Dermatologists prescribe more oral antibiotics per clinician than any other medical specialty. Between 2008 and 2016, nearly 12,000 unique dermatologists prescribed 985,866 courses of antibiotics, with doxycycline hyclate, minocycline, and cephalexin being the most commonly prescribed. Many of these prescriptions are written for chronic inflammatory conditions like acne, rosacea, and eczema, with treatment courses often extending for months or even years.
While overall antibiotic prescribing by dermatologists decreased 36.6% between 2008 and 2016, a concerning trend emerged: antibiotic use following dermatologic surgery increased dramatically by 69.6%. Meanwhile, dermatologists often prescribe medications like doxycycline for acne for months and sometimes for years, in contrast to the typical three to fourteen day courses prescribed by most other clinicians.
The consequences of prolonged antibiotic use are becoming increasingly clear. Resistance rates for C. acnes, the bacterium associated with acne, have reached concerning levels, with some studies showing resistance to commonly prescribed antibiotics. Meanwhile, patients cycle through years of trial-and-error treatments, often without understanding why something works for one person but not another.
Natalise Robinson, co-founder and CEO of Parallel Health, has a different vision for how dermatology should work. Her company combines microbiome testing with phage therapy to deliver personalized skin treatments matched to each individual's unique bacterial composition. In this episode of Growth Layer, Robinson shares how personal experience with autoimmune diseases led her to build a health tech company at the intersection of microbiome science, precision medicine, and telehealth.
From Autoimmune Disease to Microbiome Science
Robinson's path to founding Parallel Health began with observation rather than inspiration. Growing up with family members who had autoimmune diseases, she noticed a puzzling pattern: the people she knew dealing with these conditions were often on antibiotics.
"If you're on antibiotics for an autoimmune disease, you're like, well, what's actually happening there for you to get relief from antibiotics?" Robinson explains. "So there's obviously a connection between the microbiome or some microbial dysbiosis and autoimmune disease."
That seed of curiosity led Robinson to pursue a career in health, jumping from startup to startup in pet health and mental health before landing at a company where she met her co-founder, Dr. Nathan Brown. Brown, a microbiologist with a PhD background, was working on something Robinson had never heard of: phage therapy.
Phages are natural microbes that attack bacteria with remarkable precision. They exist everywhere in nature, including millions living on and in your body right now. Their job is singular: control bacterial populations so they don't overgrow. Brown had completed his postdoctoral work in the UK under the Gates Foundation and Wellcome Trust, building phages for shigella.
At their previous company, Brown was tasked with creating the first phage serum for acne, targeting C. acnes, the bacterium most studied in relation to acne. The company sold this acne phage serum to consumers at large. The results revealed something important.
"It worked really well for some people," Robinson recalls. "Didn't, was very neutral, or didn't work at all for other people. And we said, well, why? How is there such a huge discrepancy? Well, it turns out everyone's different."
The people with C. acnes overgrowth saw dramatic results because the phage was perfectly matched to their condition. But other people who said they had acne actually had fungal issues or different types of bacteria. They needed a different phage entirely. The light bulb moment was obvious in retrospect: test people's microbiomes first, then give them the right phage.
Building a Company Around Personalization
Robinson and Brown brought this idea to their employer. The response was no. It was a biotech play, too expensive, not the direction they wanted to go.
Brown left the company and called Robinson a few months later. "I'm having a lot of conviction around this idea," he told her. "I want to do this, and I would love for you to do this with me as the CEO."
Robinson's response: "I don't know, of course."
The uncertainty was understandable. What they were proposing had never been done before. They would need to collect massive amounts of data to match people with the right phage. They would need to build technology from scratch. It was a significant technical and operational challenge.
They decided to apply to the Y Combinator accelerator as a way to test the idea's viability. Robinson made a deal with herself: if they got in, she would quit her job and commit fully. If not, back to the drawing board.
They got in.
Even then, Robinson hesitated. She went back to one of her professors at the Graduate School of Business with her doubts. "I don't know if I should do this. It's a lot. I don't know if I'm cut out to be a CEO."
The professor's response was simple: "If not you, who? If not now, when?"
Looking back, Robinson appreciates the directness. "I think a lot of times we can overthink things, analyze ourselves out of anything."
The Identity Leaps of Scaling
Parallel Health was started in 2021 but didn't truly launch until 2024. The company is now in its fourth year, though many people assume it's been around longer, a testament to the presence the company has built.
Robinson reflects on the psychological dimension of being a founder. "There are these identity leaps and shifts that one has to make," she notes. "When you take a startup from zero to a million, from a million to five to ten, you have to evolve along the way."
Everyone develops their own tools for navigating these transitions. Robinson mentions exchanging recommendations for astrologers and intuitives with a longtime founder her team works with. "That's part of our walk, right? You kind of have to figure out your support system to move you along the way."
What Parallel Health Actually Does
Acne affects up to 50 million Americans annually, making it the most common skin condition in the United States. Globally, acne vulgaris affects an estimated 9.4% of the population, making it the eighth most prevalent disease worldwide. Studies show that approximately 85% of people between ages 12 and 24 experience at least minor acne, with prevalence rates among adolescents ranging from 35% to over 90%.
