Andrew Rothaus of Longsleeve: “If you feel strongly enough that you can create something good in the world, it’s your responsibility to work until you’ve gotten there”

When I was considering entering this industry, one of the first pieces of advice I received was from a retired Estée Lauder executive. She was brutally honest with just how hard the industry is from all angles — marketing, manufacturing, regulatory, etc. It was important for me to hear because it mentally prepared me for the hurdles […]

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When I was considering entering this industry, one of the first pieces of advice I received was from a retired Estée Lauder executive. She was brutally honest with just how hard the industry is from all angles — marketing, manufacturing, regulatory, etc. It was important for me to hear because it mentally prepared me for the hurdles I’m still learning to navigate.

As a part of our series about business leaders who are shaking things up in their industry, I had the pleasure of interviewing Andrew Rothaus.

Andrew Rothaus is an inventor, investor, and entrepreneur. He graduated summa cum laude from Yale in 2011 before heading to Wall Street as a derivatives trader. In 2016, he left his trading career to attend Harvard Business School, where he founded Longsleeve (, the company disrupting how you protect yourselves from insects.

Thank you so much for doing this with us! Before we dig in, our readers would like to get to know you a bit more. Can you tell us a bit about your “backstory”? What led you to this particular career path?

Currently, my singular focus is to create cosmetic-grade, scientifically-proven insect repellents and other products that will protect you outside of the house.

Growing up, however, I was determined to break into finance. So I did everything as prescribed — studied for grades, networked for internships, got into the office early and left late — and I got a job as a derivatives trader at a big commercial bank. I was running the US trading desk by my 25th birthday. I did it…but I was unhappy. I would lay in bed every night dreading my alarm clock and wake up every morning with low enthusiasm.

While I worked on the trading desk, however, I began investing in alternative assets — Broadway shows, depressed real estate, agriculture, and beverage startups. I realized that I found joy in the process of building something from scratch. So I applied to business school.

When I got to HBS, my brother asked for some help with a long-lasting hair product he was developing using proven medical technology. At the same time, my Miami-based sister-in-law learned that she was pregnant during the peak of the Zika crisis and began to feel unsafe outside of her home. It was so hard to know what repellent products actually worked, which ones were safe for her and the baby — and none of them felt good to put on.

I asked my brother if the long-lasting technology from his hair product could work on the skin, and he thought it was likely. So we went to the lab and bonded our proprietary molecule to fluorescein, which glows under UV light. Then, we applied the product to volunteers’ feet, and these volunteers (myself, two friends, and my dad) went about their normal lives — showering, exercising, etc. After three days, foot fluorescence remained at over 50%. It also didn’t feel greasy on the skin or smell bad.

This was my “a-ha!” moment. I wondered: what would happen if we bonded our technology to insect repellent molecules instead of fluorescein?

We went back to the lab and tried numerous natural repellents — citronella, eucalyptus, neem oil, etc. — and began applying to our own skin during buggy nights. We asked a few friends to do the same, and we all had the same impression… it worked!

Excited, we took it a step further and hired an independent mosquito lab to conduct arm-in-cage testing, where people stick their arms in cages full of hungry mosquitoes and measure how many mosquitoes land and bite. The results blew us away. Our product outperformed DEET… by a lot. After 8 hours, DEET was totally ineffective, but we maintained 100% efficacy. After 24 hours, we still maintained 99% efficacy. When we asked to extend the tests to 72 hours, we were told that such a long test had never even been designed before.

Thus, Longsleeve was born. The next year, we won Harvard’s New Venture Competition. And this year we received a grant from the National Science Foundation to further our development and accelerate our path to market.

Can you tell our readers what it is about the work you’re doing that’s disruptive?

There are two arenas in which we’re disruptive — existing markets and humanitarian markets.

I’ll start with existing markets. Insect repellent technology is old — I collect vintage insect repellents, and I have DEET products from the 1950s. Insect repellent smells bad. It feels bad. It absorbs into your bloodstream through the skin. Many of the claims to consumers are vague, misleading, and use regulatory loopholes to avoid doing real testing. When was the last time you felt good applying insect repellent?

Longsleeve addresses every single one of those issues. We take safe, natural repellents that usually work for a short period of time, and create larger, slower-to-evaporate molecules that last longer on the skin, feel luxurious, don’t absorb into the bloodstream, and are more effective than DEET. We are totally upfront about our test results and procedures without making vague and unclear claims.

