The idea that the effects of menopausal hormone therapy depend on how close to menopause it is started.
Also known as: timing hypothesis
The critical window (or timing) hypothesis proposes that the balance of potential benefits and risks of menopausal hormone therapy differs depending on age and how many years past menopause a person is when they start.
It informs discussions about the timing and route of hormone therapy, which are individualized with a clinician.