Hormones and Mental Health: What's Actually Going On
If you've read my other posts, you know the theme by now: your hormones don't operate in isolation. Anxiety that shows up out of nowhere, irritability that feels disproportionate to what's actually happening, brain fog, a fatigue that sleep doesn't fix — these are some of the most common things I hear from patients, and they're also some of the most dismissed. "It's probably just stress." Sometimes it is. But there's real, specific physiology behind why hormonal shifts hit your mental state so hard, and understanding it opens up a useful ways to support it.
The Physiology of Anxiety and Irritability
Estrogen and progesterone aren't just reproductive hormones — they're neuromodulators, meaning they directly influence how your brain's chemical messengers behave.
Estrogen has a documented role in the serotonin system, influencing the enzyme (tryptophan hydroxylase) involved in producing serotonin itself. This is part of why the sharp estrogen drop after childbirth, before menstruation, or during the menopausal transition has been described in research as an "estrogen withdrawal state" — a biologically plausible driver of mood symptoms during exactly these windows.
Progesterone's story is more nuanced, and it's genuinely one of the more interesting pieces of hormone physiology. Progesterone is metabolized into a compound called allopregnanolone (ALLO), which positively modulates the GABA-A receptor — your brain's primary calming, inhibitory system. This is generally a good thing: it's part of why progesterone is associated with relaxation and improved sleep. But research has also found that progesterone administration can increase amygdala reactivity — the amygdala being your brain's threat-detection center — in hormone-sensitive individuals, and can worsen mood or anxiety in that same subgroup. In other words, the very same hormone can be calming for one person and activating for another, depending on individual sensitivity. This isn't a contradiction in the research; it's a genuine reflection of why "hormonal anxiety" doesn't look the same for everyone, and why generic advice so often falls short.
Fatigue and Brain Fog: The HPA Axis Connection
Fatigue and brain fog deserve their own explanation, because they're rarely just about hormones in isolation — they're about how your reproductive hormones and your stress-response system interact.
Your hypothalamic-pituitary-adrenal (HPA) axis is the system that governs cortisol release in response to stress. Your hypothalamic-pituitary-gonadal (HPG) axis governs estrogen and progesterone. These two systems share upstream signaling and regulatory overlap in the brain — they are not separate silos. This means chronic stress can disrupt reproductive hormone regulation, and reproductive hormone transitions (postpartum, perimenopause, severe PMS) place real additional load on the HPA axis. When the HPA axis is dysregulated — whether running too hot (elevated cortisol, feeling "wired but tired") or depleted (low cortisol, profound fatigue) — mental clarity and energy are often the first things to suffer, since both systems draw on shared neurological and energetic resources.
This is why fatigue that "doesn't make sense" given your sleep and diet is so often a hormone-and-stress-axis story rather than a single isolated cause — and why testing both reproductive hormones and a cortisol curve together (something we've talked about with DUTCH, salivary testing, and blood tests) gives a much more complete picture than looking at either system alone.
Foundational Nutrients: B Vitamins
B vitamins are essential cofactors for neurotransmitter production — they're literally required for your body to synthesize serotonin, GABA, and dopamine. Despite how essential they are, a large number of people don't get enough through diet alone, particularly B6, B12, and folate — deficiencies that show up as exactly the symptoms we're talking about: low mood, poor concentration, and fatigue.
Vitamin B6 deserves special mention, because your body's demand for it doesn't stay constant — it shifts as your hormones do. Estrogen affects how your body processes tryptophan (the amino acid precursor to serotonin) along the kynurenine pathway, and B6 is a required cofactor at several steps of that pathway. Research on hormonal contraceptive users has repeatedly documented this directly: estrogen-containing contraceptives are associated with a biochemical profile resembling B6 deficiency, altered tryptophan metabolism, and lower levels of a neuroprotective metabolite called kynurenic acid — and this pattern has been specifically linked to the increased risk of mood disturbance seen in some contraceptive users. Similarly, research in pregnancy shows B6 status declining as estrogen rises through gestation. The throughline is consistent: higher or shifting estrogen states increase the body's B6 requirements, and supplementing B6 in these states has been shown in earlier clinical research to meaningfully improve mood symptoms tied to hormonal changes.
Magnesium: Glycinate and Threonate
Magnesium is involved in hundreds of enzymatic processes, including GABA regulation and HPA axis modulation — and it's another nutrient a large portion of the population doesn't get enough of.
A 2017 systematic review in Nutrients examined magnesium supplementation specifically for subjective anxiety, finding a suggestive beneficial effect particularly in people with existing anxiety vulnerability and in premenstrual syndrome specifically — though the review was honest about the overall evidence quality still being limited, and called for better-designed trials.
Magnesium glycinate is bound to the amino acid glycine, which itself has calming, GABA-supportive properties and tends to be well tolerated with less digestive upset than other magnesium forms — a practical reason it's often chosen for anxiety and sleep support specifically.
