Anxiety is not driven by a single hormone but by an overlapping web of chemical messengers, each affecting the brain and body in distinct ways. Cortisol, adrenaline, and corticotropin-releasing hormone (CRH) tend to get the most attention because they sit at the center of the body’s acute stress machinery, but thyroid hormones, sex hormones, gut peptides, and even hormones released by fat tissue all shape how anxious a person feels on any given day. Some of these hormones ramp anxiety up directly, while others normally keep it in check and cause problems only when their levels drop or fluctuate.
Cortisol and the Stress Axis
Cortisol is the hormone most people associate with stress, and the link to anxiety is real. A Mendelian randomization study using genetic variants that influence cortisol levels found that higher cortisol was associated with increased odds of anxiety, with a pooled odds ratio of about 1.16 per standard-deviation increase in cortisol. Interestingly, the same study found no such association with major depression or neuroticism, suggesting cortisol’s relationship with anxiety is somewhat specific.1PubMed Central. Assessing the Role of Cortisol in Anxiety, Major Depression, and Neuroticism: A Mendelian Randomization Study Using SERPINA6 / SERPINA1 Variants
Clinical data support this. Older adults with generalized anxiety disorder have been shown to have higher peak cortisol levels than healthy controls. When those patients were treated with the SSRI escitalopram, the ones who started with the highest cortisol saw the biggest reductions, both in cortisol and in anxiety symptoms. Patients whose cortisol was already in the lower range did not see the same benefit, hinting that for some people, the cortisol elevation itself is a meaningful driver of their symptoms rather than just a bystander.2PubMed Central. Elevated cortisol in older adults with Generalized Anxiety Disorder is reduced by treatment: a placebo-controlled evaluation of escitalopram
Cortisol does not act alone, though. Its effects depend partly on how well the body’s receptors respond to it. Research measuring glucocorticoid receptors on immune cells found that receptor number and cortisol output tend to be inversely related across mood and anxiety disorders, but the relationship is messy and does not always reach statistical significance. Receptors appear to be modulated by multiple factors, not just how much cortisol is floating around.3PubMed. Glucocorticoid receptor number and cortisol excretion in mood, anxiety, and psychotic disorders
CRH and Norepinephrine, the Upstream Triggers
Before cortisol ever enters the bloodstream, the brain has already sounded the alarm using corticotropin-releasing hormone. CRH neurons in the central amygdala are a particularly important population. Animal research has shown that directly activating these neurons increases anxiety-like behavior across multiple laboratory tests, and that blocking CRH receptors with an antagonist drug completely reverses the effect.4PubMed Central. The Central Amygdala Corticotropin-releasing hormone (CRH) Neurons Modulation of Anxiety-like Behavior and Hippocampus-dependent Memory in Mice
CRH neurons in the amygdala project to an area called the locus coeruleus, which is the brain’s main source of norepinephrine (the central-nervous-system version of adrenaline). When CRH hits these norepinephrine neurons at a high rate, the result is a tonic state of arousal that produces aversion and anxiety-like behavior similar to what direct stress causes. Blocking the CRH receptor at that junction completely shuts down the anxious response, confirming that CRH release onto norepinephrine neurons is a causal link in stress-driven anxiety.5Neuron. Norepinephrine and Corticotropin-Releasing Hormone: Partners in the Neural Circuits that Underpin Stress and Anxiety This CRH-norepinephrine partnership explains why anxiety so often comes with the physical symptoms of arousal: a pounding heart, sweaty palms, and the feeling that you cannot sit still.
Adrenaline and the Body’s Fight-or-Flight Chemistry
Adrenaline (epinephrine) is released by the adrenal glands into the bloodstream in response to perceived threats and acts as the body’s emergency accelerator. It increases heart rate, dilates airways, and redirects blood toward muscles. In people prone to panic, the effects can spiral. Research administering epinephrine by infusion found that patients who developed panic attacks in response showed a greater cardiovascular response and a sharper drop in carbon dioxide levels than those who did not panic.6Journal of Psychiatric Research. Epinephrine-induced panic attacks and hyperventilation
What makes adrenaline tricky is the feedback loop. The physical sensations it produces, like a racing heart and hyperventilation, can themselves become the trigger for more anxiety, especially in people with panic disorder. Someone who misinterprets a pounding heart as a sign of a heart attack gets another burst of adrenaline in response to the fear, which makes the physical symptoms worse. This cycle is a core feature of panic attacks and one reason cognitive behavioral therapy focuses so heavily on reinterpreting bodily sensations.
