Functional medicine, which focuses on identifying and treating the root causes of chronic illness, is catching on with payers. Healthcare Innovation recently spoke with Robin Berzin, M.D., CEO and founder of Parsley Health, which now has arrangements with many major plans – including Aetna, Cigna, UnitedHealthcare, BlueCross BlueShield, Humana, and Centene

Parsley Health says these payers covering services such as provider visits, diagnostic testing, and clinician-directed prescriptions for its patients marks a shift for a category of care that has historically been expensive, fragmented, and out of reach for most patients. 

Healthcare Innovation: Could you start by describing what distinguishes functional medicine from traditional care?

Berzin: Health optimization and treating the root cause of disease are the two pillars of functional medicine. We both identify the root cause drivers of today's diseases and symptoms and conditions and seek to treat them in a way that's more effective and sustainable. In the process, we help optimize health. To give you an example, I had a patient who was on $800 worth of asthma drugs a month, yet still going into the hospital twice a year for asthma exacerbations. By identifying that she was actually allergic to wheat and dairy and getting her off of those foods, we were able to put her asthma into remission and get her off all drugs. We have helped so many people put inflammatory diseases like asthma into remission.

HCI: A press release about Parsley Health quotes you as saying functional medicine was once a luxury item — expensive, hard to find, and of inconsistent quality, but that Parsley has solved all those problems. How has it solved them?

Berzin: Functional medicine was all those things — very expensive, hard to find a doctor, and really inconsistent across the field. I realized that none of that was going to make us able to work with the existing healthcare system or make this accessible to the people who need it most. 

So how did we fix those things? No. 1, when we started the company, we standardized the care. We built our own fellowship to train providers. We built an evidence-based set of functional medicine protocols that all had data behind them. We trained all of our providers in those protocols so that we had a standardized, systematized way of practicing evidence-based functional medicine. We also built our own tools, like the Parsley Symptom Index, which we've published in peer-reviewed literature, that gave us a way to track whole body symptoms across nine body domains over time in a validated way. So we really standardize the care model. 

No. 2, we went national via telehealth. You can access Parsley Health in all 50 state via telehealth. Functional medicine really lends itself beautifully to prescribing medications and ordering lab tests via telehealth and working with people over a video consult, so that means you don't need to live near a functional medicine doctor's office, which were few and far between. That was a way that we expanded access and created consistent quality. 

The third thing we've done has been to bring us in-network with payers. This has been a real journey. We started off as a cash pay model, because my view at the time was: build the care model, get it right, and don't be constrained by what insurance pays for today, because insurance pays for an episodic, reactive, transactional form of care. So if we just go from day one into what it pays for, we'll end up operationalizing everything toward that and not getting this right. We needed to innovate something different. 

But my vision was always that we would be in-network. We quietly started building toward that goal. We launched with our first health plan, which was Aetna, in New York in 2023. We have validated health outcomes data. It took a lot of work to just get that first individual, little local contract. We then expanded in New York, in partnership with Mount Sinai Hospital, and then expanded to a couple of plans on the West Coast, and now have expanded nationally. For me personally, it's a huge milestone to bring functional medicine to 150 million lives on major health plans.

HCI: Is the model that patients buy a membership but now their insurers can be billed for labs, etc.?

Berzin: There's an annual program fee [typically $1,500 annually] to help pay for the things we can't bill for but that are part of the program. The in-network billing covers your medical visits, so when you see the doctor, we bill your insurance. We can also bill your prescription drugs and lab tests, as an in-network provider.

In addition, however, Parsley does a lot in our care model to ensure the level of service and care team support and connectivity with us that doesn't happen in a typical primary care setting. You don't just get a doctor — you get a care team that includes a nurse, a functional medicine nutritionist and dietician, a care coordinator and a member experience leader, who all are assigned to you. It's what's called a dedicated care team model. You're working with this whole team, because what we learned is that in order to actually get people better, we can't just see you a couple of times a year and then wonder what happens to you in between. We work with you as a care team. We also have a digital platform that enables you to message us and work with us asynchronously. This approach helps us drive the kind of outcomes and patient experience that we want.

HCI: Do you think that being in network with all these payers will bring functional medicine to a much wider patient population?

Berzin: Absolutely. It's going from a little under 15 million covered lives, which is where we were before, to 150 million covered lives. We do have a cash pay price, and this cuts that price by nearly 60%, and that price drop is about making it more accessible. I think people understand with the program fee that this medicine is different; it is not your standard primary care visit. We are spending more time with you. We are diving into your health. We have additional training. You're working with a team.