Bentonite clay is formed from aged volcanic ashes and has an extraordinary capacity to absorb water and electrolytes. It is used to detox, cleanse skin and hair, and support digestion. It might also fight infections, help you lose weight, and relieve allergies. Learn more about this healing clay and why it might be a good idea to start using it more often.
What Is Bentonite Clay?
Bentonite clay tops the list of healing clays, many of which have been used for enhancing health since ancient times .
Bentonite clay forms when volcanic ashes react with sea water and take up its minerals. This clay has no taste or smell and its color can vary from light (cream, yellow, green) to darker (brown, black) tones depending on its impurities. Its consistency is very soft and it doesn’t stain [2+, 3+].
Bentonite clay is named after its largest source in the world (Fort Benton, Wyoming). The name of its main component, montmorillonite, derives from the place where it was first discovered (Montmorillon, France). The US is the largest producer, followed by China, Greece, and India .
You may be surprised to know that humans have been using clays both internally and externally throughout history. Scientists think that “geophagy” or earth-eating was an adaptive behavior for acquiring nutrients from soil and eliminating gut parasites and toxins [1, 5, 6].
- Nutrient deficiencies
- Diarrhea and other digestive issues
- Skin irritation
- Hair cleansing and softening
What makes bentonite clay different from similar clays, such as kaolin clay? Let’s take a look.
Kaolin Clay vs Bentonite Clay
Both clays are common ingredients of face masks but have different effects. Since bentonite is a better absorbent, it can remove more fat and toxins from the skin. In turn, kaolin is more efficient at exfoliating dead skin due to its larger particles .
People with oily skin would do better with bentonite masks, while those with drier, more sensitive skin should choose kaolin.
Aside from these two clays, Fuller’s earth is another option for skin care. It’s great for absorbing toxins and reducing the detrimental effects of pollution on the skin .
- Binds to toxins and enhances detox
- Promotes skin health
- Supports digestion
- May help fight obesity, infections, and allergies
- Relatively safe
- Some benefits are insufficiently researched
- May cause nutrient deficits at high doses
- May bind to and inactivate drugs
- Low quality of some products (toxic levels of lead)
Components & How It Works
The main component is montmorillonite, a soft clay formed by layers of silica and alumina. Montmorillonite is normally bound to many clay minerals, especially sodium, calcium, magnesium, and aluminum [8+, 3+].
Bentonite may also contain small amounts of impurities such as other clays (illite, kaolinite) and crystalline silica (quartz, cristobalite). While the levels typically found in this clay are not dangerous, both kaolin and crystalline silica dust may cause lung diseases if breathed in large amounts. Silica dust is also linked to autoimmune disorders, kidney damage, and cancer [8+, 3+].
Montmorillonite’s negative charge gives rise to bentonite clay’s effects. Similar to a magnet, it attracts positively charged molecules and binds them to its surface (adsorbs them). This way, it can trap many heavy metals and toxins, preventing them from entering the body [12, 9].
Montmorillonite particles have an astonishingly large surface area, which gives them a high capacity to bind toxins. The particles also take up water alongside toxins, infusing both into the spaces between their layers and causing the whole clay to swell .
Health Benefits of Bentonite Clay
1) Enhances Detox & Binds Toxins
By binding to different substances in the gut – from fungal toxins to pesticides to heavy metals – bentonite clay prevents their uptake into the bloodstream and promotes their elimination.
Here’s an overview of all the toxins it can help you detox.
Aflatoxins are toxins produced by the mold that infects several food crops such as maize and peanuts. Being very toxic to animals, it’s not surprising that they also have numerous harmful effects on people. Aflatoxins have even been linked to liver cancer [13+].
Bentonite clay binds to aflatoxins and prevents poisoning. In 3 clinical trials on almost 300 people exposed to aflatoxin, bentonite clay (1.5 – 3 g/day) reduced aflatoxin levels in the blood and urine [14+, 15, 16].
Fumonisin is another dangerous toxin produced by the same mold. In a clinical trial on almost 200 people exposed to this toxin, bentonite clay (1.5 – 3 g/day) reduced its levels in urine .
Bentonite clay also reduced the levels and toxic effects of an array of fungal toxins (aflatoxin, fumonisin, deoxynivalenol, and ochratoxins) in farmed animals. It improved weight gain, nutrient uptake, milk production, and fertility while reducing liver, kidney, and gut damage [18, 19, 20, 21, 22, 23, 24].
In calves poisoned with a toxic plant (Lantana camara), bentonite clay reduced liver damage and death rates. However, this clay failed to reduce the toxicity of another plant, locoweed, in sheep and rats. Poisoning with this plant is not common in humans, though [25, 26, 27].
To sum it up, if you’re battling mold illness/CIRS, adding bentonite clay to your regimen may help.