But the Longsleeve promise goes beyond delivering a more pleasant hike or day at the beach. Vector-borne diseases (malaria, dengue, Zika, etc.) are some of the most significant threats to global health, particularly for the world’s poorest people. In 2016 alone, malaria claimed the lives of over 445,000 people, many children under 5 years old.

Given rapid globalization, epidemics in any part of the world can travel almost anywhere in a matter of hours. And, as we’ve seen with Ebola, Zika, and, most recently, COVID-19, vaccine development lags several months to years behind catastrophe. Thus, focusing public health efforts on preventing transmission of illness is often a much more practical solution.

The use of body-worn repellents is promising, but this method has failed to meet its full potential due to adherence issues, particularly because products are only effective for a few hours and are unpleasant to use. Infection requires just a single exposure to a diseased vector, so there’s little room for error.

Longsleeve’s technology addresses these problems directly and could save billions of dollars that are otherwise being spent on costly, ineffective interventions by country governments and social institutions. Most importantly, Longsleeve has the potential to save millions of lives.

Can you share a story about the funniest mistake you made when you were first starting? Can you tell us what lesson you learned from that?

The first few months of starting a business is basically just making sure you use every mistake to learn a lesson.

My first mistake was believing everyone would want a 3-day insect repellent. With that assumption, we spent hundreds of hours figuring out the perfect formula, costs, and regulatory strategies. It was only after I had the solution outlined that I finally interviewed potential customers. Imagine my dismay when most initial customers said they didn’t want something that lasted 3 days, but something safe, natural, and better than DEET. So we realized that we had been putting all this work into making the wrong initial product. We’d be better suited focusing on bringing our active ingredients as low as possible and formulating a repellent that smelled good, felt good, had long-term positive results for skin, and was better than DEET. We learned that product design should always come after customer conversations.

We all need a little help along the journey. Who have been some of your mentors? Can you share a story about how they made an impact?

I’ve had a lot of help and found a lot of inspiration along the way, particularly within my own family.

My dad was the supportive force behind my choice to leave the finance path. As a doctor, he made a similar career choice by leaving a hospital position to build his own practice from scratch, solely because he wanted to be able to spend more time with his three young sons.

My sister-in-law (Kalyn) and my two adorable nephews (Tyler and Owen) are some of my biggest product inspirations — it was Kalyn’s experience as an expecting mother that inspired the idea in the first place, and we continue to focus heavily on developing products that are baby-safe. Keep an eye out soon!

Finally, my college roommate and best friend, Abraar, has had enormous impact as both a friend and mentor. He is painfully smart and has chosen to dedicate his life to public health. He’s quickly become a rising star in global health. When I first had the idea, he and I spent countless hours discussing the global health potential and crafting a plan. He and I won the New Venture Competition together, and he convinced me that this was a dream worth chasing.

In today’s parlance, being disruptive is usually a positive adjective. But is disrupting always good? When do we say the converse, that a system or structure has ‘withstood the test of time’? Can you articulate to our readers when disrupting an industry is positive, and when disrupting an industry is ‘not so positive’? Can you share some examples of what you mean?

One of the main features of many modern “disruptive” companies is that that they sell direct-to-consumer (DTC), when there used to be a distributor or other middleman. In most cases, this has had positive results by improving information and lowering costs to consumers for a myriad of products — mattresses, furniture, cosmetics, etc.

But sometimes, when a producer (either of information or products) has a direct and unfiltered line to the consumer, it results in the spread of misinformation or shoddy products. For example, while traditionally retailers would ensure that clinical tests and product claims were legitimate, the DTC model has allowed some firms to communicate unfounded claims to consumers. This issue has appeared frequently during the COVID-19 pandemic as sellers — protected beneath a corporate veil — market unproven products with dubious claims. The FDA and FCC don’t have enough resources to keep up. This is why it’s so important to buy from a brand you trust.

Can you share 3 of the best words of advice you’ve gotten along your journey? Please give a story or example for each.

When I was considering entering this industry, one of the first pieces of advice I received was from a retired Estée Lauder executive. She was brutally honest with just how hard the industry is from all angles — marketing, manufacturing, regulatory, etc. It was important for me to hear because it mentally prepared me for the hurdles I’m still learning to navigate.

And the hurdles mentioned above have, at times, made me question whether I made the right decision leaving my finance career. But I’m always reminded of advice I received from Jodi Gernon, the Director of the Arthur Rock Center for Entrepreneurship at HBS. The first year that Longsleeve applied to the Harvard New Venture Competition, we didn’t win. I was discouraged. I told Jodi that I was considering a return to finance, and she asked me “Why would you leave a lucrative job because it’s meaningless to return to a meaningless job because it’s lucrative?” I think about this a lot.

