Dr. Jay Luthar, MD, DipABLM, and Dr. Julia Loewenthal, MD have been named 2026 Castle Connolly Top Doctors, marking the second year they have received this prestigious designation. Only 7 percent of the nation's licensed physicians are chosen annually as Castle Connolly Top Doctors for their specialties in their regions. Both physicians practice at Lutanen Health, a bespoke primary care and longevity practice in Boston's Back Bay, where each doctor cares for no more than 150 patients, a model that prioritizes deep, sustained relationships over volume.
Lutanen Health is the only academically affiliated primary care practice in Boston integrating longevity science into everyday care. Dr. Luthar emphasized the significance of the recognition: “The Castle Connolly recognition affirms what I believe matters most in medicine: time, trust, and partnership. Dr. Loewenthal and I share the conviction that care should be uniquely designed for each individual patient. When you understand someone's biology, context, and goals over time, you can offer care that is not only more effective but deeply human.”
At Lutanen Health, primary care evolves into private health management, identifying risks early and allocating interventions across a lifespan to preserve vigor and delay decline. Both physicians are fellowship-trained in integrative medicine, bringing mind-body science and holistic approaches to lifestyle optimization. Their newly designed 3,000-square-foot healing space in Back Bay includes a state-of-the-art human performance laboratory.
The practice focuses on metabolic health, cardiovascular risk reduction, cognitive preservation, and healthy aging, while managing complex internal medicine cases and addressing older patients' unique needs, such as frailty risk and medication optimization. Advanced diagnostic technologies include AI-guided plaque detection, multi-cancer early detection blood testing, VO₂ max testing, biological age tracking, and genetic analysis. Practice amenities reflect its relationship-driven model, with extended visits, same-day appointments, 24/7 physician access, and complimentary valet parking.
Dr. Luthar completed his residency at Cambridge Hospital, a Harvard Internal Medicine Residency Site, and is board-certified in Internal Medicine, Integrative Medicine, and Lifestyle Medicine. Dr. Loewenthal completed her residency at Brigham and Women's Hospital and a geriatrics fellowship through the Harvard Multi-Campus Geriatrics Program. Both hold academic appointments at Harvard Medical School, bridging clinical care, education, and research to advance healthy aging.
Castle Connolly Top Doctors are nominated by peers and selected by a physician-led research team. Honorees are chosen based on medical education, training, hospital appointments, and disciplinary histories. Doctors cannot pay to be selected. For more information, visit Castle Connolly's Top Doctors list at castleconnolly.com.
