Summary

Dr. William Bayer is an endocrinologist specializing in diabetes and metabolism with four decades of clinical experience. He earned his medical degree from Loyola University Stritch School of Medicine and completed both his residency and fellowship at Loyola University Medical Center, finishing his fellowship training in 1991. Dr. Bayer speaks both English and Spanish, helping him connect with a diverse patient population.

Dr. Bayer practices at Northwestern Medicine Regional Medical Group in Bloomingdale, Illinois, and maintains hospital privileges at Northwestern Medicine Central Dupage Hospital. He focuses on treating various forms of diabetes, including geriatric diabetes and type 2 diabetes. His expertise includes performing thyroid function tests and complete blood count evaluations to help diagnose and monitor endocrine conditions. Patients have given Dr. Bayer an average rating of 4.0 stars for his care.

Overview based on verified provider data

Quick Facts

  • accepting new patients
  • 4
  • 40 years of experience
  • 26 insurance plans accepted
  • speaks English, Spanish
  • Loyola University Medical Center
  • 9 written reviews
  • 2 specialties
  • 16 areas of expertise
  • 1 hospital affiliation
  • 1 office location
  • Male

Patients’ Perspective

  • Gave an accurate diagnosis
  • Had a good bedside manner
  • Spent time with me

Office Location

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William C. Bayer, MD
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William C. Bayer, MDDr. Melissa McGee, DNPDr. Safa HammamiDr. Oluwatomi Oluwagbemisola Asemota
Endocrinology, Diabetes & MetabolismEndocrinology, Diabetes & MetabolismEndocrinology, Diabetes & MetabolismEndocrinology, Diabetes & Metabolism
Accepts New Patients Accepts New Patients Accepts New Patients Accepts New Patients
40 Years of Experience 11 Years of Experience 12 Years of Experience
No Virtual Visit Option No Virtual Visit Option Virtual Visit Available Virtual Visit Available
Speaks English, Spanish Speaks English, Spanish Speaks English
Bloomingdale , ILHighwood , ILChicago , ILChicago , IL
Med School: Loyola University Stritch School of Medicine Med School: Jordan University Of Science And Technology Faculty Of Medicine Med School: University Of Ibadan College Of Medicine
Current Profile
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Insurance Plans Accepted by William C. Bayer

  • Aetna
  • Aetna - Medicare
  • Aetna Better Health - Medicaid (Managed)
  • Ambetter
  • AmeriGroup
  • Blue Cross Blue Shield
  • Blue Cross Blue Shield - PPO
  • Blue Cross Blue Shield of Illinois
  • Cigna
  • Health Alliance
  • Humana
  • Medicaid - Medicaid
  • Medicaid - Medicaid (Managed)
  • Medicare
  • Medicare - Medicaid
  • Medicare - Medicare
  • Meridian Health Plan - Medicaid (Managed)
  • Meritain Health
  • Molina Healthcare - Medicaid (Managed)
  • Nippon Life Benefits
  • North Shore LIJ CareConnect
  • North Shore LIJ CareConnect - IPA
  • Priority Health
  • Tricare
  • UnitedHealthcare
  • UnitedHealthcare - Medicare

Medical Specialties

William C. Bayer has the following 2 specialties

Specialty Expertise

William C. Bayer has the following 16 areas of expertise

  • Acromegaly
  • Addison Disease
  • Cushing Disease
  • Diabetes
  • Diabetes Mellitus, Type 1
  • Diabetes, Type 2
  • Endocrinology
  • Endocrinology & Metabolism
  • Fatigue
  • Gland Issues
  • Hormones
  • Hyperthyroidism
  • Hypopituitarism
  • Hypothyroidism
  • Osteoporosis
  • Thyroid Diseases

Certifications, License, & Education

40 Years Experience

William C. Bayer holds an expired medical license in the state of Illinois.

Medical License

Medical Doctor with an expired medical license in the state of Illinois that expired in 2026.

Education & Training

Fellowship

Completed their fellowship at Loyola University Medical Center in 1991.

Residency

Completed their residency at Loyola University Medical Center in 1989.

Medical School

Graduated from Loyola University Stritch School of Medicine in 1986.

NPI Number

William C. Bayer's NPI number is 1528162898.

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Frequently Asked Questions

Which hospitals is William Bayer affiliated with?
William Bayer is affiliated with Northwestern Medicine Central Dupage Hospital.
How can I make an appointment with William Bayer?
You can find contact information for William Bayer here on Vitals.
Does William Bayer accept virtual/telehealth appointments?
William Bayer has not indicated that they accept virtual/teleheatlh appointments. Contact their office through their Vitals profile to check for availability.
Does William Bayer accept my insurance?
You can see the insurance plans that William Bayer accepts on their Vitals profile.
What languages does William Bayer speak?
William Bayer speaks English and Spanish.

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