Brain Chemicals Explained (Brain Chemistry Guide)

In this article, we have looked at the brain and its different units, as well as a summary of what brain chemicals do and how they work to control human behavior. We also provide a guide to the key chemicals found in the brain and provide a summary of what each one does.

The brain is the most complex organ in the human body. It is the core of our intelligence. It’s able to control human behavior, initiate body movement, and help us interpret senses.

But you could be wondering how the brain can do all this? This is where the chemicals in the brain play a vital role and come into play. In this article, we take a look at these chemicals and how they work in the brain to interpret and receive information.

We look at each chemical’s specific functions and purpose and what happens if you produce too much or too little of one chemical.

With around 100,000 chemical reactions that happen in the human brain per second there’s plenty to talk about, so let’s dive right in.

What is the Brain?

Brain Chemicals Explained (Brain Chemistry Guide)

The brain is an organ able to control each process that regulates the human body. It controls memory, touch, motor skills, human emotion, temperature, hunger, and even our breathing. Ultimately, it is the organ that defines us as humans and controls us as we navigate life.

The brain is made up of about 60% fat with the rest being made up of water, protein, salts, and carbohydrates. The brain is not a muscle and it has its blood vessels, nerves, neurons, and glial cells.

So how do these all work together to control human behavior? This all comes down to the chemicals and electrical signals. The brain can send and receive these signals throughout the body and these signals control processes that your brain can interpret.

Messages can be kept in the brain or relayed down the spine, across the body’s network of nerves to different extremities. The central nervous system is then dependent on billions of neurons to do this.

As the brain makes up such an integral part of the human body, scientists have been fascinated by the organ for centuries and the chemicals it can produce.

In recent years, the increase in neurological and behavioral science and the development of modern research techniques have meant these scientists have been able to research the brain and the nervous system in more depth than ever before.

How is the Brain Divided Up?

The brain is divided up into three different units. These units are the forebrain, the midbrain, and the hindbrain. They work together as a team yet all are built for their own purpose.

If we look at the hindbrain first, the hindbrain controls the basic functions of the human body such as heart rate and respiration. It is part of the upper spinal cord, the brain stem, and the cerebellum.

The cerebellum is also known as the little brain and is located at the back of the head. It has two hemispheres and below you’ll find the temporal and occipital lobes and above you’ll find the brain stem. The outer portion of the cerebellum contains multiple neurons and the inner area communicates with the cerebral cortex.

The cerebellum can coordinate voluntary muscle movements and help the body keep posture, improve balance, and equilibrium. An example to use is if you hit a tennis ball, the cerebellum is activated to do this.

Next is the midbrain. The midbrain is the uppermost part of the brainstem and is used to control certain reflex actions. It’s involved in controlling voluntary movements and the control of eye movements.

The midbrain is made up of a range of different structures such as neuron clusters and neuron pathways. These features are what help with hearing and movement. They help calculate human responses and adapt to environmental changes.

The midbrain additionally contains the substantia nigra. This is an area that is affected by Parkinson’s disease and it is rich in dopamine neurons. It’s part of the basal ganglia, which is what helps with general movement and coordination.

The forebrain is the most developed part of the brain and is the largest section. It is mostly made up of the cerebrum and the structures underneath it. The cerebrum is made up of gray matter, also known as the cerebral cortex, and has white matter in its center.

The cerebrum is key to coordinating movement and helps regulate temperature. It also enables human thinking, speech, judgment, emotions, and reasoning. Moreover, the cerebrum relates to vision, touch, hearing, and other core senses of the human body.

The cerebrum is split into two hemispheres that communicate with each other via a tract of nerve fibers that lie at the base of this fissure. However, each hemisphere is used to help with different functions. For example, the left hemisphere will help your form words, yet the right controls reasoning skills.

Signals from the brain to the body and from the body to the brain cross over. This results in the right hemisphere being in control of the left side of the body and the left hemisphere being in control of the right side. This means, when one side of the brain is damaged, the opposite side of the body becomes affected by this.

