Dr. Chang is a board-certified endocrinologist and internal medicine doctor. She is a Clinical Assistant Professor in Stanford Medicine’s Division of Endocrinology, Gerontology, and Metabolism. She specializes in transgender health, pituitary disorders, diabetes, and general endocrine disorders.

She provides patient care at the Stanford Health Care Endocrinology Clinic and the Stanford Health Care LGBTQ+ Health Program. For each patient, she develops a comprehensive, compassionate care plan personalized to individual needs. Her goal is always the best possible health and quality of life for every patient in her care.

Dr. Chang leads quality improvement and education initiatives within the endocrinology and pituitary team. She teaches medical students, residents, and fellows and serves as the endocrinology rotation director for residents and medical students.

Dr. Chang has conducted extensive research and has published peer-reviewed articles on obesity, weight loss, and transgender health in the journals Endocrine Practice, Family Medicine, and Cleveland Clinic Journal of Medicine. She has presented the findings of her research at national meetings of the Endocrine Society and United States Professional Association of Transgender Health.

She is a member of the Endocrine Society, American Association of Clinical Endocrinology, Pituitary Society, and the World Professional Association of Transgender Health.

As a volunteer, Dr. Chang has guided medical students providing health care to uninsured residents of the Bay Area.

When not providing clinical care, teaching, or conducting research, Dr. Chang enjoys time with her family, violin, golf, figure skating, and travel.

She is a native English speaker and also understands Korean.

Clinical Focus

  • Endocrinology
  • Diabetes and Metabolism

Academic Appointments

Administrative Appointments

  • Endocrinology Residency Rotation Director, Stanford University School of Medicine (2022 - Present)

Honors & Awards

  • Early Career Forum Award, Endocrine Society
  • High Value Innovation Challenge Award, Stanford Healthcare
  • Alpha Omega Alpha Honor Medical Society, Stanford University School of Medicine
  • Pituitary Society Master Course for Fellows-in-Training, Pituitary Society
  • Resident Clinical Decision-Making Award, Stanford University School of Medicine
  • Max Miller Award, Case Western Reserve University School of Medicine
  • Ray A and Robert L. Kroc Summer Research Fellowship in Endocrinology, Case Western Reserve University
  • Scholarship, Korean-American Medical Association of Northeast Ohio
  • Intramural Research Opportunities Fellowship, National Institutes of Health – National Institute of Allergy and Infectious Diseases
  • Dean’s Research Fellowship in the Sciences, Yale College
  • Perspectives on Science Research Fellowship, Yale College

Professional Education

  • Board Certification: American Board of Internal Medicine, Endocrinology, Diabetes and Metabolism (2021)
  • Board Certification, American Board of Internal Medicine, Internal Medicine (2019)
  • Fellowship, Stanford University School of Medicine, Endocrinology (2021)
  • Residency, Stanford University School of Medicine, Internal Medicine (2019)
  • Medical Education: Case Western Reserve School of Medicine (2016) OH
  • MD, Case Western Reserve University School of Medicine (2016)
  • BS, Yale University, Biology (2011)

All Publications

  • Severe Posaconazole-Induced Glucocorticoid Deficiency with Concurrent Pseudohyperaldosteronism: An Unfortunate Two-for-One Special. Journal of fungi (Basel, Switzerland) Villar-Prados, A., Chang, J. J., Stevens, D. A., Schoolnik, G. K., Wang, S. X. 2021; 7 (8)


    A 56-year-old Hispanic man with a history of disseminated coccidioidomycosis was diagnosed with persistent glucocorticoid insufficiency and pseudohyperaldosteronism secondary to posaconazole toxicity. This case was notable for unexpected laboratory findings of both pseudohyperaldosteronism and severe glucocorticoid deficiency due to posaconazole's mechanism of action on the adrenal steroid synthesis pathway. Transitioning to fluconazole and starting hydrocortisone resolved the hypokalemia but not his glucocorticoid deficiency. This case highlights the importance of recognizing iatrogenic glucocorticoid deficiency with azole antifungal agents and potential long term sequalae.

