Bentonite

Tolerability and safety

Irritation potential

Low

Allergen risk

Low

Pregnancy

Safe

Suitable for

Oily, Combination

Use with caution

Dry, Sensitive

About this ingredient

Bentonite is a natural clay of volcanic origin whose main mineral is montmorillonite. Formed by weathering of volcanic ash. Colour ranges from white to grey-green depending on iron and magnesium impurities. Mechanism. Montmorillonite microparticles have a layered crystal structure with a large specific surface area (50–70 m²/g) and a negative charge. This gives strong adsorption: bentonite pulls sebum, bacteria, and their byproducts from follicular openings. Mixed with water it swells 3–5-fold and forms a plastic paste that spreads evenly on skin. Where applied. Masks for oily and combination skin (Aztec Secret Indian Healing Clay, Sephora Clay Mask), cleansing toners, peelings, products for problem skin. Concentration 5–80% in masks. In Spain in Bioderma Sébium Mask, Avène Cleanance Mask, Uriage Hyseac Mascarilla. Evidence base. Few direct RCTs on bentonite masks in acne. Beringhs 2013 on ex vivo models showed significant sebum adsorption. In clinical practice, bentonite or kaolin masks are recommended as adjuncts in seborrheic and acne-prone skin once or twice a week. Safety. CIR confirmed safety in 2003 and 2018. With prolonged frequent use on oily skin it can cause dryness, tightness, and barrier disruption – limit frequency. Not indicated on dry or sensitive skin. Not for ingestion or as a food supplement: possible lead and silica impurities. Pregnancy and lactation – safe topically. No systemic absorption through intact skin. Particularly suitable for. Oily and combination skin, acne, cleansing routines once or twice a week. Not for patients with dry and sensitive skin, rosacea, or active atopic dermatitis.

Frequently asked questions