Irritability and serotonin

Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD) are conditions that cause emotional, physical, and digestive symptoms in the days leading up to menstruation.

Serotonin plays a key role in PMS/PMDD because:

• It regulates mood and emotional stability

• It controls pain perception and sensitivity

• It affects gut function (constipation, diarrhea, bloating)

• It interacts with estrogen and progesterone

Since you have PCOS, IBS-D, and high prolactin, serotonin imbalances may worsen PMS, mood swings, and digestive symptoms. Understanding the serotonin-PMS connection can help you reduce symptoms naturally.

How does Serotonin Affect PMS & PMDD?

✔ Serotonin drops before menstruation, causing:

• Irritability, anxiety, and depression

• Fatigue and low energy

• Increased pain sensitivity (headaches, cramps, joint pain)

• Poor sleep and cravings for carbs/sugar

• Digestive issues (bloating, diarrhea, or constipation)

Serotonin and PMS/PMDD

Serotonin Level	Effect on PMS Symptoms	Symptoms
Low Serotonin (Common in PMS/PMDD)	Worsened mood swings, cravings, & fatigue	Depression, anxiety, irritability, fatigue, cravings
High Serotonin (Rare, but possible with IBS-D)	Causes digestive issues & anxiety	Loose stools, bloating, nausea, restlessness
Fluctuating Serotonin	Unstable mood & digestion	Mixed PMS symptoms, alternating diarrhea & constipation

Irritability and serotonin

Serotonin is a key neurotransmitter that plays a crucial role in regulating mood, emotional stability, sleep patterns, and impulse control. When serotonin levels are low or imbalanced, one of the most common emotional symptoms that emerges is irritability.

Serotonin acts as a natural mood stabilizer in the brain. It helps modulate responses to stress and frustration, supporting calmness and emotional resilience. When serotonin is functioning well, people tend to feel more patient, optimistic, and in control of their emotions. However, when serotonin levels drop—whether due to chronic stress, poor diet, hormonal shifts, certain medical conditions, or genetic factors—the brain becomes more reactive, and emotional regulation is weakened. This can result in increased irritability, where even small triggers may provoke anger, frustration, or agitation.

Low serotonin is often linked to mood disorders like depression, anxiety, and PMDD (premenstrual dysphoric disorder)—all of which commonly include irritability as a symptom. It also plays a role in how people cope with overstimulation and discomfort, meaning that irritability may increase in environments where someone feels overwhelmed or exhausted.

Additionally, serotonin helps regulate sleep and appetite, and disruptions in either can worsen mood and irritability, creating a cycle of emotional instability.

We often think of irritability as a personality trait or a response to a bad day. But irritability is often rooted in biological imbalance—especially involving key hormones and neurotransmitters. When the body is under chronic stress, it alters the function of several systems that regulate mood, emotion, and response to stress.

Adrenaline

Adrenaline is released during the "fight or flight" response. It boosts energy and alertness and prepares the body to respond to stress quickly. With chronic stress, adrenaline levels stay elevated, keeping the nervous system in a heightened state of alert. This leads to overreactions, impatience, and low tolerance to daily stressors. Over time, the constant "on edge" feeling drains emotional stability, increasing irritability.

GABA (Gamma-aminobutyric acid)

GABA is the brain’s primary calming neurotransmitter. It helps reduce neuronal excitability, promoting relaxation and mental balance. Low GABA levels mean the brain struggles to slow down or self-regulate. This results in mental overstimulation, impulsive reactions, and heightened emotional responses. A lack of GABA contributes to poor stress adaptation and irritability in even minor situations.

DHEA (Dehydroepiandrosterone)

DHEA is a hormone that supports mood, mental clarity, and stress resilience. It acts as a protective buffer against the negative effects of cortisol. When DHEA is low, emotional resilience drops. This means the brain becomes more vulnerable to emotional highs and lows, making it harder to manage frustration, pressure, or conflict. DHEA also interacts with mood-regulating neurotransmitters like serotonin and dopamine, which influence emotional balance.

Cortisol

Cortisol is the body’s long-term stress hormone. It helps regulate metabolism, inflammation, and emotional stability. Imbalances in cortisol—whether too high (due to stress) or too low (due to adrenal fatigue)—can cause emotional dysregulation. High cortisol intensifies stress reactions, while low cortisol reduces emotional resilience. Both scenarios make irritability more likely.

Glutamate

Glutamate is a major excitatory neurotransmitter involved in activating brain cells and promoting neural communication.

In balanced amounts, it supports healthy mood, focus, and emotional regulation.

Excess glutamate, often triggered by chronic stress, inflammation, or poor sleep, can lead to overactivation of the nervous system.

This overstimulation affects brain areas like the amygdala and prefrontal cortex, which are involved in emotional control and impulse regulation.

When glutamate levels are too high:

• The brain becomes hyper-responsive to stimuli.

• Minor stressors may trigger exaggerated emotional reactions, such as irritability, anger, or agitation.

High glutamate is often observed in conditions characterized by irritability, including:

• Anxiety disorders

• Depression

• ADHD

• PTSD

Impaired glutamate clearance (due to glial cell dysfunction or inflammation) can prolong this irritability loop by keeping the brain in a heightened arousal state.