Basic Research Leads to Market’s First All-Natural, EPA-Registered Insect Repellent

When Michael Roe arrived at NC State University almost four decades ago, he didn’t have grand plans to invent products or launch startups. 

Today, Roe holds the title of William Neal Reynolds Distinguished Professor in the Department of Entomology and Plant Pathology, as well as over 60 published patents. And his research has helped multiple potentially lifesaving products reach the market. Most recently, a groundbreaking DEET-free insect repellent that’s sold by the startup company Mimikai, which licenses IP from NC State. 

“I was hired to do basic science,” Roe says. “So it just shows you the importance of academic research.”

Anyone who’s spent significant time just about anywhere in the South — especially along the Gulf Coast, from Florida through Texas — during the spring and summer months likely knows how bad the mosquitoes can get as the heat and humidity start ramping up. Even Americans living as far north as Alaska still have to suffer through a mosquito season, though. So, essentially, there’s no escape. 

And mosquitoes aren’t just annoying; they can transmit malaria, Zika, encephalitis, West Nile virus and other serious diseases.

The above-average amounts of rainfall that the Research Triangle region and beyond have received this season, combined with heat indices regularly in the triple digits, have created ideal conditions for mosquitoes to thrive here locally. 

“Most insects, in order to grow and develop, need two things: heat and moisture. And we’re seeing more of both,” Terri Billeisen, a turfgrass entomologist at NC State, recently told WRAL News. Billeisen went on to say that activity usually spikes one or two days after a significant rainfall event. “That’s when they really explode,” Billeisen said. 

Meanwhile, on top of mosquitoes, outdoors enthusiasts also have to keep an eye out for ticks, which can infect humans with Rocky Mountain Spotted Fever or Lyme disease. In 2024, mosquitoes and ticks accounted for over 900 cases of disease or illness reported statewide, according to the N.C. Department of Health and Human Services. Left untreated, West Nile virus, malaria, Lyme disease and Rocky Mountain Spotted Fever can all be fatal.

Now, for the first time ever, consumers have a completely natural repellent option to purchase for trusted personal protection against mosquitoes and ticks.

Bug Off, DEET

In the Pacific theater of WWII, soldiers on both sides of the battle constantly had to fight more enemy than one. Malaria and dengue fever — two mosquito-borne diseases — ravaged the armies of both Japan and the United States. 

On the U.S. side, 48,000 cases of malaria were reported across the Southwest Pacific in 1942 alone. Overall, more than 60% of all troops who fought in the Pacific caught malaria, and another 5% came down with dengue fever, which means roughly 1.2 million soldiers were afflicted with one or both of the diseases at some point.

In response, the U.S. Army introduced DEET (chemical name, N,N-diethyl-meta-toluamide) in 1946. Samuel Gertler, working for the USDA on the Army’s behalf, first synthesized the chemical compound two years prior. By 1957, DEET was registered for use by the general public.

While undoubtedly effective, DEET has a distinctive odor that some people find unpleasant. 

“Smell is also a very important aspect to consider,” Roe says.

Plus, DEET can corrode certain clothing materials and leave consumers with sticky-feeling skin. And even though it’s generally safe to use bug repellents containing DEET on anyone aged two months and up, mild skin irritation isn’t uncommon, especially when using products with higher concentrations of the chemical.

In the decades since it hit the market, several companies have come out with DEET alternatives that offer similar protection without the same smell or feel. DEET’s leading alternatives largely rely on active ingredients of either picaridin or oil of lemon eucalyptus, with a compound called IR3535 representing a smaller share of the market.

“Many in the public just don’t want to apply artificial compounds to their skin or on their children,” Roe says.

Each DEET alternative has other drawbacks of its own, too; namely, none has been proven to offer protection against biting insects for quite as long as most DEET-based products. And since they’re all synthetic, they have the potential to irritate the eyes and skin.

Mimikai’s repellent leverages the active ingredient undecanone — a naturally occurring chemical compound found in tomatoes, bananas and other fruits. The company’s groundbreaking product has been certified by the EPA to protect against mosquitoes for up to eight hours and against ticks for up to four hours.  

“We’re actually proven as effective as DEET, and we have the lowest toxicology of any of its alternatives,” says Stephanie Watson, co-founder and president of Mimikai. “So there’s no issue with eyes, and we’re very safe and clean on the skin.”

Beginnings in Biomimicry

Watson, a successful businesswoman from Australia, had developed plenty of consumer products — cleaning products, toys and water bottles, just to name a few — before she even knew of Roe, the inventor, entrepreneur and NC State entomology professor who grew up in Bayou Country and went on to earn bachelor’s, master’s and doctoral degrees from Louisiana State University. 

After selling her previous startup to Seventh Generation, Watson was looking for a brand-new kind of challenge. She says one thing she’d never tried to tackle was developing a formulation from scratch. And whatever she pursued next, she wanted it to focus on a product that would be environmentally friendly. 

“I was looking at a bunch of different product categories, and I couldn’t figure out why insect repellents were so toxic,” Watson says. 

A plethora of other skin care products were already available for the more conscientious consumer, but when it came to bug sprays, hardly anything new had come to compete with DEET.

“It just seemed so strange,” she says.

Around the same time she started looking into the insect repellent industry, Watson says she  also happened to be “kind of geeking out on” a concept called “biomimicry.” 

“That’s the practice of looking at nature to inspire innovation and product development,” Watson says. 

While surfing the web one day, Watson came across a news release that mentioned both biomimicry and repellents. Included in the release was Roe’s contact information. So she called up his lab. 

