Mark S. Mclean is an endocrinologist based in Sydney, NSW, Australia.
He looks after people with hormone and gland conditions, from babies through to adults. Hormones help control things like growth, blood sugar, blood pressure, energy levels, and how the body uses food. When hormones get out of balance, it can affect many parts of life at once, so Mark focuses on getting the story right first, then guiding the next steps.
In many cases, his patients come with problems linked to the pituitary and other hormone pathways. This can include pituitary tumours, pituitary apoplexy, and hypothalamic tumours. He also treats conditions like acromegaly and Cushing’s disease, along with growth hormone deficiency and hypogonadism. Some families seek help for infant and newborn hormone-related issues, including low blood sugar and severe early health concerns like infant respiratory distress syndrome.
Blood sugar care is also a big part of the work. Mark manages both Type 1 and Type 2 diabetes, plus related issues like low blood sugar and infant hyperglycaemia. He also helps with gestational diabetes during pregnancy, including monitoring and ongoing planning to support both mum and baby.
He sees people with wider hormone and immune-related disorders as well. This can include autoimmune conditions such as APECED and Autoimmune Polyglandular Syndrome Type 2. In some cases, people have issues like vitamin B12 deficiency anaemia, or changes in skin and hair that may link back to hormone imbalances.
There are also other conditions in the mix, depending on the patient. Mark treats obesity when hormones or gland problems may be part of the picture. He works with people dealing with high blood pressure, including hypertension in infants. He also manages conditions such as ovarian hyperstimulation syndrome and premature ovarian failure, and for some patients prostate cancer care can overlap with hormone management.
Along the way, he aims to keep care steady and practical. Endocrine conditions can be complex, and results don’t always come quickly, so follow-up and clear explanations matter. Mark works with his patients to understand symptoms, test results, and treatment options in everyday language, so the plan feels manageable.
Mark is based in Sydney and works with a team approach where needed, including coordination with other specialists and local care providers. He uses current clinical practice guidelines and standard treatment pathways to help guide decisions, and he stays focused on safe, careful care for each person and their situation.
