One physician, every appointment.
The physician who designs your protocol is the physician you'll see at every follow-up.
Jahan Fahimi, MD, MPH
Board-certified in Emergency Medicine. MPH, Harvard School of Public Health. 40+ peer-reviewed publications in preventive medicine and population health.
Dr. Fahimi designed the clinical frameworks underlying every Decades program. His research background in preventive medicine and population health shapes how Decades approaches protocol design — emphasizing evaluation, monitoring, and outcomes over speed and volume. He serves as Clinical Director, overseeing the evidence base behind each treatment program.
Jason Valadao, MD
Board-certified in Family & Sports Medicine.
Dr. Valadao brings a performance medicine background to hormone optimization and longevity care. His training in Family & Sports Medicine gives him a comprehensive view of the body — not just hormone levels in isolation, but how testosterone interacts with training load, recovery, sleep, and metabolic health. He works with both men and women across the Decades programs, with particular depth in hormone optimization, performance medicine, and preventive care.
Daniel Singer, MD
Board-certified in Emergency Medicine.
Dr. Singer specializes in metabolic health and body composition. He uses continuous glucose monitoring (CGM), DEXA body composition analysis, and comprehensive metabolic panels to build and adjust protocols over time. His focus on what the data actually shows — rather than what a patient or physician might assume — makes him particularly well-suited for GLP-1 and metabolic programs. He works with both men and women across metabolic health, cardiovascular risk, body composition, and performance — bringing data from CGM, DEXA, VO₂ max, and sleep analysis to bear on each patient's plan.
Raveena Rihal, MD
Board-certified in Internal Medicine.
Dr. Rihal focuses on women's health across the full picture — hormonal health, perimenopause and menopause, metabolic care, and weight management. Her internal medicine training means she evaluates all of these together rather than in isolation, and stays with each patient through every appointment for the duration of their program. Currently seeing patients in California.
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