Thyroid Hormones
An overactive thyroid pumps out excess thyroid hormone, and the result can look almost identical to an anxiety disorder. Palpitations, tremors, restlessness, trouble sleeping, and a persistent sense of nervousness are classic hyperthyroid symptoms. Because the overlap is so convincing, misdiagnosis happens. A published case report describes a 33-year-old woman who was initially diagnosed with generalized anxiety disorder and treated accordingly, only to be correctly diagnosed with hyperthyroidism on further evaluation.7PubMed Central. Hyperthyroidism Masquerading as an Anxiety Disorder: A Report on a Misdiagnosed Case
Thyroid hormones raise the body’s metabolic rate and amplify the sensitivity of the nervous system to catecholamines like adrenaline. The practical takeaway is that anyone presenting with new or worsening anxiety, particularly if it comes with weight loss, heat intolerance, or a visible tremor, should have thyroid function checked before being started on psychiatric medications alone. Treating the thyroid problem often resolves the anxiety.
Sex Hormones and Neurosteroids
Estrogen, progesterone, and testosterone all influence anxiety, but not in simple “more is better” or “more is worse” ways. The effects depend heavily on timing, fluctuation, and context.
Progesterone’s breakdown product allopregnanolone is one of the body’s most powerful natural calming agents. It works by boosting the activity of GABA-A receptors, the same receptors targeted by drugs like benzodiazepines. Low levels of allopregnanolone have been found in people with major depression, anxiety disorders, and premenstrual dysphoric disorder.8PubMed. The role of allopregnanolone in depression and anxiety But the relationship is not as simple as “more allopregnanolone equals less anxiety.” When the brain is exposed to allopregnanolone continuously, as happens during certain phases of the menstrual cycle or during pregnancy, tolerance develops. The GABA-A receptor changes its subunit composition, becoming less sensitive, and the calming effect weakens.9PubMed Central. Tolerance to allopregnanolone with focus on the GABA-A receptor This tolerance mechanism helps explain why some women experience spikes in anxiety at specific points in their cycle, or during the postpartum period when allopregnanolone levels drop suddenly after months of elevation.
Estrogen interacts with serotonin signaling in ways that matter for anxiety treatment. Research has shown that estrogen can partially desensitize serotonin 1A receptors in the hypothalamus, producing changes that overlap with what SSRIs do.10PubMed Central. Estradiol induces partial desensitization of serotonin 1A receptor signaling in the paraventricular nucleus of the hypothalamus and alters expression and interaction of RGSZ1 and Gz This may be one reason anxiety and depression rates shift across the menstrual cycle and around menopause, when estrogen levels swing or decline.
Testosterone also plays a role, particularly in men. Low testosterone is linked to various forms of anxiety, from unfocused fearfulness to outright panic, and testosterone replacement in men with clinically low levels has been shown to reduce anxiety and improve quality of life.11PubMed. Testosterone, mood, behaviour and quality of life A review of the literature on hypogonadism found that low testosterone is one of the key factors behind worsening emotional well-being in affected men, and that replacement therapy leads to meaningful improvements in anxiety regardless of the type of hypogonadism.12Health of Man. Social Adaptation and Anxiety Levels in Patients with Hypogonadism: the Impact of Hormonal Status (Literature review) Testosterone appears to work partly through enhancing stress resilience and shifting how the brain processes threats and rewards.
Gut Peptides That Reach the Brain
The gut produces hormones that do far more than regulate digestion. Two stand out for their role in anxiety: cholecystokinin (CCK) and ghrelin.
