA and DHA content.

Understanding EPA and DHA Numbers on Supplement Labels

Consumers often compare omega-3 products simply by looking at the number of milligrams of EPA and DHA.

Those numbers are useful, but they do not tell you everything about the oil.

Consider two different measurements:

A highly concentrated fish-oil supplement may contain a very large percentage of EPA and DHA.

Calanus oil is different because EPA and DHA represent only part of a broader wax ester-rich lipid system.

Its natural composition also includes:

• SDA
• other omega-3 fatty acids
• long-chain monounsaturated fatty acids
• long-chain fatty alcohols
• naturally occurring astaxanthin

Therefore, comparing Calanus oil with a concentrated fish oil solely by asking which one has more EPA and DHA per gram does not compare their complete compositions.

On the other hand, if a consumer's sole objective is obtaining a specific large quantity of EPA or DHA, the EPA and DHA amounts on the label remain important information.

What Does This Mean for Arctic Ruby Oil?

Arctic Ruby Oil uses Zooca® Calanus® Oil derived from the North Atlantic copepod Calanus finmarchicus.

That means its marine lipid structure differs from conventional fish oil and krill oil.

The defining feature is not simply that Arctic Ruby Oil contains EPA and DHA.

Many marine oils contain EPA and DHA.

What makes Calanus oil unusual is the natural molecular environment in which those and other fatty acids occur:

a predominantly wax ester-based marine lipid system.

Human clinical research has demonstrated that the EPA and DHA contained in wax ester-rich Calanus oil are bioavailable. ⁶

Longer-term research has also shown that Calanus oil can increase the Omega-3 Index to a degree comparable with the fish oil and krill oil formulations studied when similar amounts of EPA and DHA were consumed.⁷

Common Misconceptions About Wax Esters, EPA and DHA

Misconception #1: Wax ester is another type of omega-3 fatty acid.

It is not. A wax ester is a lipid structure composed of a fatty acid joined to a long-chain fatty alcohol.

Misconception #2: EPA, DHA and wax esters are competing ingredients.

They are not. EPA or DHA can actually form the fatty-acid component of a wax ester.

Misconception #3: Every wax ester contains EPA or DHA.

No. Wax esters can contain many different fatty acids. EPA and DHA are only part of the natural fatty-acid spectrum of Calanus oil.

Misconception #4: EPA and DHA become different fatty acids when carried in a wax ester.

No. The molecular carrier changes, but EPA remains EPA and DHA remains DHA. During digestion, the ester bond is hydrolyzed and the components become available for absorption and metabolism.

Misconception #5: Slower digestion means poor absorption.

Not necessarily. Human clinical studies demonstrate that EPA and DHA from wax ester-rich Calanus oil are bioavailable.

Misconception #6: More EPA and DHA automatically means a better marine oil.

EPA and DHA concentration is an important characteristic, but it is not the only way marine oils differ. Lipid structure, fatty-acid spectrum and other naturally occurring components can also differ substantially.

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