Menopause is defined by a series of complex biochemical changes, primarily involving a decline in ovarian hormone production. As women transition through perimenopause into menopause, the ovaries gradually reduce their secretion of oestrogen (particularly estradiol) and progesterone. This shift disrupts the finely tuned feedback loop of the hypothalamic-pituitary-ovarian (HPO) axis, leading to increased levels of follicle-stimulating hormone (FSH) and luteinising hormone (LH).
Oestrogen plays a critical role in many biochemical pathways beyond reproduction. Its decline affects thermoregulation in the hypothalamus, contributing to hot flushes and night sweats. It also influences neurotransmitters such as serotonin and dopamine, which can explain mood changes, anxiety, and sleep disturbances commonly experienced during menopause.
Progesterone, known for its calming effects on the nervous system via modulation of GABA receptors, also declines. This reduction can lead to increased feelings of stress, irritability, and disrupted sleep patterns. In addition, changes in oestrogen levels impact insulin sensitivity and fat metabolism, often contributing to weight gain and shifts in body composition.
There are also notable effects on bone metabolism. Reduced oestrogen accelerates osteoclast activity, increasing bone resorption and raising the risk of osteoporosis. Cardiovascular health is similarly affected, as oestrogen supports healthy lipid profiles and vascular function.
Understanding these biochemical changes highlights why menopause can feel so multifaceted. It also reinforces the importance of targeted, supportive interventions to help rebalance systems and promote long-term health and wellbeing.
