Shark Liver Oil and Alkylglycerols: The Ancient Immune Compound Nobody's Talking About

Quick summary: Shark liver oil contains a class of compounds called alkylglycerols (AKGs) that have been studied since the 1950s for their effects on immune function, bone marrow support, and radiation recovery. Despite a legitimate research history — much of it Scandinavian — AKGs remain almost entirely unknown in mainstream health and supplement circles. This article covers what they are, how they work, what a safe and effective dose looks like, and what to look for if you decide to supplement.

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If you ask most people about immune-supporting supplements, they'll probably name the usual suspects: Vitamin C, zinc, elderberry, and maybe Vitamin D. 

Those are all reasonable answers, and all very mainstream.

What you almost certainly won't hear is shark liver oil.

That's a problem. Not because shark liver oil is magic, but because the compound it contains, alkylglycerols, has a research tradition going back over 70 years. 

We’re talking about real, documented mechanisms, as well as a history of clinical use in oncology support and radiation recovery in Europe that most Americans have never encountered.

Now, as long-time MKS customers know, we're not interested in hype. What we're interested in is compounds that work, that have plausible mechanisms, and that have been studied in real clinical contexts — including human trials, not solely in animal models. 

Shark liver oil qualifies on all three counts – which is why we chose to develop Deep Defense, a shark-liver oil supplement made from sustainably harvested (non-threatened or endangered) shark. 

Let me walk you through what alkylglycerols actually are, what the research shows, and how to think about leveraging shark oil as part of your approach to healthy living.

What Is Shark Liver Oil?

Shark liver oil is extracted from the livers of certain shark species. 

The species matters (more on that in a moment), but the core point is that these sharks have disproportionately large livers relative to their body size. In some species, the livers account for up to 25% of the shark’s total body weight. 

Those livers are dense with specific lipids that serve biological functions: buoyancy regulation, oxygen metabolism, and immune support.

Before going further, one clarification worth making upfront: shark liver oil is not fish oil. They're completely different products with different active compounds and different applications. 

Fish oil is valued for its omega-3 fatty acids (EPA and DHA). Shark liver oil is valued primarily for its alkylglycerol content, a class of ether lipids with distinct mechanisms that have nothing to do with omega-3s. 

If you're already taking a quality fish oil and wondering whether shark liver oil is redundant, the answer is “no.” They don't overlap.

The primary active compounds in shark liver oil are alkylglycerols, or AKGs. These are ether lipids, which are structurally distinct from regular fatty acids (and from anything else commonly found in the supplement aisle). 

Here's something that puts them in context: human breast milk and colostrum are among the richest natural sources of AKGs, containing substantially higher concentrations than cow's milk. 

Bone marrow is another major reservoir.

In other words, these are not exotic foreign molecules your body has never encountered. They're compounds your biology already knows how to use. 

The fact that newborns receive a concentrated dose of them in their very first days of life tells you something important about their role in immune priming.

What Do Alkylglycerols Actually Do?

The research on AKGs isn't a single impressive study — it's a body of work spanning several decades, multiple countries, and both animal and clinical human data. 

However, a 2010 review published in Marine Drugs provides a thorough overview of the mechanisms and clinical applications.

Immune Modulation

AKGs appear to stimulate the production of white blood cells (specifically, granulocytes and macrophages). Macrophages are your innate immune system's first responders; they engulf pathogens, clear damaged cells, and signal to the rest of the immune system that something needs attention. 

The effect of AKGs appears to be modulatory rather than broadly inflammatory; priming the response rather than triggering indiscriminate activation.

In plain English, what that means is that AKGs help your immune system stay sharp and ready without pushing it into a state of chronic activation. 

Think of the difference between a well-trained security team on alert versus a panicked crowd responding to every noise. You want the former. Chronically overactivated immune responses are associated with systemic inflammation, which is the last thing most people need more of. AKGs appear to raise the ceiling of your immune capacity without unnecessarily pulling the trigger.

The same research identifies AKGs as precursors to ether phospholipids, which are structural components of immune cell membranes. 

In other words, AKGs don't just signal immune cells — they literally become part of their architecture.

Bone Marrow Support and Radiation Recovery

This is arguably the most well-documented area of AKG research, and it starts with a compelling clinical observation.

In 1952, Swedish physician Dr. Astrid Brohult was treating children with leukemia. Frustrated by limited results, she began giving the children fresh calf bone marrow. Her hypothesis was that bone marrow — the tissue responsible for producing blood cells — might contain growth-stimulating factors that could help the children's own marrow recover what it had lost to the disease. It wasn't a sophisticated biochemical theory; it was closer to first-principles reasoning – i.e., if a system is failing, give it the raw materials it’s built from.

So she began giving the children oral extracts isolated from fresh calf bone marrow. It wasn't glamorous science — there was no elegant mechanism theory, no double-blind protocol. Just a physician watching her patients deteriorate and deciding to try something rooted in first principles. 

