Lessons from Serial Founder Joanna Shu: What She Learned the First Time and Applied at Cartwheel

Being a successful founder is rewarding and challenging. Now imagine taking on this role and responsibility again. Joanna Shu did just that. She’s the co-founder and CEO of Cartwheel Health, a medical device startup developing an innovative, non-toxic treatment for head lice.  

In this conversation with Startup Boston, Shu discusses why creating Cartwheel Health was personal for her, how humor is important in their branding, lessons learned from her first startup, and more. 

Startup Boston (SB): What was your inspiration to develop Cartwheel Health?

Joanna Shu (JS): I’m a mom of three, and all of my kids have had head lice multiple times. The treatments on the shelf are hard to use, and they contain ingredients I did not want to put on my children.

The first time we dealt with lice was right after my divorce when I was alone with a six-year-old and a one-year-old, and both had lice. I had never dealt with it before, and I had no family nearby to help, so it felt overwhelming. I ended up buying whatever I could find on the shelf.

Years later, after I remarried and we had our youngest daughter, she got lice from my middle son after baseball. The boys and their teammates would throw their hats in the air, pick one up, and put it back on. At the time, it seemed so cute. But a few weeks later, my son said his head was itchy. Not long after that, he was sitting with his baby sister reading a book, with their heads touching. I even have a picture of that heart-warming moment, but I realized later that was probably when she got lice!

When I went to buy another treatment, my husband noticed it was not approved for children under two. Our daughter was one year and 11 months old, and I was ready to use it anyway. He said no, and instead we manually combed through her hair one strand at a time. In that moment, I thought there had to be a better solution.

When I met my co-founder and learned about this technology, I immediately recognized both the problem and the potential solution.

SB: Tell me how that came to be. How did you know this was the right formula for Nit Happens?

JS: When the inventor brought us this technology, it checked every box. He had clinical data showing it was 95.8% effective. If you look at many of the products on the shelf, some are only 30% to 40% effective. If parents knew that, they probably would not buy them. Most brands do not advertise those numbers, but we put our efficacy front and center. On our Walgreens packaging, we have a large gold foil sticker that says greater than 95% efficacy.

He had also completed dermatological testing showing it was non-irritating. It was all natural, with no preservatives. The formula uses an organic coconut oil base along with walnut shell powder, diatomaceous earth, orange extract, and other ingredients I can actually recognize and understand. That gave me real confidence in using it on my own kids.

SB: I noticed you use humor for your brand, which can be rare in branding. What made you decide to go in that direction?

JS: We lean into humor because lice is a yucky subject that creeps people out. Whether I’m writing to supporters and investors or talking to people at a trade show, I know no one is going to engage with dry, clinical messaging about lice. If I send a quarterly update with no personality, people will not read it.

At trade shows, our booth says, “Your kid has lice, that stinks, we’ll fix it naturally.” People often walk by at first and make a face, so I’m like a carnival barker and try to joke with them and say, “Welcome to the lice booth!” Once they laugh, they stop, engage, and start talking. Maybe they say their sister’s kids had lice, or they ask questions for a future situation. Teachers and nurses especially connect with what we are doing.

We take the same approach in our newsletter. We try to make it funny and human. One supporter once replied that he “snorted twice” while reading it, and I thought that was a perfect review.

Lice can feel scary and stressful for parents, so part of our goal is to lower the temperature. We want people to know this is normal. Most families will deal with it at some point, and we are trying to make that experience feel less overwhelming.

SB: This is your second company you started. You also founded Refresh Skin Therapy. Tell me about that experience and how it helped you launch Cartwheel Health. Has your decision-making process changed from then to now? If so, how?

JS: There are a lot of similarities, although we've done everything backwards from Refresh.

With Refresh, we started online through Amazon and direct-to-consumer sales. From there, we expanded to Costco.com, then into Costco, Sam’s Club, and Walmart.

With Cartwheel, we went straight into 6,000 Walgreens stores before we had even made a single sale on our own website. It was a huge retail rollout from the start, and we did that intentionally. This is an urgent purchase. When a parent discovers their child has lice, they want to solve it immediately. Waiting two or three business days is not realistic, and even same-day or next-day shipping may not be fast enough.

That makes it a riskier strategy, no question. But I believe in this product very strongly because of the data and because of what we have learned in this category over the last few years. There is a real need.

We believe the product will do well. The challenge is awareness. When parents are standing in front of the shelf, we want them to choose us because of our packaging, our messaging, and the strength of our claims.

SB: So how do you approach fundraising now compared to before? How are you navigating the expectations and challenges that come with being an experienced founder?

JS: It has been completely new for me. At Refresh, we bootstrapped the business. It was just me and a business partner, and we put in whatever cash we could afford. Then everything the business earned went right back into it for a long time.

I had never raised outside capital before. My co-founder had raised money in the past, and she told me very directly that if I wanted to be paid a salary, we needed to raise money. She said she would show me how. I asked how long she thought it would take, and she said about three months. It ended up taking nine months before we got our first check, and it certainly was not enough to pay a salary. That was a real wake-up call.

I was always a pretty shy person. For me now, it's, “do you want to eat or you want to be shy?” So there’s no more being shy, that's canceled. Now, anytime I have a chance to speak, I take it. Put me in front of investors, moms, buyers, or nurses, and I am ready.

Another big shift has been travel. With Refresh, I did not have to raise money, so I was not on the road very much. With Cartwheel, I travel A LOT. Early on, my husband understood that before I did. He told me that if I wanted this company to succeed, I needed to be out there. I was hesitant because we have three kids, but he kept saying, “This is your time.”

Once we got the Walgreens order, he told me, “You have to do this. I’ve got things covered.” That was incredibly liberating. He has been amazing, handling everything during the week. It took time for the kids, and for me, to adjust. I carried a lot of guilt at first, but now we have found our rhythm.

I really believe that when it comes to raising money, people need to look you in the eye. That personal connection matters.

SB: Switching gears a bit. You were part of the Mass Innovation Network’s 2024 Eddies Program. How did that help Cartwheel Health get its start? 

JS: They gave me access to a network I did not have before. I did not really know people in medical devices or investors in the Northeast, and Mass Innovation Network helped me build that network. It has been incredibly important.

They are also a well-respected organization. This is not some unknown accelerator. Their reputation carries weight, especially in medical devices and technology, and being associated with them opened doors for us.

Being part of the Eddies helped people hear about us for the first time. I remember pitching to an investor group and having a woman come up afterward to say she had first seen me pitch at the Mass Innovation Eddies Finals. That kind of visibility made a real difference.

SB: And one more question. For anyone looking to become a founder, what are some lessons learned you can share? 

JS: Whenever I speak with students, young people, or entrepreneurs, I say, “Do it now!’ 

Don't wait. There is no later. I mean that for a few reasons, but mostly because of family. It's a lot easier to go without a paycheck and couch surf when you're young. The first year and a half when I didn't get a salary was hard with a family of five. 

Do it before you've got family depending on you when you can still fall back on somebody. It's a lot easier to be broke when you're 20 than when you're 40. 

Final thoughts

Joanna Shu’s story is a reminder that successful founders are not defined by having all the answers the first time around, but by what they choose to do with the lessons they earn along the way. With Cartwheel Health, she’s applying experience, resilience, and sharper instincts to solve a real problem in a category many overlook. Her journey also highlights something every aspiring entrepreneur should hear: there is no perfect time to start, only the decision to begin. 

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About the author: Kathleen Ohlson is a Boston-based content writer with a background as a high-tech writer and storyteller. With a passion for creating content that resonates with audiences, you can connect with her on LinkedIn.