CCK is released by the small intestine in response to food, but a small fragment of it, known as CCK-4, is one of the most reliable ways to provoke a panic attack in a laboratory setting. Injected intravenously, CCK-4 triggers dose-dependent panic symptoms in both panic disorder patients and healthy volunteers.13PubMed Central. Cholecystokinin and Panic Disorder: Reflections on the History and Some Unsolved Questions14European Neuropsychopharmacology. The panic-inducing properties of the cholecystokinin tetrapeptide CCK4 in patients with panic disorder The CCK-4 panic challenge has become a standard research tool for studying panic pharmacology. Drugs that boost the calming neurotransmitter GABA, for instance, markedly reduce CCK-4-induced panic, reinforcing the connection between these chemical systems.15PubMed. Vigabatrin decreases cholecystokinin-tetrapeptide (CCK-4) induced panic in healthy volunteers
Ghrelin, often called the “hunger hormone,” acts on receptors in the prefrontal cortex and has a surprising role in anxiety. After repeated stress exposure, the ghrelin receptor is upregulated on excitatory neurons in the prefrontal cortex, which disrupts the balance between excitation and inhibition and promotes anxiety-related behavior. When researchers knocked down the ghrelin receptor in those same neurons, the anxiety effect was blocked.16PubMed Central. Stress-induced GHS-R1a expression in medial prefrontal cortical neurons promotes vulnerability to anxiety in mice This finding is still early-stage, but it suggests that the metabolic state of the body, including how hungry or fed you are, can influence anxiety vulnerability at the level of brain wiring.
Oxytocin and Vasopressin
Oxytocin is often marketed as the “love hormone” or “cuddle hormone,” and it does have calming effects under the right conditions. But its relationship with anxiety is more complicated than popular accounts suggest. Research indicates that in safe, positive social contexts, oxytocin can dampen the stress response and promote well-being. In hostile or threatening situations, however, it may do the opposite: enhancing attention to negative social cues, increasing distress, and worsening perceptions of others.17Psychoneuroendocrinology. The role of oxytocin in social bonding, stress regulation and mental health: An update on the moderating effects of context and interindividual differences The context-dependence means oxytocin is not a straightforward anti-anxiety molecule. For someone in a supportive relationship, it likely helps. For someone navigating a threatening social environment, it could make things worse.
Vasopressin, a closely related peptide, leans more clearly toward promoting anxiety. Both vasopressin and CRH have been shown to contribute to anxious and depressive behavior, partly through their shared influence on the stress hormone axis.18PubMed Central. Interaction of stress, corticotropin-releasing factor, arginine vasopressin and behaviour Brain imaging work in animals has found that blocking vasopressin V1a receptors changes the neural response to threatening stimuli like predator odors, suggesting vasopressin shapes how the brain registers danger.19PubMed Central. Predator odor-evoked BOLD activation in the awake rat: modulation by oxytocin and V₁a vasopressin receptor antagonists
Hormones That Push Back Against Anxiety
Not every hormonal signal amplifies anxiety. Some actively counteract it, and knowing about them clarifies the picture. Atrial natriuretic peptide (ANP), a hormone released by the heart when its chambers stretch, has anxiolytic properties. In a study using CCK-4 to provoke panic attacks, pretreatment with ANP reduced the number of panic attacks in both patients and healthy controls, lowered panic symptom scores, and blocked the CCK-4-triggered release of stress hormones. ANP also inhibited the sympathetic nervous system activation that CCK-4 normally causes.20JAMA Psychiatry. Anxiolyticlike Effects of Atrial Natriuretic Peptide on Cholecystokinin Tetrapeptide–Induced Panic Attacks: Preliminary Findings ANP is not something you take as a supplement, but its existence illustrates that the body has built-in counter-regulatory hormones that actively oppose panic, and that anxiety is the product of the balance between anxiety-promoting and anxiety-dampening signals.
Prolactin, Leptin, and Vitamin D
Several hormones with primary roles outside the stress system still show meaningful associations with anxiety. Prolactin, best known for its role in milk production, is also a stress-responsive hormone that acts within the brain to influence mood. Among women with major depression, prolactin levels were positively correlated with anxiety scores.21PubMed Central. Plasma prolactin is higher in major depressive disorder and females, and associated with anxiety, hostility, somatization, psychotic symptoms and heart rate Whether prolactin directly worsens anxiety or simply rises alongside it as part of the body’s stress response remains unclear. Prolactin is considered an adaptive hormone that modulates stress responses and neurogenesis, but disruptions in its system could contribute to pathological behavioral outcomes.22PubMed Central. Actions of Prolactin in the Brain: From Physiological Adaptations to Stress and Neurogenesis to Psychopathology
Leptin, a hormone produced by fat cells that normally signals satiety to the brain, shows up in the anxiety story as well. In patients with type 2 diabetes, high leptin levels and leptin resistance were associated with moderate-to-severe anxiety symptoms.23PubMed. Correlations of serum leptin and leptin resistance with depression and anxiety in patients with type 2 diabetes Leptin resistance means the brain stops responding properly to leptin’s signals, a state common in obesity. Whether normalizing leptin function would improve anxiety in these patients is still an open question, but it underscores how deeply metabolic health and mental health are intertwined.
