The hot flush in a meeting is public. Everyone watches. The three in the morning has no witnesses, so nobody counts it. Between forty and fifty-six percent of women report insomnia symptoms in the transition, and one in four meets full diagnostic criteria. This is what is happening in those hours, why progesterone leaving is the part nobody explains, and why the treatment with the strongest evidence behind it is almost never the one you get offered.

Four men were laughing about their "hormonal" wives when the only woman at their level crossed the room, dropped her jacket on the floor, and showed them the sleeves she'd cut out of her blouse. Perimenopause hormones do not fade on a gentle slope. FSH rises first, estradiol spikes higher than it did at twenty-five, and progesterone leaves years before anyone mentions menopause. What is actually happening, why a single blood test cannot see it, and what the evidence says helps.

There is a specific week of the month where everything becomes harder. Not harder the way Monday is harder than Friday. A different kind of harder — where tasks that were manageable seven days ago now require effort that feels unreasonable, where you lose your keys three times before 10am. If you have ADHD, that week is not a coincidence. It is your dopamine system responding to a hormonal signal nobody told you about.

Your body has been drawing a temperature map every single month. Low phase, thermal shift, sustained luteal high, pre-menstrual descent — month after month, whether anyone was looking or not. October is the best time to start looking.

I spent the better part of my twenties thinking my body was unpredictable. One week sharp and focused, the next week foggy and tender — craving different food, needing more sleep, finding the same social situation that felt easy a fortnight ago now unexpectedly exhausting. It took years before I understood that what I was experiencing was not randomness. It was a programme. A 28-day biological programme that was running, flawlessly, every single month. Nobody gave me a map. So I built one.

There is a specific version of summer dread I have felt every year since I was a teenager. It is not the heat. It is the swimsuit. More precisely: it is standing in front of a mirror and having the number on the scale still running in the background of my brain. What I now understand is that my body was not bigger because of anything I did. It was cycling. And that changes everything.