The condition doesn't end with adolescence. Adult acne affects 15-20% of women, often associated with hormonal fluctuations and stress, with about 50% of women in their twenties continuing to experience acne. But acne is just one of many inflammatory skin conditions that Parallel Health addresses through microbiome science.
Parallel Health is a fully licensed telehealth practice that marries microbiome science with traditional dermatology. The company isn't suggesting that dermatology should be thrown out. Instead, they're adding another tool: a skin discovery test using whole genome sequencing.
"Let's understand what your microbiome looks like," Robinson explains. "Let's create a regimen that's unique to you that's going to work for you."
For some people, phages do the trick completely. For others with severe chronic issues, the solution might be multifactorial. It might involve both microbial dysbiosis and hormonal factors. Parallel Health aims to identify all root causes and address them simultaneously.
The conditions the company treats include acne, eczema, rosacea, and even pigmentation issues now being linked to microbiome dysbiosis. The company also addresses aging. Even people with great skin can experience low-grade chronic inflammation as they get older, and any chronic inflammation accelerates aging. Parallel Health looks at both prevention and deceleration of skin aging.
Three Distinct Customer Segments
Parallel Health's first customers fell into two buckets, Robinson explains, with a third segment emerging over time.
The first group consists of people with chronic conditions who don't want to use antibiotics, or for whom antibiotics simply don't work anymore or never have.
The second group Robinson calls "the biohackers of skin." These customers want anti-aging benefits. They want their Botox to last longer. They want to do everything possible to improve their skin and support skin longevity.
The third segment that emerged: parents who don't want their kids on Accutane or antibiotics.
"That's been one of the challenges as a business," Robinson acknowledges, "because investors are telling us, well, why don't you focus on one? And we're like, no, we don't want to. We want to focus on anyone who needs this."
The Go-to-Market Challenge
With distinct customer segments and a novel technology that requires education, Parallel Health's go-to-market strategy has been shaped by resource constraints and the nature of what they're offering.
"We honestly have not, we just haven't paid for marketing," Robinson says. "As a startup, we've done experiments here and there, but we're not that company that you see a million ads from.
"Part of this is resource allocation. Much of Parallel Health's budget goes to research and development, to the science itself. But part of it is also the educational challenge. "Because we're doing something new, there's a huge educational component, right? It's not like I can just put up an ad and say, 'Hey, there's phage therapy.' That doesn't work.
"Instead, the company has relied on word of mouth, earned media, press coverage, and community events where they can actually talk to people and share the science. "When we can share what the science is behind what we do, people are like, 'Oh cool, that's awesome,'" Robinson notes. "But it does take more than three seconds to share what this is really about."
Parallel Health also works with dermatologists and functional medicine doctors, offering their skin test as a tool for clinicians. With quantitative whole genome sequencing and personalized phage therapy, Parallel provides capabilities that most dermatologists don't have access to.
The company started purely direct-to-consumer but only began working with clinical partners about two quarters ago. The split is currently more weighted toward direct-to-consumer, but the B2B channel is growing quickly.
The Evolution of the Product
When Robinson and Brown first pitched to investors and Y Combinator, their line was: "We want to build an end-to-end health platform where we test and then we provide a solution."
That vision hasn't changed, but the execution has evolved significantly. The company initially launched with a face test and phage serums for facial application. Then something interesting happened.
"As people started testing, they're like, 'Hey, can I test my XYZ?'" Robinson recalls. People wanted to know about their scalp, their body, a weird issue on their elbow.
The team realized they had the technology to test anything. They just hadn't marketed it that way. At the end of last year, Parallel officially launched a scalp health test, a body odor test, and a body blemish test. Now the company will create custom kits for people who want to test multiple areas not listed on the website.
What makes Parallel's testing unique goes beyond the sequencing technology. Every test includes a control sample where customers hold a swab in the air, essentially testing their environment.
"That has actually been really interesting in certain cases," Robinson explains, "because it has been revealing when there are really high microbial counts in the air and we know what they are."
Because Parallel has comparative data on what a normal room should look like, they can flag when something is off. "We can tell patients or customers, 'Hey, your room has a lot more microbes than the average, so what is going on here?'" This has helped troubleshoot environmental factors, lifestyle patterns, and other contributors to people's microbiome health.
Building a Proprietary Dataset
Behind Parallel Health's personalized recommendations sits something more valuable than any single product: a massive, proprietary dataset of microbiome information.
The company had to start with a substantial dataset to make their matching algorithms work. As they've grown, they've continued learning about what microbiomes look like across different ages, ethnicities, skin issues, and geographies. Parallel ships internationally, so they're seeing how microbiomes differ across populations.
The company also offers free testing every six months for customers on their MD-3 protocol plan. This isn't just a customer benefit. It's a data strategy. "We want to monitor because we know that your microbiome evolves over time with age," Robinson explains. "We're collecting this longitudinal data. We're seeing patterns."