Vitamin D, technically a secosteroid hormone the body synthesizes from sunlight, has also been linked to anxiety. A review of the evidence found that low vitamin D levels are associated with increased symptoms of both depression and anxiety, possibly through mechanisms involving oxidative stress and inflammation.24PubMed Central. Is Vitamin D Important in Anxiety or Depression? What Is the Truth? The association is consistent enough that checking vitamin D levels is reasonable for anyone dealing with persistent anxiety, though supplementation trials have produced mixed results and the relationship may not be straightforwardly causal.
Blood Sugar Swings and Anxiety
Insulin itself is not typically classified as an anxiety-causing hormone, but the hormonal cascade triggered by blood sugar instability can produce anxiety that feels indistinguishable from a psychiatric disorder. A published case report described a patient with generalized anxiety disorder whose symptoms improved substantially when she modified her diet to include more protein, fat, and fiber, stabilizing her blood sugar. When she briefly returned to her previous diet, the anxiety symptoms came back.25PubMed Central. Generalized Anxiety Disorder and Hypoglycemia Symptoms Improved with Diet Modification Hypoglycemia triggers the release of adrenaline and cortisol as the body scrambles to raise blood sugar, and those counter-regulatory hormones produce the classic anxiety symptoms: shakiness, racing heart, sweating, and dread. For people whose anxiety worsens between meals or after eating high-sugar foods, this metabolic mechanism is worth investigating.
Hormonal Contraceptives and Mood
Synthetic hormones in oral contraceptives can influence anxiety and depression risk, though the effects vary by formulation and age group. A review of the evidence found that progestin-only pill users had a modestly higher risk of depression compared to non-users, and the risk was consistently higher among adolescents aged 15 to 19.26PubMed Central. Oral Contraceptives and the Risk of Psychiatric Side Effects: A Review The mechanisms likely involve the ways synthetic progestins interact with GABA-A receptors and neurosteroid metabolism. Since natural progesterone’s breakdown product allopregnanolone is calming, synthetic progestins that do not convert into the same calming metabolites may leave the brain without its usual buffer. This does not mean hormonal contraception is unsafe, but it does mean that mood changes on birth control should be taken seriously and discussed with a prescriber rather than dismissed.
Puberty and the Adolescent Brain
The hormonal surges of puberty represent a unique window of vulnerability for anxiety. The rising levels of sex steroids, including testosterone and estrogen, reshape brain circuits involved in emotion processing at the same time that social pressures intensify. Research has found that the physical maturation linked to puberty affects brain development, social cognition, and peer relationships, all of which are independently associated with mood and anxiety disorder risk.27PubMed Central. Puberty Initiates Cascading Relationships Between Neurodevelopmental, Social, and Internalizing Processes Across Adolescence
The vulnerability is not evenly distributed. A study of adolescent girls found that the connection between the prefrontal cortex and the amygdala, a circuit critical for regulating fear, was associated with anxiety symptoms only in girls who were more advanced in pubertal development. In girls earlier in puberty, the same brain circuit did not predict anxiety. Testosterone levels and adrenarcheal development moderated this relationship, suggesting that sensitivity to how pubertal hormones alter brain connectivity could contribute to anxiety disorder risk, particularly in girls.28PubMed Central. Fronto-amygdala resting state functional connectivity is associated with anxiety symptoms among adolescent girls more advanced in pubertal maturation This helps explain why anxiety disorders so often emerge or worsen during the teenage years, and why the gender gap in anxiety prevalence, with women affected roughly twice as often as men, opens up at puberty rather than being present from birth.