Estrogen, progesterone, testosterone, FSH. What they supported, what happens when they fall or fluctuate, and what replacing does and doesn't do. No scare, no sell.
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Three hormones, three different jobs
Free to read and save here. No account needed. Grades apply to the named evidence, not your personal treatment eligibility.
Estrogen
Grade B
Estrogen supports bone and genital tissues and acts in brain networks involved in temperature, memory and attention. Research suggests links with dopamine signalling, but that doesn’t mean estrogen replacement reliably fixes brain fog.
What replacing can and can't do
Systemic MHT treats hot flashes and prevents bone loss. It isn’t recommended to prevent dementia. Local vaginal estrogen targets dryness, irritation and some urinary symptoms.
Grade B is a cautious overview label; dopamine mechanisms are less certain than bone and hot-flash treatment evidence.
Progesterone changes after ovulation. Its metabolites act on brain signalling involved in sleep and mood. Responses differ: some people feel calmer; others are sensitive to changes.
What replacing can and can't do
Micronized progesterone may improve some sleep outcomes. When systemic estrogen is used with a uterus, a progestogen usually protects the uterine lining. It isn’t a guaranteed mood or sleep treatment.
Grade B for sleep outcomes; small trials and different formulations limit certainty.
Testosterone contributes to sexual function and muscle biology. It tends to change with age rather than follow a single menopause drop. Both-ovary removal can change that picture.
What replacing can and can't do
The supported treatment indication is persistent, distressing low desire after menopause, following assessment. Trials don’t establish testosterone as a treatment for muscle gain, brain fog, mood, bone density or general energy.
Grade B for the focused low-desire discussion, not a muscle-building or energy claim.
Perimenopause often brings fluctuating estrogen and less predictable ovulation. Lower estrogen becomes more sustained after menopause. Symptoms have other causes too.
Estrogen fluctuates, then falls
Temperature regulation, brain networks, bone and genital tissues
Hot flashes, brain fog, interrupted sleep, dryness and bone loss
Ovulation becomes less predictable
Progesterone patterns change; sleep and mood signalling can be affected
Sleep and mood changes vary. Other causes still deserve attention
FSH often rises
The brain sends a stronger signal as ovarian feedback changes
FSH is a signal, not a symptom. A single test often can’t explain perimenopause
A simplified pathway, not a test of what caused your symptoms. Genital and urinary changes are sometimes called GSM. Sources: NICE NG23 and Brinton et al., 2015.