Paraquat is an extremely toxic but widely used weed killer (herbicide). Even a small amount of the concentrated solution is deadly and has been used in suicide attempts. Two analyses found paraquat traces (up to 25 mg/g) in approximately 10% of marijuana samples. Since a small percentage can pass into smoke, marijuana smokers may be exposed to this chemical [28+, 29+, 30, 31].
Organophosphates are another type of toxic pesticides that are absorbed by the skin and build up in the body. Bentonite clay reduced organophosphate absorption by human skin tissues .
Lead is a metal that is toxic to several enzymes and organs (especially the brain). People can be exposed to lead through contact with lead products, dust, and water, and eating contaminated meat. Bentonite clay reduced lead buildup in farmed pigs and lambs, which not only increased their weight gain but also made their meat safer to eat [44, 45, 46].
Cadmium may contaminate soils and groundwater near industrial areas. It’s associated with cancer, sterility, and organ damage in humans. In fish taking cadmium with the feed, bentonite clay reduced its toxic effects [47, 48].
To sum up, bentonite clay binds to and traps heavy metals. If you think you might be exposed to toxic levels, taking in bentonite clay can prevent them from passing into your blood.
Excess Fluoride in Drinking Water
Moderate fluoride levels are considered beneficial for bone and teeth health. In turn, exposure to high levels (fluorosis) may cause stains teeth stains, weaken bones, and damage the brain, glands, and liver. Fluoride levels under 1 – 1.5 mg/L in drinking water are regarded as safe [49+, 50].
Bentonite clay can remove excess fluoride from drinking water. The clay needs to be activated to increase its positive charge and allow fluoride uptake – a process that authorities can use to clean public water supply. It might be possible to achieve the same at home, but this would be challenging since activated bentonite is not widely available [51+, 52+, 53, 54].
2) Soothes the Skin
Adding bentonite clay to your skincare routine is a good way to soothe conditions such as allergies, irritation, and acne. It may also remove the excess of fat, provide you with anti-aging skin benefits, and help with the healing of wounds and cuts.
Allergies and Skin Irritation
A cream with bentonite clay reduced eczema and corticosteroid use in 76% of cases in a trial on 33 people with job-related, uncontrolled hand eczema .
Applied on the skin, bentonite clay may help those suffering from acne by sucking up the fat that clogs the pores and killing infectious bacteria. A commercial mask with a similar clay reduced the number of acne lesions in a clinical trial on almost 200 people [60, 61+, 4, 62].
An anti-aging cream with bentonite clay retained water and protected human skin tissues from UV radiation .
Synthetic materials combining bentonite clay and antimicrobial drugs are being researched as wound dressings. They improved wound closure and killed infectious bacteria without damaging skin cells [64, 65, 66].
3) Protects the Teeth
Bentonite clay is a frequent ingredient of natural tooth-cleaning products, claimed to increase mineral content in the teeth. Limited research supports these claims. A complex of bentonite clay with a fluoride salt (titanium tetrafluoride) reduced mineral loss in sheep enamel [71+, 72].
Bentonite clay is often added to dental glue to improve its strength. While bentonite binds easily to enamel, only modified bentonite (attached to polymers) can bind to dentin strongly enough to be used in dental glue [73, 74, 75].
Microparticles of bentonite clay attached to curcumin, a natural antibacterial, killed a microbe that causes cavities (Streptococcus mutans) and prevented it from forming biofilms on a piece of enamel .
4) Supports Gut Health & Balances Your Microbiome
A healthy gut lining helps you digest food, take up nutrients, and fight off infections. A damaged barrier, impaired enzyme activity, or microbiome imbalances can lead to digestive issues [77+].
In a clinical trial on over 500 people with irritable bowel syndrome (IBS), bentonite clay (3 g, 3x/day) improved discomfort only in those with constipation-predominant IBS, possibly by binding to the bowel lining and reducing pain. In pigs and mice with IBS, it reduced inflammation by adsorbing cytokines and blocking their production [78, 79, 80].
Interestingly, bentonite clay has also been used to improve diarrhea since centuries, possibly because it absorbs microorganisms, toxins, and water in the bowel. In an old study on 35 people, this clay (2 spoonfuls 3x/day) quickly relieved diarrhea, stomach pain, nausea, and lack of appetite [81+].
Henoch-Schönlein purpura is a disease involving blood vessel inflammation that often damages the gut lining. In a clinical trial on 58 children with this condition, bentonite clay (3 g, 2x/day) protected their gut barrier .
- Increased the abundance of the “good” bacteria that promote digestion while reducing the “bad” bacteria [80+, 77+, 84+, 90]
- Restored imbalances caused by high-fat diets by lowering obesity-promoting bacteria [91, 92]
To sum it up, not only does bentonite clay have the potential to boost your nutrient status and digestive enzymes, but it might also restore your gut microbiome. Clinical trials confirmed that it improves constipation-IBS.
