How should glucocorticoid and mineralocorticoid replacement be optimised in a young patient with classic 21-hydroxylase congenital adrenal hyperplasia?

This article aims to provide a simple clinical approach to understanding and managing steroid supplementation in young adults and adult patients with classical congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency (21OHD). It aims to overcome the clinical inertia that leads to glucocorticoid excess in these patients, particularly addressing the adult endocrinologist at the transition when they meet the patient with 21OHD with 'fresh eyes'.