Bentonite clay
Bentonite clay in a face mask has some small human studies behind it for oily and acne-prone skin, but they tested formulated products, not a kitchen powder, so the evidence is limited. The popular claim that eating it detoxes the body has no sound human trial behind it, and in 2016 the FDA warned consumers off bentonite clay products with elevated lead that were sold for eating and skin use.
Do not give it to children, who are at risk from lead and, in one case report, from severe low potassium after oral and rectal use.
At a glance
Last reviewed 10 October 2026What it's used for
Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.
| Use | Evidence | What the research shows |
|---|---|---|
| Oily and acne-prone skin (mask)Compare remedies for skin → | Limited | In 75 adults with oily or combination skin, a formulated clay mask used twice weekly for 4 weeks was followed by lower sebum and fewer acne-related signs, but the abstract describes no comparison group and the authors are L'Oreal employees. A separate randomised add-on trial of 60 people with moderate acne found a bentonite mask with a plant extract cut total lesion count by about 55% and beat a placebo mask, so the effect cannot be put down to bentonite alone. A 2024 review calls for larger trials.1,2,3 |
| General skin care (oil absorption, hydration) | Limited | A 2024 dermatology review says evidence from laboratory, animal and preliminary clinical work suggests bentonites and montmorillonites absorb oil, and may calm inflammation and help wounds heal, but larger randomised trials are needed to confirm safety and benefit.3 |
| Eaten to detox or cleanse | Traditional | We found no controlled trial showing shop-bought bentonite detoxes the body. The one human safety trial we read used a processed calcium montmorillonite clay (NovaSil) designed to bind aflatoxin: 50 healthy adults took 1.5 or 3 g a day for 2 weeks, with mild gut symptoms such as abdominal pain and bloating, and no changes in blood electrolytes or minerals. That tested tolerance of a purpose-made product, not benefit, and does not extend to shop bentonite. The FDA found elevated lead in some bentonite clay products labelled for eating.4,6 |
| Hair and scalp (clay wash or mask)Compare remedies for hair & nails → | Traditional | We found no human study of bentonite on hair or scalp, so its use as a clay wash rests on popular practice. Clays are sold for oil absorption, but that is not evidence it improves hair or scalp health. |
How much
Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.
How people take it
Safety
Who should avoid
- Children and infants — lead risk (FDA) and a case of severe low potassium
- Eating it, especially if pregnant or breastfeeding — some products have elevated lead
- Constipation or bowel obstruction — a case report links large amounts to blockage
- Breathing in the dry powder — clay dust is an inhalation hazard in animal studies
- Near the eyes — bentonite injury is reported in rabbit eyes; keep masks away
Known interactions
Questions people ask
What are the benefits of bentonite clay?
The best-supported one is oily and acne-prone skin: small human studies of formulated clay masks found less sebum and fewer lesions, though the larger add-on trial used a plant extract too. Claims that eating it detoxes the body have no sound trial behind them.
Is bentonite clay good for hair?
We found no human study of it on hair or scalp. Clay washes are popular, but the evidence is 1 at best, and we can only say clay absorbs oil.
Is bentonite clay good for skin?
For oily or acne-prone skin, limited human evidence on formulated masks is positive. A 2024 review says larger randomised trials are needed, and a mask made from a kitchen powder has not been tested.
What are the side effects, and is it safe to eat?
We do not recommend eating it. The FDA warned in 2016 about bentonite clay products with elevated lead that were labelled for eating and skin use, and a 3-year-old developed severe low potassium after oral and rectal bentonite. Mild bloating, abdominal pain or constipation occurred with a purpose-made processed clay in a 2-week trial.
Make it yourself
DIY guides that use bentonite clay, with quantities, safety notes and an honest word on what they do.
Sources (7)
- Clinical study Zhang X, Zhang Z, Tao H, et al. Comprehensive assessment of the efficacy and safety of a clay mask in oily and acne skin. Skin Res Technol. 2023.
- Randomised trial Salimi S, Fakhri M, Saeedi M, et al. The Therapeutic Effects of a Bentonite-Based Facial Mask With Alcea sulphurea Extract on Acne Severity and Patient Experience: Add-On Randomized Controlled Clinical Trial. J Cosmet Dermatol. 2025.
- Review Zafar K, Lee A, Wang JY, et al. The potential cutaneous benefits of bentonites and montmorillonites. Arch Dermatol Res. 2024.
- Regulator US Food and Drug Administration. La FDA advierte a los consumidores sobre los riesgos que la arcilla de bentonita de Alikay Naturals, Bentonite Me Baby, conlleva para la salud. 2016.
- Case report Bennett A, Stryjewski G. Severe hypokalemia caused by oral and rectal administration of bentonite in a pediatric patient. Pediatr Emerg Care. 2006.
- Randomised trial Wang JS, Luo H, Billam M, et al. Short-term safety evaluation of processed calcium montmorillonite clay (NovaSil) in humans. Food Addit Contam. 2005.
- Safety assessment Elmore AR; Cosmetic Ingredient Review Expert Panel. Final report on the safety assessment of aluminum silicate, calcium silicate, ... attapulgite, bentonite, Fuller's earth, hectorite, kaolin ... montmorillonite, pyrophyllite, and zeolite. Int J Toxicol. 2003.
Last reviewed 10 October 2026 · Next review April 2027 · How we rate evidence
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.