“He and I had an awesome conversation for, like, two hours — about nothing to do with repellents,” she recalls. 

Before long, she was on a plane to Raleigh to visit Roe’s lab space on campus. Going on seven years later, the unlikely pair have become “really good mates,” who email each other on a weekly basis, Watson says. 

In between now and then, Watson and Roe give due credit to the support they’ve received from NC State. Roe says that their company would not be where they are today without the Office of Research Commercialization. And Watson says they also have the Wolfpack Investor Network to thank, as one of their earliest investors.

“Mimikai has had a really long, strong relationship with NC State,” Watson says.

Mimikai’s Origins in Roe’s Research

You don’t have to look long and hard to find a nod to the startup’s beginnings in biomimicry. 

“Mimikai means mimicking nature,” Roe says.

But Roe’s journey from what he describes as a chance discovery in his lab to having an EPA-registered insect repellent on the market was neither short nor easy. This story begins near the turn of the 21st century. 

By the early 2000s, other researchers — including some in Roe’s same department at NC State — had already discovered that undenacone could be used in agricultural pest control. 

“When plants make this compound, insects don’t attack them,” Roe says. “But the focus of the literature at the time was on the use of this chemistry for controlling agricultural pests.”

No one had yet considered whether the same compound could repel insects from humans.

“That was the ‘Aha’ moment. Maybe it could be used in a different way than the whole world was thinking,” Roe says. “Here’s a compound that plants make to prevent insects from eating the plants, and I discovered that the same compound can keep mosquitoes and ticks from feeding on humans.”

The very first patent Roe published related to this work pre-dates Mimikai’s recent product launch by more than a quarter-century. So what took so long, you might wonder?

In addition to the usual bumps in the road that every aspiring entrepreneur will face, the EPA’s registration process played a significant role. But Roe and Watson believed the agency’s endorsement of their repellent would turn out to be well worth it. 

“To sell a legitimate insect repellent that everyone is going to respect, you need an EPA registration,” Roe says.

We didn’t want to just be seen as another essential oil.

Watson says they knew Mimikai had to prove its product’s efficacy. And that proved to be “really tough,” she says.

Most personal care products — like lotion or sunscreen — fall under the FDA’s purview. Insect repellent, on the other hand, is subject to the more stringent approval of the EPA. 

Plenty of companies have released new brands of bug spray that are merely off-the-shelf formulations sold under a different name and in fresh packaging. But none of those formulations contained a novel active ingredient, nor did they register with the EPA. Rather than putting in the required effort, previous hopeful competitors chose to roll the dice on products that they couldn’t guarantee to offer protection for as long as DEET.

Mimikai wasn’t about to take that gamble. 

“We wanted to make sure that we got a full Environmental Protection Agency registration,” Watson says. “We didn’t want to just be seen as another essential oil.”

Making it to Market

It’s neither easy nor quick to receive the EPA’s blessing to label your product as certified to repel insects for as long as your packaging claims. Approval takes time, along with plenty of trial and error. 

“The EPA has very strict guidelines on how to evaluate whether something is a repellent or not,” Roe explains. “It has to be done by a third party that doesn’t have a vested interest in the outcome, with specific protocols on how the research is conducted.”

Shortly after Watson teamed up with professor Roe, she recruited a pair of seasoned chemists to help formulate the product. 

Between the two of them, the chemists had developed practically every skincare product imaginable; again, however, those products all shared one major difference. They were subject to the approval of the FDA — not the EPA. 

Little did the product development team know what lay in store.

“Every time we changed an ingredient in the formulation, we had to test it again to make sure the efficacy was on track,” Watson says. 

For example, whenever they added a fragrance or emulsifier, the team had to test its repellency in Roe’s lab at NC State. Even small changes in percentages can significantly affect how long a repellent lasts. 

That’s sort of the secret sauce to all of this. Finding these kinds of things out doesn’t happen every day.

Early on, Watson says they struggled to find a way to formulate the spray without it separating “like a salad dressing.” Above all, this meant that if consumers forgot to regularly shake the can prior to application, it could affect the repellent’s efficacy. 

“So we had to figure that out,” Watson says. 

The next big challenge was figuring out how to make the active ingredient last as long as DEET — which comes down to spatially keeping the active ingredient, undecanone, around someone for the duration of repellency. What made that particularly tricky, Watson says, was that undecanone naturally tends to evaporate very quickly. 

“So we had to try and formulate it with different inert ingredients to make it stay around a person,” Watson says. “And once we’d figured that out, Mike and I co-authored patents on that discovery. Because what we discovered was really unique — how to get the most out of the active ingredient.”

Only time will tell just how much financial return on investment Mimikai and, in turn, from royalties, NC State could one day see. But, regardless, Roe is confident that basic research remains invaluable.

“That’s sort of the secret sauce to all of this. Finding these kinds of things out doesn’t happen every day,” Roe says. “That’s why you have all these labs on our campus that are doing all types of research, which maybe some people don’t appreciate, because it’s only every once in a while you discover something like this.”

Mimikai’s line of all-natural insect repellent sprays is available for purchase on its website, as well as on Amazon and in Credo Beauty and other select retailers. Watson is currently working to get their products into more big-box stores across the U.S., with plans to eventually enter international markets. 

In 2024, the insect repellent market generated over $376.9 million in revenue in the U.S. alone. According to Horizon Grand View Research, the industry could grow to annual revenues in excess of $540 million by 2030.

“This is not a small market,” Roe says. “So there’s a huge potential for the university to benefit as well as Mimikai.” 

With the right resources and support, who knows what researchers at NC State and across the country might discover next?