Bentonite

other

What is it

Bentonite is a clay formed from weathered volcanic ash, composed primarily of montmorillonite, a layered aluminosilicate mineral. It is used in industrial applications, cosmetics, and as a supplement for its swelling, adsorption, and ion-exchange properties.

How it works

Bentonite clay has a unique layered structure with a large negative surface charge. When hydrated, the layers swell and the clay forms a viscous gel. Its negative charges attract positively charged molecules and ions, allowing the clay to bind certain mycotoxins, heavy metals, and bacterial toxins in the digestive tract through ion exchange and adsorption. The most studied application of bentonite is in animal feed, where it has been shown to bind aflatoxins and reduce their toxicity. Some research has examined this 'binder' function in humans, with limited but generally positive evidence for binding certain mycotoxins. For everyday supplement claims (detoxification, weight loss, beauty), bentonite's evidence is weak. The clay binds many substances non-selectively, including nutrients and medications, which is its main limitation for routine use. Heavy metal contamination of the clay itself is a real safety concern.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Mycotoxin binding

Grade C

Moderate evidence

Bentonite has been shown to bind aflatoxins and some other mycotoxins in animal studies and limited human research. May reduce exposure to dietary mycotoxins, particularly in populations with contaminated food supplies.

Diarrhea (some types)

Grade C

Moderate evidence

Bentonite-related clays have been used historically and in some clinical settings for non-infectious diarrhea, with modest evidence of benefit.

Topical skin conditions

Grade C

Moderate evidence

Bentonite face masks and topical applications have traditional use for oily skin, acne, and minor skin irritation. Limited but reasonable evidence for soothing and absorbing oil and toxins from skin surface.

Detoxification (oral)

Grade F

Limited evidence

Marketing claims about general 'detoxification' lack scientific support and may be outweighed by risks of heavy metal contamination. Liver and kidneys handle most detoxification functions.

Weight loss

Grade F

Limited evidence

Claims for weight loss through 'cleansing' are not supported by evidence. Any short-term weight changes are due to bowel content shifts, not fat loss.

4 commercial forms

Bentonite clay powder

Loose powder for mixing with water; topical or internal use.

Standard form. Quality varies widely. Choose only products with verified low heavy metal content. Calcium bentonite and sodium bentonite have slightly different properties.

Liquid bentonite

Pre-mixed; convenient but more expensive per gram.

Pre-hydrated bentonite for oral use. Easier than mixing powder but provides smaller doses per serving.

Bentonite capsules

Dose-controlled; convenient.

Encapsulated dry powder for oral use. Capsules dissolve in the stomach, then clay hydrates and acts in the gut.

Bentonite face mask or body wrap

Topical use for cosmetic purposes.

Powder mixed with water and applied to skin. Used for oily skin and as a cosmetic treatment.

Dosage

There is no RDA. As a supplement, bentonite is sometimes used at 1 to 3 teaspoons (5 to 15 g) mixed with water daily, though clinical evidence supporting any specific dose is limited. For occasional use, smaller amounts may be safer. External use as a face mask or body wrap follows manufacturer instructions.

When and how to take it

If used orally, take bentonite at least 2 to 4 hours apart from medications, supplements, and meals to avoid absorption interference. Mix with plenty of water and follow with additional water to prevent constipation. Daily long-term use is not recommended. External use can be performed at any time.

Safety

Major safety concerns include heavy metal contamination (lead, arsenic) of bentonite products. Several FDA warnings and recalls have been issued for bentonite supplements containing dangerous lead levels. Aspiration is a risk if powder is inhaled. Constipation, bowel obstruction, and electrolyte disturbances can occur with high or prolonged intake. Long-term oral use is not well studied for safety.

Who should be cautious

People should choose only third-party tested bentonite products with verified low heavy metal content. Those with kidney disease, electrolyte disorders, or chronic constipation should avoid oral bentonite. Pregnant women should not use oral bentonite due to limited safety data and contamination risks. Children should not be given oral bentonite. People on essential medications should take it separately and avoid daily use.

Interactions

Bentonite binds many substances in the gut, including medications, vitamins, and minerals. Take bentonite at least 2 to 4 hours apart from any medication or supplement. The clay can affect potassium and other electrolyte balance with prolonged use. May interact with antacids and other gastrointestinal medications.

Frequently asked questions

Is bentonite safe to swallow?⌄

Quality matters enormously. Several bentonite supplements have been recalled for dangerous lead contamination. If using orally, choose only products with verified third-party heavy metal testing. Limit duration and frequency of use.

Will bentonite interfere with my medications?⌄

Yes. Bentonite binds many oral medications and reduces absorption. Take at least 2 to 4 hours apart from any medication. Avoid daily use if you take essential prescriptions.

Does bentonite remove heavy metals from the body?⌄

Bentonite may bind some heavy metals in the gut, reducing absorption of newly ingested metals. However, removing metals already stored in tissues requires medical chelation therapy; bentonite cannot do this.

Can I use bentonite for face masks?⌄

External use of cosmetic-grade bentonite is generally safe and has traditional use for oily skin and minor blemishes. Follow product directions; do not let dry masks crack and irritate skin.

What's the difference between sodium and calcium bentonite?⌄

Sodium bentonite swells more in water (used in cat litter and industrial sealing). Calcium bentonite (sometimes called calcium montmorillonite) is more often used for human supplements and cosmetics. Both share basic adsorption properties.

References

  • Bentonite (Wikidata) — Wikidata link
  • Bentonite (ChEBI) — ChEBI link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.