About
Dr. Ian Kroes grew up in Lafayette in the East Bay, shaped early by his father's example. Dr. John Kroes spent decades making house calls, attending births and deaths, and building deep bonds with the families he served. D. S. in Applied Physics and Biology at UC Berkeley.
Before founding Peninsula Doctor, Dr. Kroes spent over a decade at the Palo Alto Medical Foundation Clinic. There he cared for as many as three generations of the same families simultaneously. He now brings nearly two decades of family medicine experience to his Menlo Park practice. He holds membership in the American Academy of Family Physicians and the American Society for Nutrition. He also lectures at Stanford University School of Medicine. His clinical interests span preventive care, cholesterol management, hypertension, diabetes, hormone replacement therapy, nutrition, fitness, and brain health. Patients describe him as an old-fashioned kind of doctor who treats them like a trusted friend.
Education & Training
Undergraduate
B.S. Applied Physics (Biology), University of California, Berkeley
Medical School
M.D., Stanford University
Certifications
Conditions Treated
Who is Dr. Kroes right for?
Dr. Kroes is a strong fit for adults and families who want a long-term primary care relationship. Patients managing chronic conditions like diabetes, hypertension, or high cholesterol benefit from his preventive focus. Those interested in nutrition, fitness, or hormone health find his dual expertise in medicine and nutrition valuable. Patients who value a doctor who knows their full history, not just their chart, tend to thrive in his care.
Similar Doctors Nearby
Dr. Jessica LevatinoMD
chronic illness, diabetes, hypertension +8 more
Dr. Judy KimM.D.
menopause, perimenopause, women's health conditions +4 more
Dr. David HiroshimaM.D.
asthma, allergies, hormonal imbalances +3 more
Frequently Asked Questions
Dr. Kroes treats a broad range of conditions including hypertension, high cholesterol, diabetes, and hormonal imbalances. He also focuses on preventive care, brain health, and nutrition-related conditions. His background in applied biology and membership in the American Society for Nutrition inform his approach to metabolic and lifestyle health.
D. from Stanford University. He brings nearly two decades of family medicine experience to his practice in Menlo Park.
Dr. Kroes earned his undergraduate degree in Applied Physics and Biology from UC Berkeley, then completed his medical degree at Stanford University. Before founding Peninsula Doctor, he spent over a decade practicing at the Palo Alto Medical Foundation Clinic.
Yes, hormone replacement therapy is a clinical focus for Dr. Kroes. He treats both men and women dealing with hormonal changes, including testosterone therapy and menopause-related care.
Dr. Kroes takes a proactive approach to health, emphasizing early detection and lifestyle management. He incorporates nutrition counseling, fitness assessment, and advanced diagnostics into his preventive care work. His membership in the American Society for Nutrition reflects his commitment to evidence-based nutritional medicine.
Yes, Dr. Kroes has a long history of caring for multiple generations of the same households. At the Palo Alto Medical Foundation Clinic, he treated up to three generations of the same families simultaneously. He continues that tradition at Peninsula Doctor.
Yes, Dr. Kroes lectures at Stanford University School of Medicine. His academic involvement keeps him engaged with current research and clinical developments in family medicine and preventive care.
Dr. Kroes grew up watching his father, Dr. John Kroes, make house calls and build deep relationships with the families he served. That example shaped his belief that the best medicine comes from truly knowing your patients over time.
Doctor profile last updated March 21, 2026