Beta-Sitosterol

Evidence by route

About this ingredient

Beta-Sitosterol is a natural plant phytosterol structurally close to cholesterol. Found in sunflower, rapeseed, avocado, nuts, and soybean oil. In pharmaceuticals it is an oral agent for lowering cholesterol and for benign prostatic hyperplasia; in cosmetics it is an emollient and anti-inflammatory ingredient. Mechanism. On skin it embeds into intercellular stratum corneum lipids, taking the functional niche of cholesterol, which – with ceramides and fatty acids – forms the three-component lipid matrix of the barrier. Maintaining the 1:1:1 lipid ratio (cholesterol:ceramides:fatty acids) reinforces the barrier in dry and atopic skin. Suppresses inflammatory signalling via NF-κB inhibition in vitro. Where applied. Creams and emollients for dry and atopic skin, post-retinoid and post-procedure products, hand and body balms, products for mature skin. Concentration 0.1–2%. In Spain part of Avène Cold Cream, La Roche-Posay Lipikar, Bioderma Atoderm. Evidence base. Direct topical RCTs on beta-sitosterol monotherapy are few. Most data come from phytosterol complexes or plant oils (soy, avocado) where it is one of the actives. Orally – Cochrane review Wilt 2002 showed symptom improvement in BPH, not relevant to cosmetics. Safety. CIR confirmed safety of phytosterols in cosmetics in 2013. Hypoallergenic, non-comedogenic, non-irritating. Allergy is rare, described as isolated cases with cross-reactivity to latex and soy. Pregnancy and lactation – safe topically. Used without restriction. Oral use (supplements) in pregnancy lacks adequate data – usually avoided. Particularly suitable for. Dry and atopic skin, scaling, impaired barrier (after retinoids, peels, laser), age-related dryness. Works well in ceramide formulas with cholesterol-to-ceramide-to-fatty-acid ratio 1:1:1, where sitosterol substitutes for cholesterol.

Tolerability and safety

Skin types

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