    View details for DOI 10.3390/jof7080620

    View details for PubMedID 34436160

  • A RETROSPECTIVE STUDY EXAMINING PHENTERMINE ON PRECONCEPTION WEIGHT LOSS AND PREGNANCY OUTCOMES. Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists Chang, J. J., Lathi, R. B., Kim, S. H. 2020


    Background: Obesity is a well-known risk factor for infertility. However, use of weight loss medications prior to conception is underutilized. The objectives of our study are to describe weight loss, pregnancy rates, and live birth rates after short-term phentermine use in women with obesity and infertility. Methods: This was a retrospective analysis of 55 women (18-45 years old) who were overweight or obese, diagnosed with infertility, and prescribed phentermine for weight loss in an ambulatory endocrinology clinic at a single, tertiary level academic medical center. Main outcome measures were mean percent weight change at 3 months after starting phentermine and pregnancy and live birth rates from start of phentermine to June 30, 2017. Results: Median duration of phentermine use was 70 days (Q1, Q3 [33, 129]). Mean ± SD percent weight change at 3 months after starting phentermine was -5.3 ± 4.1% (p < 0.001). The pregnancy rate was 60% and live birth rate was 49%. There was no significant difference in pregnancy rates (52% vs. 68%, p = 0.23) or live birth rates (44% vs. 54%, p = 0.50) in women who lost ≥5% vs. <5% of their baseline weight. Number of metabolic comorbidities was negatively associated with pregnancy rate. Phentermine was generally well tolerated with no serious adverse events. Conclusions: Phentermine can produce clinically significant weight loss in women with obesity during the preconception period. Higher pregnancy or live birth rates were not observed with greater degree of weight loss with phentermine.

    View details for DOI 10.4158/EP-2019-0609

    View details for PubMedID 32407664



    Weight-loss maintenance following very-low-calorie meal plans is poorly studied. This report describes weight-loss efficacy and predictors of weight-loss maintenance of a ketogenic, very-low-calorie meal plan (protein-sparing modified fast, PSMF) in people with obesity.A total of 127 consecutive adults in the PSMF meal plan (27.2 ± 19.5 weeks) and 48 adults on a conventional, hypocaloric meal plan (23.6 ± 20.8 weeks) were retrospectively studied for percent weight change from baseline to end of intervention and at 6, 12, and 24 months postintervention. Baseline factors were analyzed for correlations with weight-loss maintenance.At end of intervention, weight loss from baseline was greater for the PSMF group compared to the conventional intervention group (-12.4% vs. -2.6%; P<.001) but was similar between groups by 12 months postintervention. PSMF subjects who attended follow-up visits to receive instruction on gradual and limited carbohydrate refeeding after ketosis saw significant weight loss at the end of PSMF compared to those who did not follow-up to receive instruction (-17.5% vs. -8.0%; P<.001) and maintained greater weight loss through 12 months post-PSMF (-9.8% vs. -1.5%; P<.001). Higher baseline body mass index correlated with less weight loss at 12 months post-PSMF (P = .035).PSMF results in effective short-term weight loss of more than 5% from baseline weight. Follow-up for limited carbohydrate refeeding instruction is important for weight-loss maintenance up to 2 years after initial weight loss.BMI = body mass index; PSMF = protein-sparing modified fast.

    View details for DOI 10.4158/EP161383.OR

    View details for PubMedID 28225305

  • A Student-Led Introduction to Lesbian, Gay, Bisexual, and Transgender Health for First-Year Medical Students FAMILY MEDICINE Grosz, A. M., Gutierrez, D., Lui, A. A., Chang, J. J., Cole-Kelly, K., Ng, H. 2017; 49 (1): 52-56


    Lesbian, gay, bisexual, and transgender (LGBT) individuals face significant health disparities. This is in part because many physicians are not sensitive to, and/or are underprepared to address, LGBT-specific concerns. To help meet this need, we, a group of second- and fourth-year medical students with faculty oversight, organized a session on LGBT health for first-year medical students.The three second-year and one fourth-year student authors designed a mandatory session for the 167 first-years at Case Western Reserve University School of Medicine in Cleveland, OH. The 2-hour session consisted of a student-delivered presentation, a patient panel, and a small-group session. Students' LGBT health knowledge and confidence in providing care were assessed anonymously before and after the session, and individuals' pre- and post-session assessments were paired using student-generated identifiers.A total of 73 complete, matched pre-/post-session assessments were received. Students' familiarity with LGBT terminology and demographics increased significantly after the session. Students' perceived preparedness and comfort in providing LGBT-specific care significantly improved in most areas as well. Students strongly praised the session, in particular the patient panel.A student-led educational session on LGBT health can effectively improve first-year medical students' LGBT knowledge and confidence to provide care.

    View details for Web of Science ID 000397087700009

    View details for PubMedID 28166581

  • The protein-sparing modified fast for obese patients with type 2 diabetes: what to expect. Cleveland Clinic journal of medicine Chang, J., Kashyap, S. R. 2014; 81 (9): 557-565


    The protein-sparing modified fast (PSMF) is a very-low-calorie diet containing mostly protein and little carbohydrate. This article reviews the principles of the PSMF and its potential benefits in terms of weight loss, glycemic control, insulin resistance, cardiovascular risk factors, and related complications for patients with type 2 diabetes.

    View details for DOI 10.3949/ccjm.81a.13128

    View details for PubMedID 25183847