The Hormonal Roots of Women’s Mood
If you have spent years being told that your mood changes around your cycle, after pregnancy, or in perimenopause are psychological, a matter of attitude or coping, or simply part of being a woman, this article is a direct rebuttal of that dismissal. The mood shifts that many women experience at specific hormonal moments are not imagined, exaggerated, or a sign of emotional weakness. They are the documented neurological consequence of hormones acting on the brain in ways that are measurable, mechanistic, and increasingly well understood. You deserve to know the biology.
Oestrogen, progesterone, and testosterone all act directly on the brain, influencing neurotransmitter systems that govern mood, stress response, motivation, and emotional regulation. Oestrogen supports the production and activity of serotonin and dopamine. Progesterone converts in the brain to a neurosteroid called allopregnanolone, which acts on GABA receptors to produce calming effects, but in women sensitive to these changes, this same mechanism can trigger anxiety and mood disruption. Fluctuations in these hormones across the menstrual cycle, the perinatal period, and perimenopause produce real changes in brain chemistry, and in some women these changes cross the threshold into clinically significant mood disorders.
Oestrogen’s Role in the Brain
Oestrogen is not only a reproductive hormone. It is a neuroactive steroid that crosses the blood-brain barrier and exerts wide-ranging effects on brain function, particularly in regions involved in mood, memory, and emotional processing.
Serotonin: Oestrogen increases the production of tryptophan hydroxylase, the enzyme that synthesises serotonin. It also upregulates serotonin receptors and reduces the activity of the serotonin transporter (which removes serotonin from synapses), meaning that when oestrogen is present at adequate levels, more serotonin is available for longer in the brain. This is part of why many women notice improved mood, motivation, and emotional resilience in the follicular phase of the cycle, when oestrogen is rising.
When oestrogen falls, as it does in the late luteal phase before menstruation, after childbirth, and during perimenopause, serotonin activity reduces correspondingly. For women with a pre-existing vulnerability in their serotonin system, this reduction can tip into depressive symptoms. This is not a coincidence of timing. It is a direct consequence of oestrogen’s modulatory role.
Dopamine: Oestrogen also influences the dopamine system, which governs motivation, reward, and executive function. Oestrogen enhances dopamine release and receptor sensitivity in the prefrontal cortex and limbic system. Low oestrogen states are associated with reduced dopaminergic activity, which maps onto symptoms of low motivation, anhedonia (the inability to feel pleasure), and poor concentration that many women report in the premenstrual phase and in perimenopause.
GABA: Oestrogen has a complex relationship with gamma-aminobutyric acid (GABA), the brain’s primary inhibitory neurotransmitter, which is central to anxiety regulation. Higher oestrogen levels generally support GABAergic tone, contributing to a calmer baseline state. Falling oestrogen reduces this support.
Progesterone and Allopregnanolone
Progesterone’s effects on mood are mediated largely through its conversion in the brain to a neurosteroid called allopregnanolone (also called ALLO or 3-alpha,5-alpha-tetrahydroprogesterone). Allopregnanolone is a potent positive modulator of the GABA-A receptor, the primary target of GABA in the nervous system. When allopregnanolone acts on GABA-A receptors, it enhances GABA signalling, producing sedating, anxiolytic effects. At steady, adequate levels, progesterone’s conversion to allopregnanolone generally produces a calming effect.
The problem, for a significant subset of women, is not the allopregnanolone itself but the sensitivity of the GABA-A receptor to its fluctuation.
The GABA-A Receptor Sensitivity Hypothesis for PMDD
Premenstrual dysphoric disorder (PMDD) is a severe mood disorder occurring in the luteal phase of the menstrual cycle, characterised by profound depression, anxiety, irritability, and emotional dysregulation that resolve within days of menstruation beginning. It affects approximately 3 to 8 percent of women of reproductive age and causes significant functional impairment.
For decades, PMDD was poorly understood. Women with PMDD do not generally have abnormal hormone levels; their oestrogen and progesterone measurements are often within the same range as women who do not have PMDD. This ruled out simple hormone excess or deficiency as the explanation.
Current research points strongly to differential sensitivity in the GABA-A receptor system. The hypothesis, supported by substantial evidence from clinical and neuroimaging studies, is that in women with PMDD, the GABA-A receptor does not adapt normally to fluctuating allopregnanolone levels across the luteal phase. In women without PMDD, the receptor adjusts to rising and falling allopregnanolone as the cycle progresses. In women with PMDD, this adaptation fails. The result is that normal luteal-phase fluctuations in allopregnanolone, rather than producing the expected calming effect, produce paradoxical anxiety, irritability, and mood instability.
