Diatomaceous earth has one well-proven benefit: it kills insects through a purely physical process, without chemical pesticides. Beyond that, many of the health claims you’ll find online, from detoxing heavy metals to lowering cholesterol, have little or no solid evidence behind them. That doesn’t mean diatomaceous earth is useless, but it’s worth separating what’s established from what’s speculative.
Diatomaceous earth is a fine powder made from the fossilized remains of tiny aquatic organisms called diatoms. It’s composed primarily of amorphous silicon dioxide (silica) and can contain trace amounts of crystalline silica. The food-grade version is recognized as safe by the FDA for use in food processing, while the industrial-grade version (used in pool filters) contains much higher levels of crystalline silica and should never be consumed.
Non-Toxic Pest Control
This is where diatomaceous earth genuinely shines. It kills insects mechanically rather than chemically. The microscopic particles have sharp edges that damage the waxy outer coating on insects like ants, bed bugs, fleas, cockroaches, and earwigs. Once that protective layer is compromised, the insect loses moisture rapidly and dies from dehydration, typically within 24 to 72 hours of contact.
Because this process is physical, insects can’t develop resistance to it the way they can with chemical pesticides. It’s effective as long as the powder stays dry. Moisture renders it mostly useless, so it works best in dry indoor areas, crawl spaces, garden beds during dry weather, and along baseboards or cracks where insects travel. You can dust it lightly in areas where pets and children won’t inhale it, making it a practical option for households that want to avoid chemical sprays.
Silica as a Nutrient
Silicon is a trace mineral involved in collagen production, which is why some people take diatomaceous earth as a silica supplement. The logic is straightforward: collagen is a structural protein in your skin, hair, nails, bones, and connective tissue, and silica plays a role in its formation.
There’s some evidence that supplemental silica can make a difference. A 2007 study of 48 women with fine hair found that taking 10 mg of silicon daily for nine months strengthened their hair strands. Another study found that a bioavailable form of silica improved nail brittleness. However, these studies used specific silica supplements, not diatomaceous earth itself. How much silica your body actually absorbs from diatomaceous earth powder is unclear, and it may be far less than what you’d get from a purpose-made silica supplement or from silica-rich foods like oats, bananas, and green beans.
Cholesterol and Detox Claims
You’ll frequently see claims that diatomaceous earth lowers cholesterol and removes heavy metals from your body. The evidence for both is weak or contradictory.
An older, often-cited study suggested diatomaceous earth reduced cholesterol levels, but it was small, lacked rigorous controls, and hasn’t been convincingly replicated. A more recent randomized controlled trial published in Food & Function found that silicon from diatomaceous earth, incorporated into food products, did not alter triglyceride or insulin levels after meals. No changes in LDL or HDL cholesterol were reported either.
The detoxification claim is even more problematic. While diatomaceous earth can absorb heavy metals in a lab setting (its sorption capacity for cadmium and lead exceeds 70%), what happens in your digestive tract is different. A study in rats found that adding diatomaceous earth to feed at a dose of 5 grams per kilogram did not reduce accumulation of lead or cadmium in organs. In fact, lead levels in the liver, kidneys, and testes actually increased. The researchers concluded that the acidic environment of the stomach caused the diatomaceous earth to release metals it had absorbed, and that the diatomaceous earth itself contained measurable levels of lead and cadmium. Rather than pulling toxins out of the body, it may have added to the burden.
Use in Livestock and Pets
Diatomaceous earth is popular among farmers and pet owners as a natural dewormer and external parasite treatment. For external parasites like fleas, mites, and lice, it works through the same desiccation mechanism that makes it effective against household insects. Dusting it into poultry dust baths or lightly into pet bedding can help control external pests without chemicals.
For internal parasites, the picture is less encouraging. A University of Nebraska study on finishing cattle found that diatomaceous earth in feed did not significantly reduce parasitic eggs or coccidia compared to controls. After 28 days, parasite levels dropped across all groups (including those receiving no treatment), and steers fed conventional antiparasitic drugs had better outcomes than those given diatomaceous earth alone. There’s no strong evidence that it works as an internal dewormer in any species.
How People Use It
People who take food-grade diatomaceous earth orally typically mix it with water, juice, or a smoothie. There is no scientifically established dose for humans. Product labels often suggest starting with a teaspoon and gradually increasing, but these recommendations come from manufacturers, not clinical research. WebMD notes that there isn’t enough scientific information to determine an appropriate dosage range for children or adults.
If you decide to try it, only use food-grade diatomaceous earth. Industrial or pool-grade versions contain high levels of crystalline silica, which is classified as a known human carcinogen when inhaled. Even with food-grade products, avoid breathing in the dust. Amorphous silica is far less hazardous than crystalline silica, but inhaling any fine mineral dust can irritate your lungs and airways. Workers exposed to crystalline silica over years can develop silicosis, chronic obstructive pulmonary disease, and increased risk of lung cancer and kidney failure.
What’s Worth It and What Isn’t
As a pesticide, diatomaceous earth is genuinely useful. It’s effective, non-toxic to mammals at normal exposures, and works without contributing to insect resistance. For garden and household pest control, it’s one of the better natural options available.
As a health supplement, the picture is much murkier. The silica content is real, but absorption from raw diatomaceous earth powder is poorly studied. The cholesterol and detox claims aren’t supported by quality human research, and at least one animal study suggests the detox narrative may be backwards. If you’re specifically looking for silica’s potential benefits for hair, skin, and nails, a bioavailable silica supplement with actual dosing data behind it is a more evidence-based choice than spoonfuls of fossilized sediment.