Is Diatomaceous Earth in Shampoo Really Effective for Killing Fleas?

While at SuperZoo this past year a veterinarian asked me if using Diatomaceous Earth (DE) in shampoo was effective. 

It all goes back to understanding how Diatomaceous Earth works and how it doesn't work! Let me explain.

When it comes to natural remedies for flea control, Diatomaceous Earth is often at the forefront of recommendations. It’s commonly found in various pet care products, including shampoos, with claims that it can kill fleas on contact.

But how effective is DE in a shampoo formulation, really? Is it a genuine solution, or just another case of clever marketing hype? Let’s break it down.

What is Diatomaceous Earth and How Does It Work?

Diatomaceous Earth is a fine, powdery substance made from the fossilized remains of tiny aquatic organisms called diatoms. These organisms have a high silica content, which gives DE its abrasive, microscopic sharpness. When fleas and other insects come into contact with DE, the particles can damage their exoskeletons, leading to dehydration and eventually death.

This natural method of pest control is highly effective in dry conditions because the DE needs to remain powdery to function correctly. However, the effectiveness of DE in shampoo formulations is far less certain, and here’s why.

The Problem with Diatomaceous Earth in Shampoo

1. It Needs to Stay Dry to Work: DE’s primary mechanism for killing fleas relies on its ability to remain dry and abrasive. Once it gets wet, as it obviously will in a shampoo, it loses its sharpness and, consequently, its effectiveness. The shampooing process also washes away the DE before it has a chance to do much damage to the fleas.

2. Insufficient Contact Time: For Diatomaceous Earth to work, fleas need to come into direct contact with it and stay in contact for a sufficient amount of time. In a shampoo, the DE is applied and rinsed off relatively quickly, leaving little time for it to affect the fleas. This rapid wash-off limits the potential for DE to be effective in killing fleas during a bath.

3. Particle Distribution in Liquid Form: DE is a fine powder, and in a liquid shampoo, it may not be evenly distributed. This means that even if DE could work in a wet environment (which it can’t), there’s no guarantee that it would reach all the fleas on your pet. The particles may settle or clump, reducing the likelihood of effective contact with fleas.

The Verdict: Hype or Help?

The inclusion of Diatomaceous Earth in shampoo formulations for flea control appears to be more about marketing than actual efficacy. While DE can be an effective natural flea killer when applied as a dry powder, the conditions required for it to work simply aren’t present in a typical shampooing process.

If your goal is to eliminate fleas, relying on DE in shampoo might not be your best bet. Instead, consider DE to create a flea-free environment for your pets when used correctly in other areas.

Here’s how you can use Diatomaceous Earth around your home and yard to keep your dog safe from pests.

1. Applying Diatomaceous Earth in the Yard

Fleas often start their invasion from the outside, making your yard the first line of defense. DE can be a great tool for controlling fleas and other pests in outdoor areas.

• Where to Apply: Focus on areas where your dog spends the most time. Pay special attention to shady areas where fleas thrive. If your dog has a favorite sniff area in the yard, avoid applying DE in those locations.
• How to Apply: On a dry day, lightly sprinkle DE across the targeted areas of your yard. Use a dust spreader for larger areas to ensure even coverage. It’s important to reapply DE after heavy rain or watering, as moisture reduces its effectiveness.
• Safety Tip: While DE is non-toxic, you should still avoid applying it on windy days to prevent inhalation by you or your pets. Wear a mask while applying. After application, allow the dust to settle before letting your dog back into the treated areas as the dust can be irritating to the respiratory system.

2. Using Diatomaceous Earth in Dog Bedding

Dog bedding can become a hotspot for fleas, and treating it with DE can help keep these pests at bay.

• Preparation: Wash your dog’s bedding thoroughly in hot water and 4-Legger shampoo to kill any existing fleas and their eggs. Dry it completely before applying DE.
• Application: Sprinkle a light layer of DE over the bedding and work it into the fabric. You can also place DE underneath the bedding or mattress, as fleas tend to hide in cracks and crevices.
• Frequency: Reapply DE every time you wash the bedding, and consider refreshing the layer of DE every few weeks to maintain its effectiveness.
• Safety Tip: Don't over apply DE in the bedding as you do not want it to cause respiratory irritation. If you can see powder after application, it’s too much or needs to be worked in more.

3. Treating Carpets and Rugs with Diatomaceous Earth

Carpets and rugs can also harbor fleas, especially if your dog spends a lot of time indoors. DE is a useful tool for treating these areas as well.

• How to Apply: Sprinkle DE on carpets and rugs, focusing on areas where your dog likes to rest. Use a broom or brush to work the DE deep into the fibers.
• Letting It Sit: For maximum effectiveness, let the DE sit for at least 24 hours, though longer is better if possible. This gives the DE time to dehydrate any fleas, larvae, or eggs present in the carpet.
• Vacuuming: After the waiting period, vacuum the treated areas thoroughly. Since DE can be hard on vacuum filters and bags, you may want to use an older vacuum or empty the bag frequently.
• Repeat as Needed: For active infestations, repeat the process weekly until the fleas are gone. For maintenance, a monthly application should suffice.

Additional Tips for Safe and Effective Use

• Quality Matters: Always use food-grade Diatomaceous Earth, especially when using it around pets. Non-food-grade DE can contain harmful chemicals.
• Avoid Direct Inhalation: Although DE is non-toxic, it can be irritating if inhaled. When applying it, try to avoid creating dust clouds, and consider wearing a mask for added protection. This is especially important for your dog since they are natural and avid sniffers. Your dog should not be present during application.
• Monitor Your Dog: While DE is generally safe, some dogs may have sensitivities. Watch for any signs of skin irritation or respiratory issues and consult your vet if needed.
• Do Not Apply Directly on Your Dog:  While many people say it is ok to apply DE directly on the dog, I recommend using it off the dog. It is very easy to over-apply DE and cause respiratory irritation as your dog will groom after application.

Bottom Line

While Diatomaceous Earth is a valuable tool in the natural pest control arsenal, its role in shampoo for killing fleas seems more like hype than help. Always consider the specific conditions and application methods when choosing flea treatments for your pet. Diatomaceous Earth can be a highly effective, natural way to control fleas and other pests around your dog when used in the right places, like the yard, bedding, and carpets.

By applying it strategically and safely, you can create a flea-free environment that helps keeps your dog comfortable and protected. Remember, consistency is key, so regular applications and monitoring are essential to keep fleas at bay.