Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — serotonin turnover

Hot flashes, mood instability, brain fog and memory changes during perimenopause are not “all in your head” — but they are very much in your brain. In this in-depth clinical article, Dr. Kate Placzek of ZRT Laboratory explains how declining estradiol disrupts brain glucose metabolism, neurotransmitter signalling and thermoregulation, why perimenopause represents a window of neurological vulnerability, and why the timing of hormone replacement therapy is critical to protecting long-term brain health.

Perimenopause is far more than a reproductive transition — it is fundamentally neurological. As oestradiol declines, the brain’s bioenergetic system becomes compromised, neurotransmitter balance shifts, and the thermoneutral zone narrows, giving rise to hot flashes, mood instability, memory changes and sleep disruption. This article explores the neuroscience behind the menopausal transition and why hormone replacement therapy — timed correctly — may be the most effective intervention.