Bentonite Clay

Overview and identity

Bentonite and montmorillonite are natural clay minerals formed from volcanic ash, long used in industry. [1] Searches are mostly for clay masks and "detox".

What the research shows

A 2024 review of the cutaneous (skin) benefits of bentonites and montmorillonites summarizes in vitro, animal and preliminary clinical evidence suggesting anti-inflammatory, wound-healing, oil-absorbing, drug-delivery, photoprotective and hydrating effects, and states that larger randomized clinical trials are needed to establish safety and efficacy. [1] That is not evidence that a clay mask treats a skin disease.

Detox claims

We found no sourced evidence that swallowing or applying bentonite removes toxins from healthy people, and NIH's NCCIH found no compelling research for detox diets. See Detox claims. [2]

Eating clay

Geophagy is the habit of consuming clay soil such as chalk or kaolin. A 2022 review says its safety is not fully established, that clay composition varies between sources, that some minerals found in geophagic materials are toxic to humans if ingested, and that there is a lack of adequate investigation into the toxicity of geophagy and more metabolic studies are needed. [3]

Safety

We could not find a regulator or review source we could read on swallowing bentonite clay (for example contaminant content), so we do not say it is safe to eat. Do not swallow clays or cosmetic products not intended as food, and do not put clay on serious, infected or worrying skin. Kaolin is a different clay with its own regulatory entry; see Kaolin clay.