Therapeutic window
There is a short window in health when the same decision changes everything. Starting a treatment at 51 rather than 65, acting on bone before it crumbles, supporting the brain before vessels stiffen. That moment when benefit still clearly outweighs risk is the therapeutic window.
Drawn from the re-analysis of a large US study from the 2000s (the WHI trials), the timing hypothesis refers to the interval, most often the first ten years after menopause or before age 60, during which hormone therapy or a foundational intervention keeps its best benefit/risk ratio.
Why timing matters as much as the molecule
While arteries stay supple and the endothelium responsive, oestrogens deliver a clear vasodilator and anti-inflammatory effect. Once atheroma settles in, the same molecules can destabilise the terrain. Same logic for bone: resorption accelerates in the five years following the last period, and every lost year costs several points of mineral density. For the brain, the blood-brain barrier and oestrogen receptors stay functional longer when the transition is supported early.
What is at stake between 50 and 60
The window is not only hormonal. It also covers nutrition (protein, vitamin D, omega-3), muscle strength and sleep, which lay the ground for the decades ahead. Pushing those levers to age 65 means catching up rather than preventing. The decision to start hormone therapy belongs to the physician, but the metabolic ground itself is built from perimenopause onwards.
Related terms
Scientific sources
- Salpeter et al., Systematic review and meta-regression of the timing hypothesis of HRT on mortality, CHD and stroke, 2019
- Oliver-Williams et al., Route, timing, duration and dose of postmenopausal hormone therapy and cardiovascular outcomes, Hum Reprod Update 2019
- US Preventive Services Task Force, Hormone Therapy for Primary Prevention of Chronic Conditions, JAMA 2022