How Brain Chemistry Affects Your Mood

Photo by Soheb Zaidi on Unsplash

Mood is often seen as a reflection of what is happening in your life — relationships, stress, work, health. But there is another layer underneath all of that: brain chemistry. The balance (or imbalance) of key neurotransmitters has a powerful influence on how we feel, think, and respond to the world.

When brain chemistry is in balance, emotions tend to feel steady and manageable. When it is off, even small challenges can feel overwhelming. Here is a closer look at some of the key players in mood regulation.

Serotonin

Serotonin is often called the “feel good” chemical because it plays a central role in mood stability and emotional regulation. Low serotonin is linked with depression, rumination, and difficulty managing stress. Healthy serotonin levels support calmness, optimism, and resilience.

Research shows that lifestyle factors such as exposure to sunlight, regular physical activity, and balanced nutrition can naturally boost serotonin production. This is one reason why practices like daily walks, outdoor time, or a diet rich in whole foods often leave people feeling more emotionally grounded.

Dopamine

Dopamine is the neurotransmitter of motivation, reward, and pleasure. It helps drive us toward goals and makes achievements feel satisfying. When dopamine is low, people often feel flat, unmotivated, or unable to enjoy activities. When it is well-regulated, life feels engaging and purposeful.

However, dopamine can also be hijacked by unhealthy habits such as excessive social media use, gambling, or substance misuse. These activities create short bursts of dopamine, but over time they reduce sensitivity, leaving us craving more stimulation without lasting satisfaction.

Norepinephrine (Noradrenaline)

Norepinephrine, also known as noradrenaline, is tied to alertness, focus, and the body’s response to stress. Too much can leave you feeling anxious, restless, or on edge. Too little may cause fatigue, low energy, or a sense of indifference. It helps fine-tune how reactive we are to the world around us.

This chemical is particularly important during times of challenge, when quick thinking and sharp focus are required. However, when the system is constantly overstimulated, norepinephrine can fuel chronic anxiety or burnout, making it difficult to feel calm and at ease.

GABA

GABA (gamma-aminobutyric acid) is the brain’s primary calming chemical. It helps regulate overactivity in the nervous system and promotes relaxation. When GABA is low, people may feel anxious, overstimulated, or unable to switch off. Balanced GABA levels support calm focus and restful sleep.

Mindfulness, deep breathing, and certain relaxation practices have been shown to enhance GABA activity, which is why they are so effective for managing stress. In fact, many anti-anxiety medications work by amplifying the effects of GABA, highlighting just how central it is to emotional balance.

Cortisol

Cortisol is technically a hormone rather than a neurotransmitter, but it is central to mood. It is released by the adrenal glands in response to stress. In small amounts, cortisol helps us wake up, stay alert, and respond to challenges. Chronic high cortisol, however, can lead to anxiety, irritability, and difficulties with sleep. Low cortisol can leave you depleted and fatigued.

Over time, consistently high cortisol can wear down the body, impacting not only mood but also immune function, blood pressure, and memory. Learning to manage stress through rest, boundaries, and supportive relationships is key to keeping cortisol in a healthy range.

Behaviours Affect Brain Chemistry

It is important to remember that brain chemistry is not fixed. Sleep, exercise, nutrition, sunlight, social connection, and stress all shape your neurochemistry. Trauma, genetics, and chronic stress can disrupt this balance, which is why some people are more prone to mood disorders despite otherwise “good” circumstances.

Therapeutic work can help shift long-standing thought patterns that affect mood, but biological supports are sometimes needed too. Antidepressants or mood stabilisers are medical interventions for physiological imbalances and are no different from taking blood pressure medication.

Understanding your mood through a brain-based lens can reduce self-blame. It shifts the story from “What is wrong with me?” to “What is happening in my system, and how can I support it?”