In the early 1950s, she observed that those extracts appeared to stimulate the production of white blood cells — a maturing effect on the very cells the disease was destroying. That finding set her and her husband, Dr. Sven Brohult, on a years-long investigation to identify exactly which compound in the marrow was responsible.

They eventually isolated alkylglycerols as the responsible factor through a process of systematically separating out different fat classes from the bone marrow extract — treating it with alkali to break down ordinary fat, remained behind in what chemists call the "unsaponifiable fraction." 

That finding was first reported in Nature in 1960.

From there, subsequent Scandinavian researchers investigated AKGs specifically in the context of radiation therapy — and at this point, shark liver oil entered the picture as the practical delivery vehicle. AKGs had actually been identified in shark liver oil as far back as 1922, and the oil had long been used in Scandinavian folk medicine for its perceived effects on cancer and infections. 

Once the Brohults had confirmed AKGs as the active compound, shark liver oil was the logical next step: a commercially available, already-characterized source that could be produced at scale far more easily than calf bone marrow extracts. The findings in subsequent radiation studies were consistent: patients supplementing with shark liver oil experienced significantly less bone marrow suppression during radiation treatment than those who did not.

In one controlled study, cervical cancer patients given alkylglycerols prior to radiation therapy showed a 47% reduction in fistulas — a serious radiation injury — compared to controls. A separate clinical trial by the same research group found that administering alkylglycerols before radiation treatment produced measurable tumor regression and reduced mortality, with the effect being significantly more pronounced in patients under 60.

So the bottom line is: this isn't fringe research. 

It's documented clinical observation from a serious academic tradition, published in peer-reviewed journals and used in clinical practice in parts of Europe for decades.

Plasmalogen Precursors

A more recent angle on AKGs involves plasmalogens — a class of phospholipids found in high concentrations in the brain, heart, skeletal muscles, and immune cells. 

Plasmalogen levels decline with age and are reduced in metabolic disease. They function as structural membrane components and endogenous antioxidants.

AKGs can be metabolized into plasmalogens in the body, bypassing a rate-limiting step in the normal biosynthesis pathway. 

A 2021 randomized, placebo-controlled crossover study published in the Journal of Lipid Research found that shark liver oil supplementation significantly increased circulating plasmalogen levels while also reducing markers of dyslipidemia and inflammation in overweight men. 

This is a newer area of research, but the mechanism is sound and the implications are relevant to anyone thinking about long-term metabolic and cognitive health.

Tumor Environment and Angiogenesis

Some research suggests AKGs may inhibit platelet-activating factor (PAF), which plays a role in supporting tumor-associated blood vessel growth — a process called angiogenesis.

A mouse study published in Nutrition and Cancer found that oral AKG supplementation reduced tumor growth by a similar margin to whole shark liver oil, reduced metastasis dissemination by 64%, and curtailed markers of tumor vascularization — suggesting the antitumor activity of shark liver oil is primarily mediated by its AKG content.

I want to be clear here: I'm not saying shark liver oil treats or prevents cancer. That's not the claim. The research in this area is largely preclinical and based on animal models rather than human trials. 

The claim is that there are plausible mechanisms, supported by animal data and some clinical observation, suggesting that AKGs interact with pathways that matter in tumor biology. 

That's worth knowing, and it's why this compound has attracted ongoing interest in the oncology support context specifically.

Is Shark Liver Oil Safe?

At normal supplemental doses, shark liver oil is generally well-tolerated. 

The clinical research has largely used doses in the range of 100–600 mg of alkylglycerols per day, and no significant adverse effects have been reported at those levels.

One published case report documented acute toxic hepatitis in a 31-year-old woman who had been taking shark liver oil capsules twice daily for two weeks. 

Notably, the specific dosage and product formulation in that case were not detailed sufficiently to determine whether she was within, or significantly above, the standard supplemental range — an important variable given that product quality and AKG concentration vary widely across brands. 

Her symptoms resolved and liver enzymes normalized completely within eight weeks of discontinuation. 

It's a single case, not a pattern, but it reinforces the basic principle that dose and product quality matter with any bioactive compound.

The more practical concern with marine oils isn't the AKGs themselves, but oxidation and contamination. Rancid oil is counterproductive regardless of what it contains, and marine oils sourced carelessly can carry heavy metals and persistent organic pollutants. 

That's an argument for buying from companies that test and publish their results, not an argument against shark liver oil as a category. 

It's also why the purity data we publish for every batch of Deep Defense matters.

Not All Shark Liver Oil Is the Same

Species selection and purity testing are the two things that separate a legitimate product from a generic one.

Species: Different shark species produce different lipid profiles. Some products are formulated primarily around squalene — which has its own benefits as an antioxidant and immune adjuvant — but are lower in alkylglycerols. If AKGs are what you're specifically after, you need a product that discloses and standardizes AKG content. "Shark liver oil" on a label with no further detail tells you almost nothing useful.