Magnesium L-threonate is distinct in that it's specifically designed to cross the blood-brain barrier more effectively, since standard magnesium forms have limited ability to raise magnesium levels in brain tissue itself. A 2026 randomized, double-blind, placebo-controlled trial found six weeks of magnesium L-threonate improved cognitive performance in adults, and a separate 21-day RCT found it improved sleep quality and next-day mood and daily function. Given its specific brain-bioavailability profile, threonate tends to be the more targeted choice when concentration and cognitive clarity (rather than general calm) are the primary concern.
L-Theanine for Concentration and Anxiety
L-theanine is an amino acid found in green tea, and it has a very well-documented mechanism: it increases alpha brain wave activity, a pattern associated with a state of calm, alert relaxation — not sedation. This has been demonstrated repeatedly using EEG and MEG brain imaging in controlled trials.
A recent systematic review and meta-analysis of 31 randomized controlled trials (1,168 participants) found that a single 200mg dose significantly improved attention and choice reaction time. A separate randomized trial has shown L-theanine measurably reduces salivary cortisol following an acute stress challenge and decreases perceived stress over longer supplementation periods. L-theanine is also thought to influence GABA, serotonin, and dopamine signaling and to have a regulating effect on the HPA axis itself — which is part of why it works well both for in-the-moment anxiety and as a longer-term support alongside other tools.
Adaptogens and the HPA Axis
Adaptogens are a specific category of herbs defined by a genuinely distinctive property: bidirectional modulation of the HPA axis. Rather than simply sedating or stimulating, they help normalize the stress response in whichever direction it needs to move — calming an overactive stress response, or supporting output in a depleted one. Since the HPA axis is so directly connected to the hormonal symptoms we've covered, this is exactly why adaptogens come up so often in this kind of care.
Ashwagandha has the deepest evidence base of the group. A 2024 systematic review and meta-analysis of nine RCTs (558 participants) found significant reductions in Perceived Stress Scale scores, Hamilton Anxiety Scale scores, and serum cortisol compared to placebo. Its withanolide compounds are thought to modulate the HPA axis directly and interact with GABA-A receptors, contributing to both its anxiolytic and cortisol-lowering effects.
Holy basil (tulsi) works through distinct compounds called ocimumosides, which have been shown to reduce stress-induced corticosterone release and modulate the enzyme 11-beta-HSD1 (involved in activating cortisol at the tissue level). A controlled trial specifically in generalized anxiety disorder found meaningful symptom reduction with tulsi extract, and other trials have documented reduced cortisol alongside improved mood, sleep, and cognitive performance measures.
Licorice root works through a different, complementary mechanism: its compounds inhibit the enzyme 11-beta-HSD2, which normally breaks cortisol down into its inactive form. By slowing that breakdown, licorice effectively extends cortisol's active availability — which makes it a particularly useful adaptogen for the "depleted" end of HPA dysfunction (low cortisol, profound fatigue) rather than the "wired and anxious" end. This is a good example of why adaptogen selection benefits from actually knowing your cortisol pattern rather than guessing.
Reishi and cordyceps round this out from the medicinal mushroom side. A 2026 randomized, double-blind, placebo-controlled trial found a reishi-containing mushroom blend significantly reduced both cortisol and ACTH (the pituitary hormone that signals cortisol release) alongside meaningful reductions in anxiety and physical fatigue over 12 weeks. Reishi specifically has separate trial evidence (132 participants, 8 weeks) for reducing fatigue in people with clinically diagnosed exhaustion-related conditions. Cordyceps is thought to work somewhat further upstream, supporting mitochondrial energy production — which is part of why it's often paired with adrenal-support protocols specifically targeting the fatigue and low-cortisol end of HPA dysregulation, rather than the anxious, high-cortisol end.
Why This All Comes Back to Individualization
Here's the thread running through everything above: the "right" support depends entirely on your specific hormonal and HPA axis pattern, not a generic list of calming herbs. Someone with high, erratic cortisol and racing anxiety needs a very different combination than someone with depleted cortisol and bone-deep fatigue — even though both might describe their experience as "hormonal" and "exhausting."
This is exactly why testing matters as much here as it does for any other hormone concern, and why working with a practitioner who looks at your actual pattern — rather than reaching for the same herb for everyone — makes a real difference in outcomes.
If anxiety, irritability, brain fog, or fatigue have felt hormonal but nobody's been able to explain why, or explain what to actually do about it, I'd love to help you get a clearer picture.
This post is educational and general in nature. It isn't a substitute for individualized medical or psychiatric care. If you're experiencing significant anxiety, mood changes, or thoughts of self-harm, please reach out to your care team or a crisis line for support.
References
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Randomized trial of reishi (Ganoderma lucidum) in 132 participants with neurasthenia, 8-week fatigue outcomes.