Dr Jonathan Katz studied Medicine at Cambridge University from 1985 to 1988 and at University College London from 1988 to 1991. He began his training in Endocrinology in 1994 at St Bartholomew’s Hospital. Dr Katz returned to University College London for specialist registrar training from 1994 to 2001, working at UCL, The Royal Free, and Whittington Hospitals. During this period, he undertook a two-year research fellowship from 1996 to 1998, culminating in an MD Thesis on “Obesity and Polycystic Ovary Syndrome.” In 1999, he worked as a registrar in Sydney, Australia, before starting his career as a Consultant Endocrinologist in the UK in 2001.

Currently, Dr Katz serves as a Consultant Endocrinologist for the Royal Free London NHS Foundation Trust, based at Barnet Hospital. In 2009, he was elected as a Fellow of the Royal College of Physicians (FRCP), an honor granted to consultants who provide the highest standards of care. In 2019, Dr Katz was appointed as Regional Advisor for the Royal College of Physicians, a role that involves supporting training, ensuring new consultant posts meet Royal College standards, appointing College Tutors, and vetting FRCP applications.

Dr Katz has a busy NHS Endocrinology practice, seeing over 300 new patients and more than 1000 follow-up patients each year. He also cares for inpatients at Barnet Hospital with diabetes emergencies and acute endocrine disorders. With over 20 years of experience in diagnosing and treating a wide range of endocrine disorders, Dr Katz is well-equipped to advise and help patients with newly diagnosed problems or those seeking a review of their treatment.

Dr Katz has particular expertise in:

• Managing thyroid disorders including overactive thyroid (thyrotoxicosis)
• Underactive thyroid (Hypothyroidism or Hashimoto’s Thyroiditis)
• Cysts
• Nodules
• Goitre

He also has subspecialty training in reproductive endocrinology, specifically helping patients with Polycystic Ovary Syndrome (PCOS), which can cause symptoms like acne, facial/body hair growth, and irregular periods.

In addition to thyroid and reproductive endocrinology, Dr Katz manages a wide range of hormone problems, including prolactinomas, other pituitary diseases, menopause, adrenal disorders, and testosterone deficiency. Patients often seek his expertise for concerns about hormone imbalances. Dr Katz listens to their symptoms, conducts necessary tests, and recommends appropriate treatments tailored to each patient's needs.

Professional website - http://www.hormoneconsultant.com/

• Thyroid disorders - overactive thyroid, underactive thyroid and thyroid nodules / goitre
• Polycystic ovary syndrome
• Diabetes
• Pituitary disease (e.g. high prolactin level, pituitary tumours)
• Testosterone deficiency; loss of libido in men and women
• Menopause
• Adrenal failure and adrenal tumours

• Fellow of Royal College of Physicians
• Member of Diabetes UK
• Member of Society of Endocrinology