TJC Accredited
3 consecutive terms
(Friday, February 6, 2026; Dededo, Guam) – Guam Regional Medical City (GRMC) is proud to welcome Dr. Joel Marc Rubio, Guam’s first endocrinologist and a highly respected physician well known throughout the island’s medical community, to its growing network of specialty physicians. While Guam is now served by multiple endocrinology providers, Dr. Rubio holds the distinction of being the island’s first specialist in the field. Dr. Rubio brings decades of experience and a deep commitment to advancing endocrine care for the people of Guam.
Dr. Rubio earned his Doctor of Medicine from the University of Santo Tomas in Manila, Philippines, where he completed his Internal Medicine residency and served as Chief Resident. He then pursued further specialized training through an Endocrinology fellowship at the University of California, San Francisco (UCSF) and a Clinical Neuroendocrinology fellowship at the UCSF Pituitary Center. Dr. Rubio is board-certified in Internal Medicine and Endocrinology, Diabetes, and Metabolism.
Dr. Rubio completed advanced postgraduate training in areas such as thyroid ultrasound and biopsy, obesity medicine, nuclear medicine in endocrinology, and procedural medicine. He earned his Doctor of Medicine degree from the University of the East–Ramon Magsaysay Memorial Medical Center in the Philippines, completed his Internal Medicine residency at Saint Barnabas Hospital under the Cornell University Training Program in New York, and went on to complete his Endocrinology fellowship at the State University of New York at Stony Brook Medical Center.
Throughout his distinguished career, Dr. Rubio has held leadership and academic roles in both Guam and the continental United States. He was the Founding Partner and Head of Clinical Services at Health Partners, LLC, and has contributed to medical research, physician education, and leadership within professional organizations. As a long-standing provider in Guam, he is widely recognized for his contributions to endocrine care and medical leadership on the island.
“Dr. Rubio’s expertise and long-standing dedication to Guam’s medical community reflect our commitment to providing specialized, high-quality care close to home,” said Barbiejane Ubay, BHA, CSAPM, GRMC Clinic Manager, Outpatient Specialty Services. “His presence at GRMC enhances access to critical endocrine services for our patients and supports better long-term health outcomes for our island.”
Now practicing at GRMC, Dr. Rubio continues his mission of patient-centered care, working collaboratively with multidisciplinary teams to support prevention, early diagnosis, and advanced treatment for endocrine and metabolic conditions.
Individuals seeking consultation or treatment are encouraged to first consult with their primary care physician to determine if a referral to GRMC would be beneficial. Patients are also advised to contact their health insurance
provider to confirm coverage for any recommended procedures.
Visit GRMC’s website to learn more about Dr. Rubio and endocrinology services:
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