Parallel was using machine learning before the current AI revolution. Now they use AI tools as well, but they've had to create unique bio-algorithms to understand what they're seeing in the data.
"What that means for the future of Parallel is that we really believe that we're building a predictive health engine," Robinson says. The vision: look at someone's microbiome today and not only see current dysbiosis but potentially predict issues they don't have yet based on certain overgrowths. "That becomes really interesting when you think about more severe diseases," Robinson notes. She's quick to add that acne can be very severe, but the implications extend to skin cancer, variations of psoriasis, autoimmune disease, and more.
The timeline for this predictive capability? "Maybe something in the next year or two," Robinson estimates. AI's rapid evolution is accelerating their analysis, and they're focused on treating current patients while continuing development work in the background.
Customer Results and Retention
Early-stage companies often struggle to keep customers engaged, but Parallel Health has seen strong retention. Some customers who started with the company early on are still with them today.
"Certainly, I would say people stick with us for at least five or six months," Robinson notes. "But some people are with us for well over a year."
Results vary by individual, as you would expect from personalized medicine. Some people report reduced inflammation and redness within 24 to 36 hours. Robinson herself uses her custom phage as a spot treatment. "When I know that something's coming on, I'll use it. It'll go away within 24 hours."
For people with more chronic, severe issues, clearing can take longer: three months, six months, sometimes nine months. The timeline depends on the complexity of the condition and what root causes are being addressed.
The Bigger Picture: Rethinking One-Size-Fits-All
Working at Parallel Health has fundamentally changed how Robinson thinks about health and wellness products.
"Your microbiome is as unique as your fingerprint," Robinson emphasizes. "When you think about products that you use, it just makes me realize that this one-size-fits-all kind of landscape that we've had for decades, it's like we can do better. At this point, we should."
The implications extend beyond skincare. Ninety-nine percent of the DNA in and on our bodies isn't even human. It's microbial. "We have to learn to work with our microbes, not against them," Robinson says. "When we're taking antibiotics, we're carpet bombing our microbiomes. We really need to work with our systems."
This raises interesting questions about other approaches to microbiome health, like probiotic supplements. Robinson acknowledges it's a big question. "I certainly think personalized probiotics will be the future because there are bacteria that are good for everyone. But again, everyone's different. It might help others more than it could help you. You don't really know until you understand what you're working with."
Lessons for Health Tech Founders
Several themes emerge from Parallel Health's journey that apply broadly to founders building in precision health and wellness:
The education burden is real. Being first in a category means carrying the full weight of consumer education. This requires different channels and longer conversion funnels than established product categories.
Resource allocation determines strategy. Parallel's focus on R&D over paid marketing wasn't just a philosophical choice. It reflected where they needed to invest to build differentiated technology. Understanding your core advantage shapes where you can and can't compete.
Customer segmentation can be a feature, not a bug. Investors often push for focus, but serving multiple segments with a single platform can be a strength if the underlying technology and value proposition are broad enough.
Data is the moat. In precision health, the proprietary dataset you build through serving customers becomes your most defensible asset. Each customer interaction improves the platform for everyone.
Partnership channels take time. Parallel launched in 2021 but only started working with clinical partners in late 2024. The B2B healthcare channel requires credibility and clinical validation that early-stage companies build over time.
Founder psychology matters. Robinson's candor about identity leaps, support systems, and the tendency to overthink decisions reflects a reality many founders face but few discuss openly.
The Path Forward
Parallel Health represents a shift in how we think about dermatology and skin health. Rather than carpet bombing with antibiotics or applying the same treatment to everyone with a given diagnosis, the company is building toward truly personalized medicine based on individual microbiome composition.
The predictive health engine Robinson describes would represent another leap forward: moving from reactive treatment to anticipatory care. If patterns in today's microbiome can predict tomorrow's conditions, the potential applications extend far beyond current skin health applications.
Research shows that phage therapy may represent a microbiome-sparing approach to treating bacterial infections, selectively targeting pathogens while preserving beneficial bacteria. Recent studies highlight phage therapy's potential across multiple dermatological conditions including acne, psoriasis, and atopic dermatitis, though larger clinical trials are still needed to establish widespread clinical protocols.
For consumers, the message is straightforward: what works for someone else's skin might not work for yours because your microbiome is as unique as your fingerprint. The future belongs to companies that can match treatments to biology rather than prescribing based on averages.
Finding Parallel Health
Parallel Health currently serves customers throughout the United States and ships internationally. The company offers various testing options including facial skin tests, scalp health tests, body odor tests, and body blemish tests, as well as custom testing kits for multiple areas.
Customers can access Parallel Health's services directly through their website or through partnerships with dermatologists and functional medicine doctors who offer the testing as part of their practice.
For customers on the MD-3 protocol plan, the company provides free testing every six months to monitor changes and adjust treatments as the microbiome evolves.
The Growth Layer is a conversation series from Future Digital exploring how real growth happens in health, wellness, and family brands. Each episode examines the decisions, pivots, and behind-the-scenes work that shapes category-defining companies. Subscribe for more founder stories and insights from leaders transforming care through precision, personalization, and patient-centered innovation.
