OestrogenEstrogen · Oestradiol · Estradiol
The principal female sex hormone, also important for bone, brain and vascular health in everyone.
Oestrogen is the group of hormones, chiefly oestradiol, that drive female reproductive development and the menstrual cycle. It is present and functionally important in men too, produced from testosterone by the enzyme aromatase, where it contributes to bone health, libido and cardiovascular function.
Its reach goes well beyond reproduction. Oestrogen restrains the cells that break bone down, supports vascular function, influences fat distribution and body composition, and affects mood, sleep and thermoregulation. That breadth is why the menopause produces such a wide symptom list rather than a narrow one.
Bone is where the loss is most measurable. Density falls sharply in the years around the menopause as oestrogen declines, which is the single biggest driver of osteoporosis risk in women, and the reason heavy resistance and impact training becomes more valuable at exactly the point it is usually discouraged.
For training, the practical implication is smaller than the internet suggests. The largest meta-analysis on cycle phase and performance found at most a trivial average reduction in the early follicular phase, with wide variation between individuals and studies, and the authors argued against general guidelines on the basis of their own findings.
That is not the same as saying symptoms do not matter. Heavy bleeding, pain and disrupted sleep affect training substantially, and planning around how you actually feel beats planning around a phase timetable.
Hormone therapy is the most effective treatment for hot flushes and night sweats, and the decision is individual and clinical. Supplements claiming to balance oestrogen are a large, aggressively marketed category with small and inconsistent results.
In practice, train consistently, adjust for symptoms rather than dates, prioritise heavy loading for bone, and take menopause management to a clinician.