Finally, my brother, Alexander, was the first in my family to pursue entrepreneurship. He built a tech-based haircare company, Mounia Haircare, from the ground up — coupling scientific development and cosmetic formulation. When I was making the difficult decision to leave my finance career, Alexander’s words stuck with me: “If you feel strongly enough that you can create something good in the world, it’s your responsibility to work until you’ve gotten there.”

We are sure you aren’t done. How are you going to shake things up next?

We’re always thinking of what’s next. Our development roadmap is extensive and could cover the next decade if all goes to plan. We’ve already begun development on the next generation of long-lasting, non-absorbing sunscreens and antimicrobials that use similar long-lasting technology and cosmetic-grade formulations as our other products. You should also keep an eye out for our next-generation apparel technology — I can’t share too many details here, but it’s very exciting and should be launching within the next few quarters.

Do you have a book, podcast, or talk that’s had a deep impact on your thinking? Can you share a story with us? Can you explain why it was so resonant with you?

When I was at business school, I would make the 3+ hour drive from Boston-to-NYC and back nearly every other weekend. During those long drives, I devoured every single episode of How I Built This with Guy Raz. He interviews successful founders of both small and large companies, and they walk the listener through their entrepreneurial journeys from ideation to execution. Each car ride, I’d be inspired by the realization that most founders were totally normal people whose main assets weren’t just good ideas but the willingness to take a risk by focusing on one thing and being the best at it. I honestly think that, without those car rides, I may not have made the same choices that brought me here today.

Can you please give us your favorite “Life Lesson Quote”? Can you share how that was relevant to you in your life?

I’ve always been a baseball fanatic, a trait I owe to my grandpa who almost played professionally. In nearly any situation, he gave me the same advice: “Keep your eye on the ball.”

As a child, I used this advice as a literal tool to get better at hitting and catching a baseball. But I continue to apply it daily. We have hundreds of ideas for new innovations and products that leverage our proprietary technology and other technologies, but a successful founder needs to focus on executing one idea well in order to get there. We need to keep our eye on the ball.

Entrepreneurship is a long road, and it can be tempting to return to a consistent and relatively cushy paycheck. Entrepreneurs need to keep their eyes on WHY they made the choice in the first place.

You are a person of great influence. If you could inspire a movement that would bring the most amount of good to the most amount of people, what would that be? You never know what your idea can trigger. 🙂

I’m a huge believer in the potential of Universal Basic Income (UBI). To explain, I’d like to compare two periods of extreme innovation: The Industrial Revolution (1800s) and The Automation Revolution (today).

Progress and innovation during the Industrial Revolution obviously had some terrible initial side effects, such as poor labor conditions for factory workers. But the eventual widespread economic gains were undeniable as life expectancies rose, unemployment plummeted, labor conditions improved, and the middle-class grew rapidly. It’s easy to understand one reason why this happened — every new machine or process required growing numbers of both specialized and unspecialized workers to operate and maintain, providing continued jobs, growth, and stability.

The Automation Revolution is different. Many new software/AI innovations no longer create or even replace jobs across the skill spectrum — they unleash a double-edged sword of increasing productivity while eliminating jobs altogether. In this scenario, nearly 100% of productivity gains flow to the top, which is why we’ve seen such unprecedented polarization of wealth over the past few decades.

Just a few generations ago, you could work a normal 9–5 job to buy a house, buy a car, send your kids to college, and save for retirement. There was so much opportunity and growth that something like UBI just seemed lazy. But we’ve reached a point where gains aren’t shared with those who are unlucky enough to be born distant from innovation. There are tens of millions of young people around the country who feel hopeless… it doesn’t matter how hard they work because there are so few opportunities for growth. This feeling of hopelessness stands in stark contrast to the fact that country has never been more productive or more able to provide life’s basic necessities (food, shelter, healthcare) to its citizens through a UBI system.

How many would-be disruptors are stuck figuring out how to feed themselves? How many would-be entrepreneurs and innovators are afraid to leave low-wage jobs because they have no safety net? By reinvesting these immense productivity gains into actual people, we can unleash the full potential of human creativity and free enterprise.

How can our readers follow you online?

Join our mailing list on

@wearlongsleeve on Instagram & Twitter

Email us at [email protected]

This was very inspiring. Thank you so much for joining us!

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