Natural Over Nasty: Why DEET Doesn’t Belong on Your Horse

When the flies, mosquitoes, and midges start swarming in summer, horse owners naturally want to protect their animals. It’s tempting to reach for strong chemical repellents like DEET, especially when the bugs are relentless. But while DEET is widely used on humans, it’s not a safe or ideal choice for horses.

Here’s why DEET-based products can do more harm than good—and what safer, more effective alternatives look like.

What Is DEET?

DEET (short for N,N-Diethyl-meta-toluamide) is a synthetic chemical developed by the U.S. Army in the 1940s for use in jungle warfare. It's designed to block insect sensory receptors, making it harder for them to detect skin and sweat.

While DEET works reasonably well for humans, it was never designed for animals, especially large animals with delicate skin like horses.

Why DEET Can Be Harmful to Horses

1.  Toxic if Ingested or Absorbed

Horses groom themselves and each other—licking, nuzzling, and rubbing—which means DEET applied to the coat can end up in their mouths.

DEET is toxic when ingested, and repeated licking of treated areas can lead to drooling, vomiting, colic-like symptoms, and in rare cases, neurological issues.

2.  Skin Reactions and Burns

Horses have thinner, more absorbent skin than humans—especially around sensitive areas like the face, belly, and groin.

DEET can cause:

• Chemical burns
• Hair loss
• Dry, flaky skin
• Itching and inflammation

Horses prone to sweet itch or allergies are particularly vulnerable.

3.  Overwhelming Scent and Sensory Stress

DEET has a sharp, synthetic smell that can be distressing to horses.

Because horses rely heavily on their sense of smell to interpret their environment, strong chemical odors can affect their behavior, especially in the arena or on the trail.

4.  Sweat Strips It Away

DEET is water-soluble and doesn't hold up well against sweat or rain.

Horses sweat much more than humans, meaning the repellent breaks down quickly—requiring frequent reapplication and increasing exposure risk.

5.  It’s Not Necessary

Many natural alternatives are just as effective at repelling flies, mosquitoes, midges, and ticks—without the risk of toxicity or skin irritation.

Natural Alternatives That Are Safer for Horses

At a time when diseases like West Nile Virus and sweet itch are a growing concern, it’s important to repel insects without compromising your horse’s health. Natural ingredients like the ones in Fly Free Healing Balm offer plant-based protection that’s both gentle and powerful:

Neem Oil: Disrupts insect feeding and reproduction. Also supports skin healing.

Coconut Oil & Beeswax: Creates a breathable, protective seal that locks in moisture and keeps insects out.

Our unique blend of essential oils: Cool, soothe, reduce itching and repel flies, mosquitoes, ticks, culicoides and other biting insects naturally, including one of the few essential oils recognized by the CDC for mosquito control.

Calendula and Aloe Vera: Calm skin, reduce itching, and support natural healing.

Unlike DEET, these ingredients are:

DEET may seem like a strong solution, but it’s too strong—and often dangerous—for horses. Between the risks of toxicity, skin damage, and behavioural stress, it simply isn’t worth the risk.

Thankfully, nature provides a better way. With healing balms like Fly Free, you can give your horse safe, lasting relief from summer pests, while also soothing the skin and avoiding harsh chemicals altogether.

Protect your horse the gentle way—because health and comfort should never be compromised.

Our Fly Free balms are

Try it now and ditch the DEET for good!