Supplement analysis backed by scientific evidence · PT

← All supplements
Limited evidenceJoints & skin

Squalene

Squalene is a natural lipid your own skin makes and a well-validated vaccine adjuvant, but as an oral supplement it has almost no controlled human evidence. Topically it is a decent, evidence-light emollient; orally the claims run far ahead of the data.

What the science says

  • Improves skin hydration and barrier function Limited evidence

    Squalene and its stable hydrogenated form squalane are major components of human sebum and function as occlusive emollients, which is why they are ubiquitous in cosmetics. Reviews of squalene in cosmetic dermatology describe emollient and antioxidant activity and good tolerability, but rigorous randomized trials measuring transepidermal water loss or clinical dryness against a standard moisturizer are scarce. Applied topically it performs about as well as other lightweight occlusives; taken by mouth, there is no good evidence it improves skin.

  • Lowers cholesterol or protects the heart Limited evidence

    This one is arguably backwards. Squalene is the direct biosynthetic precursor of cholesterol, and human studies show that dietary squalene raises serum squalene and can modestly increase cholesterol synthesis markers. Animal work is inconsistent, and no human RCT shows squalene supplementation lowers LDL or cardiovascular risk.

  • Boosts immunity or fights cancer Limited evidence

    Squalene emulsions such as MF59 are genuinely effective vaccine adjuvants — but that is an injected emulsion in a formulated vaccine, not a swallowed capsule, and the adjuvant effect does not transfer to oral use. Anticancer claims rest on cell and rodent studies of squalene's antioxidant and detoxification-enzyme effects, with no clinical trials in people.

Dosage & safety

Studied doseThere is no established supplemental dose. Shark-liver-oil capsules typically supply 500–1,000 mg squalene once or twice daily, a range set by manufacturers rather than trials. Dietary intake in Mediterranean populations from olive oil runs roughly 200–400 mg/day and comes with polyphenols and monounsaturated fat that do have cardiovascular evidence — a better vehicle if you want squalene in your diet. Topical squalane is used undiluted as a facial oil.
SafetyOral squalene is well tolerated in the short term; the common complaints are oily burps, loose stools and mild GI upset. The bigger issues are sourcing and specific risks: most cheap squalene comes from shark liver, which raises both sustainability concerns and contaminant questions (shark liver oil can carry heavy metals and persistent pollutants), while olive-derived and yeast-fermented squalene avoid both. Aspiration of oily supplements can cause lipoid pneumonia, a real risk in people with swallowing difficulty. Squalene adjuvants were once alleged to cause Gulf War illness or autoimmunity; large safety reviews of MF59-adjuvanted vaccines have not supported that, and in any case it is irrelevant to oral use. Choose plant-derived squalane for skin, and get dietary squalene from olive oil.

Scientific references

Where to buy

View on iHerb

Referral link — this site may earn a commission on purchases.

Related in Joints & skin