Supporting this model: studies in women with PMDD have shown that artificially suppressing the normal hormonal cycle with GnRH analogues eliminates PMDD symptoms entirely, even though the hormones being suppressed are within the normal range. When progesterone is added back alone, PMDD symptoms return. This demonstrates that the problem is the cycle of fluctuation itself, and the abnormal neurological response to it, rather than hormone levels per se.
This research has significant clinical implications. PMDD is increasingly being framed as a neurobiological disorder of hormone sensitivity rather than a psychiatric disorder in the traditional sense, which points towards targeted treatments including SSRIs (which affect allopregnanolone’s downstream signalling pathways as well as serotonin), hormonal suppression, and a newly approved synthetic neurosteroid called zuranolone, developed specifically on the basis of this receptor sensitivity model.
Testosterone in Women
Testosterone is present in women at lower concentrations than in men, but it is biologically active and plays a meaningful role in mood, motivation, libido, and cognitive function. Testosterone contributes to dopaminergic activity and supports the drive, confidence, and energy that many women associate with the pre-ovulatory phase of their cycle, when testosterone is at its monthly peak alongside oestrogen.
Testosterone levels decline with age, falling most steeply in the decade before menopause. Low testosterone in women is associated with reduced motivation, persistent fatigue, low libido, and in some women, depression that does not respond fully to standard antidepressants. Testosterone therapy for women remains underresearched and is used primarily for low libido, but growing evidence suggests its role in mood and wellbeing warrants further investigation.
Menopause and Mood
Perimenopause, the transition period leading to the final menstrual period, is now recognised as a specific window of increased depression risk, including in women with no previous psychiatric history. The hormonal driver is oestrogen instability: in perimenopause, oestrogen does not decline gradually and steadily. It fluctuates erratically, sometimes swinging from high to low within a single cycle. This instability, rather than low oestrogen per se, is thought to drive mood dysregulation in many perimenopausal women, by creating the same kind of rapid neurochemical shifts that the GABA-A receptor sensitivity model describes for PMDD.
After menopause, when oestrogen stabilises at a consistently low level, some women find their mood actually improves, even though oestrogen is lower than ever. This paradox fits the instability hypothesis: it is the fluctuation, not simply the low level, that drives the disruption.
Hormone replacement therapy (HRT) containing oestrogen can be highly effective for perimenopausal mood symptoms, particularly depression and anxiety linked to hormonal instability, though the decision to use HRT involves a broader discussion of individual risk and benefit with a healthcare provider.
FAQ
Why do some women feel better on certain parts of their cycle?
Oestrogen peaks in the late follicular phase, just before ovulation, enhancing serotonin and dopamine activity and supporting GABA tone. Many women notice improved mood, energy, and motivation during this phase. The post-ovulatory rise in progesterone initially has a calming effect through allopregnanolone. The late luteal phase, when both hormones fall before menstruation, is when neurochemical support is lowest, explaining the mood dip many women notice.
Is PMDD a hormonal disorder or a psychiatric disorder?
Current evidence positions PMDD as a neurobiological disorder of sensitivity to normal hormonal fluctuation rather than a disorder caused by abnormal hormone levels. Women with PMDD have typical progesterone and oestrogen levels; their brain’s response to allopregnanolone fluctuation is atypical. This distinction matters for treatment: suppressing the hormonal cycle can eliminate symptoms entirely, and treatments targeting the GABA-A receptor pathway are showing promise. It is not a psychiatric weakness or a purely psychological response to stress.
Can antidepressants help hormone-related mood symptoms?
SSRIs are an established first-line treatment for PMDD, with evidence showing they work faster in PMDD than in typical depression, often within days rather than weeks. This supports a mechanism linked to their effects on allopregnanolone signalling rather than just serotonin reuptake. For perimenopausal depression, SSRIs can be effective, though oestrogen therapy also has strong evidence. The most appropriate approach depends on the individual’s full hormonal picture and should be discussed with a healthcare provider.
Does low testosterone affect mood in women?
Yes. Testosterone supports dopaminergic activity in women and contributes to drive, motivation, and emotional resilience. Lower testosterone levels, which occur naturally with age and drop sharply in surgical menopause, are associated in some women with persistent fatigue, low motivation, reduced libido, and mood that does not fully respond to standard treatments. Testosterone therapy for women is used in some healthcare systems for loss of sexual desire and is being increasingly studied for broader wellbeing outcomes.
Your Mood Is Not All in Your Head. It Is in Your Hormones. Mayno Helps You Understand Both.
The biology of hormonal mood is real, measurable, and increasingly treatable. If you have ever been dismissed when trying to describe what happens to your mood at specific points in your cycle or your life, Mayno is here to give you the evidence to understand what is happening and the knowledge to advocate for the care you need.
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This article is for informational purposes only and does not constitute medical advice. If you are experiencing mood symptoms linked to your hormonal cycle or life stage, please consult a qualified healthcare professional. Mayno Health does not replace clinical care.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