The species used in Deep Defense is Squalus blainville, which is the longnose spurdog — a cold-water, depth-adapted shark found in the Eastern Atlantic and Mediterranean, typically caught at depths of 300 to 500 meters. 

Importantly, these sharks are not caught for their livers. The entire animal is used for human food consumption. The livers — once discarded — are what we responsibly source to create this product. 

We firmly oppose shark finning and work only with partners committed to sustainable fishing practices. 

We chose this species specifically for its AKG concentration, and every batch is standardized to 200 mg of alkylglycerols per serving.

Purity: Marine oils carry real contamination risks — mercury, lead, cadmium, arsenic, PCBs, and dioxins to name a few. 

We test every batch of Deep Defense and publish the Certificate of Analysis so you can verify what you're getting rather than taking our word for it. 

For the current batch as of this writing (SLO-022, manufactured January 2025): mercury, lead, and cadmium all came in below 0.01 mg/kg — well under the regulatory limit of 0.1 mg/kg. 

Inorganic arsenic is below 0.098 mg/kg. 

PCBs and dioxins both conform to EU standards. 

The peroxide value of 2.4 meq O2/kg, and TOTOX value of 13.1, both indicate the oil is fresh and not oxidized.

That last point matters more than most people realize. 

Oxidized oil isn't just ineffective — it generates lipid peroxidation products that can contribute to the very oxidative stress you're trying to address. 

A low peroxide value is a sign of quality sourcing and proper handling. If a company won't publish its COA, treat that as a signal.

How Much Shark Oil Should You Take?

The clinical research on AKGs has generally used doses in the range of 100–600 mg per day of alkylglycerols specifically — not just total shark liver oil. 

This distinction matters because the concentration of AKGs in shark liver oil varies significantly by species and processing method. A product listing only total oil weight without specifying AKG content gives you no way to know what you're actually getting.

Deep Defense delivers 1,000 mg of shark liver oil per serving across two capsules, standardized to 200 mg of alkylglycerols — a dose that falls within the studied clinical range. 

For those wanting more aggressive support — during a treatment protocol, for example — the research supports going higher within that range.

There's also a reasonable case for cycling rather than taking it year-round. Using it through winter, during periods of high physical or immune stress, or as targeted support around a medical protocol makes more practical sense than treating it as a permanent daily staple for most people.

Who Might Actually Benefit?

I'll be straightforward: shark liver oil isn't something I think everyone needs to take every day. It fits specific contexts well, and being honest about that is more useful than overselling it.

People undergoing chemotherapy or radiation are the most evidence-backed use case. The Scandinavian research on bone marrow protection during radiation treatment is real, the mechanism is plausible, and this is the context where AKGs have been most consistently studied in humans. 

If someone I cared about were going through treatment, Deep Defense would be one of the first things I'd look into — in consultation with their medical team, of course.

Anyone with chronically suppressed immunity — frequent illness, slow recovery, consistently high stress load — might also benefit from the immune-modulatory effects. 

This includes people whose immune function is being chronically taxed by training volume, sleep debt, environmental toxin exposure, or sustained high-output work. 

Post-cancer recovery falls into a similar category for those thinking about long-term immune resilience.

High-frequency travelers and people in high-exposure environments are worth mentioning too. Frequent air travel, shift work, and persistent environmental toxin loads all place ongoing demands on immune function — largely because they suppress white blood cell activity and macrophage responsiveness, the very pathways AKGs have been shown to support. 

Most people underestimate the cumulative immune cost of these stressors.

Why We Made Deep Defense

Kathy and I formulated Deep Defense because we couldn't find a similar product we were confident in. 

Most shark liver oil products on the market either don't specify AKG content, don't disclose their source species, or don't publish contamination testing. 

We wanted something that met the same standard as everything else in our product lineup: clean sourcing, verified purity, standardized active compound content, and complete transparency on testing.

Each serving is two capsules delivering 1,000 mg of shark liver oil standardized to 200 mg of alkylglycerols. 

The capsule shell is bovine gelatin — consistent with our broader approach to ancestral sourcing. 

Shelf life is three years stored properly and out of direct sunlight. 

The full COA for every batch is publicly available.

The Bottom Line

Alkylglycerols are one of those compounds that make you wonder how they stayed under the radar for so long. Your bone marrow makes them. Breast milk concentrates them for newborns. A Swedish physician was documenting their effects in leukemia patients in the 1950s. 

The mechanisms — immune modulation, bone marrow support, plasmalogen precursor activity — are real and documented across decades of peer-reviewed research.

The fact that they're barely mentioned in mainstream health conversations says more about how supplement trends work than it does about the science. 

People buy whatever is being marketed loudest. 

The interesting compounds are almost always hiding in the research, not on the front shelf at the pharmacy.

If you take immune health seriously — not as a trend, but as a long-term investment in your resilience — alkylglycerols are worth understanding. 

And if you want a product that's been sourced, tested, and standardized to a level we'd be comfortable giving to our own family, that's exactly what we built Deep Defense to be.