According to Oxford Languages, functional medicine is defined as a medical practice or treatments that focus on optimal functioning of the body and its organs, usually involving systems of holistic or alternative medicine. The Institute for Functional Medicine (IFM) notes that it “determines how and why illness occurs and restores health by addressing the root causes of disease for each individual.” Related terms that encompass aspects of functional medicine include integrative, mind-body, holistic, lifestyle, complementary and naturopathic medicine.

As defined by Oxford Languages, integrative medicine is a form of medical therapy that combines practices and treatments from alternative medicine (e.g., Chinese herbal therapy, holistic psychotherapy, Reiki energy healing) with conventional medicine. According to Andrew Weil, MD, considered by many to be the founder of American integrative medicine, it is a healing-oriented medicine that takes the whole person into account, including all aspects of lifestyle. Integrative medicine emphasizes the therapeutic relationship between practitioner and patient, is informed by evidence and makes use of all appropriate therapies. Functional medicine can be viewed as a practice type within the broader integrative medicine category.

Functional medicine does not typically diagnose diseases but instead identifies underlying factors and “clinical imbalances” that contribute to disease. Common findings of functional medicine include nutritional deficiencies, food allergies, hormone imbalances and leaky gut. These conditions are not accepted by traditional medicine as underlying causes of diagnosable conditions such as diabetes or depression. Furthermore, the laboratories, lab tests or lab results from functional medicine providers may not be recognized by traditional clinicians. Particularly with respect to functional medicine, differences in philosophy and methods create potential challenges for patients attempting to reconcile discrepancies in diagnoses and treatment recommendations. Additionally, people with symptoms that have not been diagnosed or fully addressed by traditional medicine often find the greatest benefit from functional and integrative medicine.

The most prominent certification is offered by IFM through its Functional Medicine Certification Program. This program helps established practitioners “develop advanced skills and competence in the treatment of patients but does not grant any additional legal or specialty status.” Licensed providers with verified credentials are eligible to apply for certification training: physicians (MD or DO); chiropractors (DC); naturopathic doctors (ND); dentists; nurses, nurse practitioners and physician assistants; pharmacists; physical and occupational therapists; registered dieticians and certified nutrition specialists; and mental health professionals. The University of Arizona Center for Integrative Medicine was created in 1994 to advance research and training for integrative health practitioners and, along with Duke University and the University of Massachusetts, co-founded the Academic Consortium for Integrative Medicine and Health. Many participating academic centers offer fellowship training for physicians in conjunction with the American Board of Integrative Medicine.

The Academic Consortium for Integrative Medicine and Health has over 70 member institutions in the U.S. and is growing. Yale School of Medicine, Stanford Medicine, Duke Integrative Medicine and Northwestern Medicine are among its members, as is Cleveland Clinic, whose Center for Functional Medicine is affiliated with Mark Hyman, MD, Board Chair of IFM and well-known author, podcast host and media commentator. Functional medicine is also widely available through small independent practices and by telemedicine. Parsley Health, a largely digital provider, offers individual memberships for virtual care in 44 states.

Programs increasingly coexist within academic medical centers and health systems, although sometimes uneasily; functional medicine’s clinical model is not well understood or fully acknowledged as meeting accepted standards of care by many physicians in traditional practice. While health systems continue to add functional medicine services they may be siloed, in which case patients may find their treatment team is not fully collaborative.

Hospital-affiliated centers of functional and integrative medicine may look very different from one another. Lifestyle habits are the core of most integrative and functional medicine programs: nutrition, sleep, exercise and stress management. Lab tests followed by recommended nutritional supplements are common practice; firstline therapies are typically dietary changes along with herbal, vitamin and mineral supplements. Complementary therapies such as massage, acupuncture, “energy healing,” Chinese herbal medicine and many others may be available. Areas of focus may include chronic pain, metabolic disease, cancer, aging, heart disease, mental health conditions, women’s health and pediatrics, among others.

In the current state, employees and companies can expect to pay for most or all functional medicine services separately as they often are not covered by insurance. Certain services may be HSA/FSA qualified expenses and post-tax Lifestyle Spending Accounts may be another payment option, if offered. Employers may consider offering well-being programs that address holistic health and incorporate aspects of functional medicine such as food as medicine, mindfulness and sleep.

Functional medicine does not currently have a strong evidence base in mainstream scientific literature, where a double-blinded randomized clinical trial remains the gold standard. Some integrative medicine practices such as acupuncture can meet this standard, perhaps due to a longer history alongside traditional medicine and a presence outside the US. Advocates for functional medicine claim a science base and in fact there is accepted evidence for many functional medicine principles such as the role of inflammation in ill health, the gut microbiome as key to immunity and the gut-brain connection as central to mental health; basic science research in these areas is proceeding apace. While physicians in traditional medicine are neither focused on or trained to address these issues, functional medicine is seeking to do so.

Functional and integrative medicine and related alternative services are resonating strongly as consumers increasingly desire health care with a whole person well-being focus. Functional and integrative practices offer the promise of human-centered holistic care that is the opposite of what Dr. Mark Hyman, a leader of the functional medicine movement, calls the “name it, blame it and tame it” pattern of traditional medicine in which “payers pay to treat disease and doctors don’t know how to create health, perpetuating a model of care that costs trillions and doesn’t get results.” Functional medicine instead focuses on bodily health (vs. identifying a disease), creating conditions for health and eliminating impediments so the body will activate its own healing systems. In addition, providers typically spend more time with patients, use a team-based and multidisciplinary care model, focus on chronic conditions and are likely to suggest new or alternative treatment approaches. All of this holds appeal for those frustrated by a fragmented, often unfriendly and bureaucratic U.S. health care delivery system with a shortage of primary care providers. Currently, functional medicine is available only to those willing and able to self-fund care. As a result, employers and their insurance partners may see increasing pressure to cover and pay for services.