5) May Aid Weight Loss
In rats fed a high-fat diet, it increased fat excretion and reduced the growth of obesity- and inflammation-promoting bacteria. Plus, bentonite clay reduced weight gain, blood fat levels, and fat buildup in the liver [93, 91, 94].
Additionally, in an observational study on 49 people, a weight-loss program combining a low-calorie diet with a cleanse supplement containing bentonite clay reduced weight and blood fat levels. However, the exact contribution of bentonite clay to weight loss in this study is unclear .
6) May Relieve Allergies
In a clinical trial on 20 people allergic to dust mites, a single dose (0.28 mL/nostril) of a spray with bentonite clay relieved nasal congestion and inflammation (rhinitis) within 60 – 90 minutes .
7) Overactive Thyroid
Bentonite clay can bind to the thyroid hormones T3 and T4. This reduced their blood levels and overactive thyroids symptoms in rats and mice. But people with low thyroid function should be very cautious with bentonite clay .
8) Kills Viruses and Bacteria
Bentonite clay killed a broad range of bacteria in cell-based and animal studies, including those that cause:
- Diarrhea and food poisoning [98, 99+ 100, 101, 102, 103]
- Skin infections [98, 99+, 103]
- Stomach ulcers 
- Antibiotic-resistant infections 
- Infection of other tissues by gut bacteria 
- Plague [99+]
Bentonite clay adsorbed viruses – including those causing the common flu, dengue, and pink eye (conjunctivitis) – and, in some cases, reduced their capacity to cause diseases. This opens up the possibility of using it to fight viral infections in humans [106, 107, 108, 109, 110].
9) May Fight Cancer
In cell-based studies, bentonite killed the following cancer types by reducing cell growth and survival:
However, it increased the growth of lung cancer cells in one study .
10) May Prevent Waste Buildup in the Body
Creatinine, urea, and uric acid are three waste products that may build up in the blood in people with kidney damage because they are mostly flushed with urine. In rats, bentonite clay adsorbed these substances and prevented them from reaching the bloodstream [117, 118, 119].
Limitations and Caveats
Additional limitations of some studies included:
- Using bentonite clay in multi-ingredient supplements [57+, 62, 95]
- Not including a control group [95, 57, 62]
- Combining bentonite clay with a low-calorie diet 
The benefits of bentonite clay on heavy metal toxicity, skin aging, wound healing, tooth and gut health, overactive thyroid, bacterial and viral infections, cancer, and waste product elimination have only been tested in cells and animals. Studies in humans are needed to validate them.
Funding and Conflict of Interest
Drug Delivery Systems
Bentonite clay can be modified into synthetic materials (with polymers). These can be used as improved delivery and slow-release systems of drugs for [122+]:
- Cancer (such as doxorubicin, paclitaxel, and tamoxifen) [123, 124, 125, 126, 127, 128, 129, 130, 131]
- Infections (ciprofloxacin, curcumin, praziquantel) [132, 133, 134]
- Sunscreen protection (Eusolex, NeoHeliopan, zinc and titanium oxides) [135, 136]
- Glaucoma (betaxolol) 
- Psychiatric disorders (olanzapine) 
- Impotence (sildenafil) 
In the case of sildenafil, bentonite clay also helped mask its unpleasant taste .
How to Use Bentonite Clay
Bentonite clay normally comes as a clay powder. You can prepare a paste simply by adding water until you achieve the desired, yogurt-like consistency. To make sure your clay is not too diluted, add water to the powder bit by bit, letting the clay soak it up gradually.
Note: Bentonite clay might react with metal objects and lose effectivity, although studies are lacking to confirm this claim. To stay on the safe side, consumers and manufacturers often recommend using ceramic or glass bowls and plastic or wooden spoons.
You can experiment with bentonite clay powder for external use at home almost endlessly. Here are some ideas:
- Soothing skin paste: apply a paste on burns, bites, and rashes, and leave until it dries.
- Face mask: make a paste and leave on the skin for 10 – 20 minutes.
- Hair mask: apply a paste on the hair from root to tip 1x – 2x/week. You can add a bit of apple cider vinegar with water and even mix in a couple of drops of your favorite hair-nourishing oil.
- Armpit detox: apply a paste on the armpits to remove toxins.
- Skin-softening bath: add bentonite clay to your bath water to soften the skin and get rid of built-up skin toxins.
- Homemade soap: this is slightly more complicated, but you can combine bentonite clay with oils and lye to make soap for oily skin.
- Tooth-brushing powder: clean your teeth with bentonite clay to remineralize them, make them whiter, and kill bacteria.
If you prefer, you can buy ready-to-use bentonite clay versions of most of these DIY remedies.
