Nephrologist, Intensivist, and Longevity Specialist
Dr. Kathleen Léger is a triple board-certified physician in Internal Medicine, Nephrology, and Critical Care Medicine, bringing exceptional clinical rigor to Extension Health’s personalized longevity and performance-focused care.
Her background spans some of the most complex environments in medicine, where she has spent over a decade managing multi-system conditions that demand precision, nuance, and data-driven decision-making. This depth of experience allows her to see patterns across organ systems—and intervene earlier, smarter, and more holistically.
Dr. Léger has a strong clinical focus on women’s health and female hormone optimization, with particular interest in how hormonal shifts influence energy, cognition, metabolic health, cardiovascular risk, and long-term aging trajectories. Her approach integrates evidence-based medicine with emerging insights from functional and preventive care to address root causes rather than isolated symptoms.
She is completing advanced training in Functional Medicine through the American Academy of Anti-Aging Medicine (A4M) and holds a Nutrition Science certification from Stanford University, reinforcing her systems-based, whole-person approach.
In addition to her clinical work, Dr. Léger is an active researcher and educator, with peer-reviewed publications, leadership roles in clinical trials, and experience developing physician training curricula. She is also involved in global health education initiatives.
At Extension Health, Dr. Léger partners closely with patients to translate complex data—labs, biomarkers, imaging, and lifestyle inputs—into clear, actionable strategies that support hormonal balance, resilience, and long-term vitality, particularly for women navigating high-performance lives.
Certifications
MD, Board Certification in Internal Medicine, Nephrology, and Critical Care Medicine.
Languages
English
French
Haitian Creole
Spanish
Education
BA: Binghamton University, State University of New York
MD: Upstate Medical College, State University of New York
Residency: NYU Langone Long Island Hospital
Fellowship: Yale New Haven Hospital