Although understanding how the brain is mapped can prove difficult, it’s important to note that the forebrain, the midbrain, and the hindbrain make up the three basic units. These units can be broken down but ultimately they are separate sections that have separate functions to control how the brain works.

What are Chemicals in the Brain?

Chemicals in the brain help interpret and receive information. They have their specific functions and purposes and if you lack a certain chemical, this could cause issues. There are around 100,000 chemical reactions that happen in the human brain per second and they help send electrical wave signals to your body.

Most chemicals in the brain are known as neurotransmitters. They help pass and modulate signals between cells and neurons and they are made up of around 10 different molecules and more than 50 neuroactive proteins.

Neurotransmitter molecules are usually enclosed in vesicles, and a synaptic depolarization ends in calcium ion channels opening which releases them. This is called exocytosis and as they are released, they disseminate along the synaptic divide and stick to receptors. They are then reabsorbed and used for recycling.

Neurotransmitters are methods of communication between neurons and can cause a change of neuron cell permeability, so neurons can distribute impulses depending on the neuron and the transmitter.

The noradrenaline system, the serotonin system, the cholinergic system, the dopamine system are the main neurotransmitters you will find in the brain and each system is ultimately responsible for sending signals to the human body so that it can function on a day-to-day basis.

What is the Purpose of Chemicals in the Brain?

The benefits of each chemical in the brain differ dramatically. This is because each chemical has its function and purpose. For example, acetylcholine can send responses from one cell to another cell and helps move skeletal muscles. It also helps control heart muscles and soft muscles and is the key chemical for coordinating movement.

Each chemical in the brain can not only affect movement and your body, but also human emotion. The dopamine system and the serotonin system are two well-known and well-researched chemicals that drastically impact mood, emotion, and body impulses.

In brain chemistry, when a person has too much of one chemical, or too little of one chemical, on a prolonged basis, this can affect human behavior and in particular, can be the culprit of many mental health issues. When a person has too much of one kind of neurotransmitter, it can lead to what is known as ‘bad nerves’.

The relationship between brain chemicals and mental health stems from how they control each emotion.

Some chemicals cause depression, some chemicals can make you happy, and when a chemical imbalance occurs, this can cause emotional distress and disturbances. Though there has been limited research on chemical imbalances, it is believed to be a result of a person’s thoughts and actions.

Furthermore, chemical imbalances may lead to stress and anxiety yet also help the body laugh, cry, love, and experience other human emotions. They are therefore integral to human nature and help humans react appropriately to certain situations.

Ultimately, the brain uses chemicals and neurotransmitters to use cells and neurons to process information and send signals to the body. They are vital to the functioning of your brain and body and facilitate communication between different nerve cells.

What are the Different Chemicals in the Brain?

Brain Chemicals Explained

The brain contains over 100 known neurotransmitters and scientists are continuously trying to find more. However, certain neurotransmitters have been studied in-depth and are key to understanding the brain’s functioning.

In this next section, we are going to take a look at 12 common chemicals in detail. From what they are made up of, to what they control in the human body, to how they help regulate the normal body functioning.


Dopamine is an inhibitory neurotransmitter with benefits to help improve mood and control your motor movements. It’s related to cognitive abilities and can also help improve memory. It can increase mental awareness and improve concentration.

Dopamine is categorized as a catecholamine. Hydroxylation of tyrosine is considered a rate-limiting step in the biosynthesis of catecholamine and this tyrosine hydroxylase enzyme is blocked by catechol.

Dopamine affects emotional response. This means it is the chemical in the brain that helps a person to feel happiness or experience pain. It can also be paired alongside adrenaline and controls the balance in movements.

As dopamine plays a role in controlling movement, if your brain lacks dopamine, it can cause a lack of movement control which sometimes leads to Parkinson’s disease.

Parkinson’s disease is a progressive movement disorder that causes a tremor in one hand, a slowing down of movement, and overall stiffness. Although there is no cure for Parkinson’s disease, there are known treatments.

A lack of dopamine might also result in losing the ability to think properly. This can lead to conditions such as schizophrenia. If a person lacks dopamine in the tegmental area, which contains limbic systems, this might cause the person to develop a paranoid personality.