You can also take bentonite clay by mouth to remove toxins and help digestion. Dissolve 0.5 – 1 teaspoon bentonite clay in 1 cup of water and drink 1x/day. Most clinical trials used up to 3 g/day. In this case, you want to be absolutely certain that you have food-grade clay. Bentonite clay supplements are also available in tablets and capsules.
Finally, you can mix bentonite clay with water and give it to your pets to improve digestive issues or poisoning. The dose will depend on the size of the animal. Consult your vet first if your pet has serious health issues, though.
Bentonite Clay Side Effects & Cautions
Bentonite clay (1.5 – 3 g/day) is relatively safe and only caused mild digestive symptoms (flatulence, stomach pain, bloating, constipation, diarrhea) in less than 10% of people taking it for 2 weeks. Half this dose didn’t cause any adverse effects in children. In both adults and children, it didn’t reduce the uptake of minerals and vitamins [140, 141, 142].
In turn, excessive oral doses may cause nutrient deficits. A 3-year-old girl who was given adult doses and a cat that ate litter containing this clay developed severe potassium deficit with vomiting, constipation, sleepiness, and weakness [143, 144].
Similarly, topical bentonite clay was generally safe in clinical trials. Only one person developed mild, temporary skin redness from a bentonite clay lotion .
High exposure to bentonite clay dust from mines and steel plants was associated with an increased incidence of respiratory diseases and cell damage in several studies. However, its potentially toxic impurities (quartz, kaolin, perlite) could have contributed to these effects [145, 146, 147+, 148].
A dental assistant had a severe corneal inflammation with reduced vision and sensitivity to light after a tooth-polishing paste with bentonite clay came in contact with her eye [149+].
Although its use during pregnancy or breastfeeding is not investigated in women, bentonite clay didn’t reduce mineral uptake or utilization in pregnant rats .
Bentonite clay may bind to some drugs, especially those positively charged, and prevent their transport into the bloodstream. Some of these drugs include:
- Antibiotics (such as tetracycline, trimethoprim, and rifampicin) [151, 152, 153, 154, 155, 156, 157]
- Drugs for heart disease (digoxin, quinidine) [158, 159]
- Antiallergic drugs (promethazine, chlorpheniramine) [160, 161]
- Stimulants (caffeine, amphetamine) [162, 163+]
- Drugs for psychiatric disorders (lithium) 
- Drugs for respiratory diseases (theophylline) [163+]
- Sedatives (propoxyphene) [163+]
- Antidiabetic drugs (metformin) 
Consult your doctor before using bentonite clay internally if you take medication.
Best Bentonite Clay
There are two main types of bentonite clay: sodium and calcium [3+]:
- Sodium bentonite clay absorbs more water. While this makes it more effective at removing toxins, the clay is very alkaline and can be too aggressive to the skin. By mouth, it may cause constipation.
- Calcium bentonite clay takes up more electrolytes, making it more effective in case of poisoning. This clay is less alkaline and absorbs less water than sodium bentonite.
Although it’s generally assumed that only calcium bentonite can be used internally, both types are safe if they come from reputable sources. It’s important to buy pure/clean bentonite with a high montmorillonite content and free of toxic contaminants.
For instance, the FDA issued warnings against two bentonite clay masks (Bentonite Me Baby and Best Bentonite Clay) after laboratory tests found unsafe levels of lead.
If you are planning to take it by mouth, make sure it’s food-grade bentonite clay. The one for external use may contain additives that shouldn’t be ingested.
Most people bought bentonite clay to apply it on the skin, especially as face masks. The reviews were generally positive and users reported that the clay removed fat and toxins and softened their skin. People using it for scars, bug bites, and spots were equally satisfied.
Adverse effects were rare and only a few users complained that the clay made their skin itchy.
People used bentonite clay internally mainly for detox, digestive issues, and infections. Users were generally satisfied with its effects and mild taste, with only a few reporting that it didn’t work for them.
Importantly, a lot of the bad ratings came from people taking in a bentonite clay product meant for external use only. They generally complained about its taste, lack of effects, and additives.
Buy Bentonite Clay
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Bentonite is an important healing clay. Its unique structure gives it a negative charge and layers into which it trap toxins, fats, and water. By doing so, it removes these substances from the skin when used externally. Internally, it binds toxins in the gut and helps the body detox them.
It also aids digestion, protects the teeth and may help fight infections, relieve allergies, and support weight loss.
Bentonite clay normally comes as a clay powder you can mix with water. It’s easy to make a paste and use it as a skin-soothing ointment, face and hair mask, or armpit detox. Plus, you can add it to your bath water or brush your teeth with the powder. Ready-to-use skincare products with the clay are also available.
You can also prepare a detox drink with food-grade bentonite clay. Capsules or tablets are another option for oral use. Be sure to consult your doctor if you take medication (as bentonite clay can bind to it) or are pregnant before using it internally.