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‍ ‍SUBSTACK: CASE REVIEWS & PRECISION INSIGHTS

Research Publications, 2026:

“Effects of tirzepatide therapy on body weight and body composition in adults with overweight and obesity.”

Dr. Catherine Johnson, M.D.

Dr. Catherine Johnson founded the practice of Precision Medical Care in 2018. She is an Obesity and Emergency Medicine Board Certified Physician and Menopause Society Certified Physician with over 25 years of clinical experience. After years on the front lines in emergency departments teaching medical students and residents, she realized her true calling: building deep, personalized relationships with her patients—learning not just about their symptoms, but their stories, lifestyles, goals, and challenges. 

A proud daughter of Greek immigrants, Dr. Johnson’s passion for health was shaped by the early loss of her father, a PhD chemist, and the vitality of her mother, a retired biochemist and published poet who loves to review medical research with her. This personal and professional background fuels her mission to help others prevent illness, optimize health, and age with strength, integrity and clarity. Upon her graduation from Loyola University Stritch School of Medicine in 2000, she completed her emergency medicine residency training and served as Chief Resident at the University of Chicago.  She has over eighteen years of experience in academic emergency medicine as Assistant Professor of Medicine at the University of Chicago and Assistant Professor of Surgery at Loyola University Chicago. 

Her pivot into longevity and precision medicine began with her personal struggles related to infertility, endometriosis, congenital hip dysplasia, overweight/obesity, prediabetes, insulin resistance, anxiety and perimenopause/menopause. These challenges led her to the research that uncovered life-changing insights about aging, inflammation, and metabolic health. Dr Johnson’s pursuit of healthy longevity is inspired by the work of Dr Eric Topol, Dr Vonda Wright, Dr Eric Verdin, Dr Sara Gottfried, Dr Valter Longo, Dr Nir Barzilai, Dr Florence Comite, Dr Dale Bredesen, Dr Lisa Mosconi, Dr Pauline Maki, Dr Rebecca Thurston, Dr Peter Attia and the many inspiring physicians and scientists who actively contribute to the research and clinical trials related to geroscience and the pursuit of healthy longevity.

Dr. Johnson has achieved advanced certifications from the Age Management Medicine Group and the Institute for Functional Medicine, complemented by advanced fellowship training in Precision Medicine and the Clinical Peptide Society.

At her core, Dr. Johnson is a problem-solver. Her expertise in emergency medicine gives her a decisive edge in quickly connecting the dots and managing complex conditions. She brings a unique, integrative approach to precision and longevity medicine. She specializes in hormone optimization, metabolic health, and evidence-informed lifestyle interventions, helping men and women optimize their healthspan with vitality and resilience.  Dr. Johnson is dedicated to guiding her patients toward renewed energy, purpose, and well-being, one precision-tailored plan at a time.

Dr Johnson is a person of great faith, purpose and love for community and family. Her work is most inspired by her commitment to her husband of over 25 years and their son and daughter who are now college students. She believes community, purpose, and curiosity are essential ingredients to longevity—and she’s here to help you match your wisdom and resilience with a body that is biologically adapted to optimal health.