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Limited evidenceImmunity

Shark Liver Oil (Alkylglycerols)

Sold for its alkylglycerol content, with immune and anti-radiation claims dating back to mid-20th-century Scandinavian research. The modern human data concern blood lipids, not immunity.

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What the science says

  • Immune claims rest on old and preclinical work Limited evidence

    A review of alkylglycerols from shark liver oil summarised antitumour, antimicrobial and immunostimulant effects reported mostly in cell and animal experiments and in small historical clinical series. No modern randomized trial supports the immune or radiation-protection claims on labels.

  • A modern trial measured lipids, not infections Limited evidence

    A randomized supplementation trial found that shark liver oil raised endogenous plasmalogen levels and lowered some markers of dyslipidemia and inflammation. It had no infection or immune-function endpoint.

Dosage & safety

Studied doseNo dose validated for immune use. Labels typically provide 500–1000 mg of alkylglycerol-rich oil per day.
SafetySome shark liver oils are rich in vitamin A, and chronic excess vitamin A is toxic to the liver and teratogenic — check the label and avoid in pregnancy. Sharks are long-lived predators, so heavy metal and organic contaminant content depends heavily on sourcing and purification. Sustainability is a genuine concern with these products.

How to take it

TimingTiming does not matter.
With food?With a meal containing fat, since the alkylglycerols and any vitamin A are fat-soluble.
Worth knowingCheck the label for a vitamin A figure — some shark liver oils carry a great deal of it and others are purified to almost none.

Interactions

With medications

  • isotretinoin, acitretin and other retinoid drugs

    Shark liver oil can be rich in vitamin A, and the combined intake pushes you toward vitamin A toxicity. do not combine

With other supplements

  • cod liver oil, multivitamins and any retinol-containing product

    Preformed vitamin A is cumulative and chronically toxic to the liver, and teratogenic in pregnancy. add up total preformed vitamin A across every product you take

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does shark liver oil boost the immune system?

The evidence is limited: the immune and anti-radiation claims for shark liver oil rest on cell, animal and small historical studies. The one modern randomized trial measured blood lipids and plasmalogens, not infections or immune function.

Is shark liver oil safe?

Some shark liver oils are rich in vitamin A, which is toxic to the liver in chronic excess and teratogenic, so check the label and avoid shark liver oil in pregnancy. Heavy metal and contaminant levels depend heavily on sourcing and purification.

Can I take shark liver oil with cod liver oil or a multivitamin?

Only if you add up the total preformed vitamin A across every product, because shark liver oil can be rich in vitamin A and the intake is cumulative. Do not combine shark liver oil with isotretinoin, acitretin or other retinoid drugs.

How much shark liver oil per day?

No dose of shark liver oil has been validated for immune use. Labels typically provide 500–1000 mg of alkylglycerol-rich oil per day, best taken with a meal containing fat.

Scientific references

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