DE powder is diatomaceous earth, a fine, off-white powder made from the fossilized remains of tiny aquatic organisms called diatoms. These microscopic single-celled algae accumulated in lakes and oceans over millions of years, and their skeletal remains compressed into a soft, chalky mineral deposit that can be ground into powder. It’s composed of 70 to 96 percent silica, with small amounts of aluminum oxide and iron oxide. You’ll find it sold for pest control, as a food-industry additive, and in pool filtration systems.
What DE Powder Is Made Of
Diatoms are phytoplankton, tiny plant-like organisms that build their cell walls (called frustules) out of silica, the same compound found in sand and quartz. When diatoms die, those glassy shells sink and pile up on the beds of lakes, rivers, and oceans. Over geological time, these deposits harden into a lightweight, porous rock called diatomite. Mined and milled into powder, it becomes the product sold as diatomaceous earth.
Under a microscope, DE looks like a collection of intricate, hollow cylinders and discs riddled with tiny pores. That porous structure is what gives the powder its unusual properties: it’s extremely absorbent, very lightweight, and feels abrasive at the microscopic level despite feeling soft between your fingers. The silica in DE is primarily amorphous, meaning it lacks the rigid crystal structure of quartz. This distinction matters for safety, as crystalline silica is far more hazardous to the lungs than amorphous silica.
Food Grade vs. Filter Grade
Not all DE powder is the same. The two main types differ dramatically in their crystalline silica content, which determines how they can safely be used.
- Food grade contains up to 2 percent crystalline silica. This is the type used as an insecticide, as an anti-caking agent in grain storage, and in dietary supplements. The FDA classifies food-grade DE as Generally Recognized as Safe (GRAS) for use in food processing.
- Filter grade (pool grade) contains around 60 percent crystalline silica. It’s been heat-treated (calcined) to harden the particles for use in swimming pool filters. This type is not safe to breathe, ingest, or use around the home for pest control.
If you’re buying DE for any household purpose, food grade is the only appropriate choice. The packaging should clearly state “food grade” on the label.
How It Works as a Pest Control Powder
DE kills insects through a purely physical process, not a chemical one. When an insect crawls through the powder, the microscopic sharp edges of the diatom shells scratch and damage the waxy outer layer of the insect’s exoskeleton. At the same time, the powder absorbs the oils and fats from that protective coating. Without its waterproof barrier, the insect loses moisture rapidly and dies from dehydration. This process typically takes anywhere from a few hours to several days depending on the insect.
Because it works mechanically rather than chemically, insects can’t develop resistance to DE the way they can with traditional pesticides. It’s commonly used against ants, bed bugs, fleas, cockroaches, and other crawling insects. The powder needs to stay dry to be effective. Once it gets wet, it clumps together and loses its abrasive, moisture-wicking properties until it dries out again.
Using DE Powder at Home
For pest control, apply a thin, barely visible layer of food-grade DE in areas where insects travel: along baseboards, behind appliances, around door frames, and in cracks or crevices. A thick pile is actually less effective because insects will walk around it rather than through it. A light dusting is all you need.
The most important precaution is avoiding inhalation. Even food-grade DE can irritate your lungs, nose, and throat when airborne. Wear a dust mask when applying it, and keep children and pets out of the area until the powder settles. Avoid using it in high-traffic areas where foot traffic will kick it into the air repeatedly. OSHA requires that exposure information and the potential for lung irritation be reported on product safety data sheets, even for the amorphous form.
Health Claims and What the Evidence Shows
DE powder is marketed online as a supplement for lowering cholesterol, strengthening hair and nails, and “detoxifying” the body. The evidence behind these claims is thin. The most commonly cited study involved just 19 participants who took 250 milligrams of DE three times daily for eight weeks. Their total cholesterol, LDL cholesterol, and triglycerides dropped during the study and remained lower four weeks after they stopped taking it. While that sounds promising, a single study with 19 people and no control group is far too small to draw reliable conclusions from.
The supplement angle is largely built on the idea that DE provides dietary silica, a trace mineral involved in bone and connective tissue health. Your body does use small amounts of silica, but most people get adequate amounts from food. Whole grains, leafy greens, and beer are all meaningful sources. There’s no strong evidence that supplementing with DE offers benefits beyond what a normal diet provides.
Other Common Uses
Beyond pest control and supplements, DE powder has a surprisingly wide range of industrial and household applications. In the food industry, it’s used as an anti-caking agent to keep powdered products from clumping. It’s also widely used in filtration, where its porous structure makes it effective at trapping fine particles in everything from beer and wine to cooking oils and water treatment systems.
Around the house, some people use food-grade DE as a deodorizer in shoes or trash cans, a mild abrasive in homemade cleaning products, or a moisture absorber in stored grains and pet food. Its ability to soak up liquids and odors comes directly from that same porous diatom structure that makes it useful as an insecticide. Because it contains roughly 96 percent silica, it also functions as an effective and lightweight heat insulator in some industrial settings.