Moreover, if a person lacks dopamine in the mesocortical pathway from the tegmental to the neocortex, this might result in memory loss.

Generally, however, dopamine helps get a person excited and increases their tendency to talk. Though it allows a person to experience pain, it also allows them to feel pleasure. It helps you strive to achieve things in life and enables you to find things interesting.

As a result of this, an increase in the chemical can make the person feel confident, extremely happy, excited, and on top of the world. However, too much dopamine, used as a recreational drug can cause long-term side effects such as addiction and heart attacks.


Serotonin is a monoamine neurotransmitter, manufactured with the help of an amino acid called tryptophan, that is synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the digestive tract.

It plays a vital role in controlling body temperature and can also stimulate hunger signals and regulate and impact sleep. It can also affect how the cardiovascular system works.

Serotonin also regulates and impacts arousal, motor, cognitive and autonomic functions, emotions, digestion, arousal, and sexual desire. It can impact mood such as how a person becomes angry and how aggressive a person is as well as act as the stimulus to vomit.

Serotonin plays a large part in brain functioning and the genetic variation in the receptor and transporter of the chemical also has the ability to reuptake. If this is disturbed, it will cause the effects of neurologist defect.

Drugs, that affect how serotonin works and how it is formed are used as part of therapy in psychiatric defects. It’s been reported that people with anxiety disorder have an abnormal serotonin transporter and the effects of such modification mean there are higher chances of that person developing depression.

Serotonin however is still labeled as the ‘happy chemical’ as it provides general feelings of positivity and wellbeing. As a result, an increase in serotonin can treat and prevent symptoms of depression. To increase levels of serotonin, it has been proved that exercise can help, along with a balanced diet and the introduction of bright natural lighting.

In a nutshell, serotonin controls body temperature as well as mood swings and anxiety levels. It regulates sleep and most importantly, can help a human maintain general feelings of happiness.


Acetylcholine is the transmitter substance that’s synthesized on the end of presynapse from coenzyme acetic acid and choline which uses an enzyme called choline acetyltransferase.

This substance is then carried to a specific bulb which releases acetylcholine to the synapse crack. It breaks down the acetic acid and choline and helps form the cholinesterase enzyme, which is a bond with the proteoglycan reticulum and fills the Synapse crack.

The bulb is then able to be recycled and choline is carried back to the end of the synapse and reused for synthesizing the new acetylcholine. Acetylcholine is produced by neurons located in the brain and nervous system and is known for its inhibition effects as well as on peripheral parasympathetic nerves such as heart inhibition by the vagus nerve.

Acetylcholine is another excitatory neurotransmitter, which like dopamine, ultimately causes excitation effects. It can enhance a person’s memory and is related to arousal and sexual performance. This is because it is the chemical that controls blood flow to a person’s genitals.


Norepinephrine is produced by neurons located on both the brain stem and the hypothalamus. Neurons located on locus coeruleus that produce the chemical typically send wide nerve fibers inside the brain. This is what regulates daily activities and enhances alertness.

This chemical directly influences bodily functions. It is a naturally occurring hormone that functions as a neurotransmitter located in the nervous system. It is released into the body when a stressful event has occurred and is known for increasing alertness, arousal, and reaction time when responding to a stressful situation.

Norepinephrine is the chemical that helps with daily activities and daily functions. It can improve concentration levels when working or studying and also has an overall effect on your mood. Because of this, if you lack the chemical, you could experience depression, hypotension, and attention deficit hyper disorder, otherwise known as ADHD.


Glutamate is the common excitatory neurotransmitter in the central nervous system. It takes up around half of all the neurons in the brain and plays an important role in normal body functioning. It is also associated with memory activity, learning, and feelings of excitement.

Glutamate is known for being the most important transmitter in the brain for normal brain function. Roughly all of the excitatory neurons in the central nervous system are glutamatergic and it plays a vital role in clinical neurology.

The chemical is a nonessential amino acid and doesn’t cross the blood-brain barrier. It must be synthesized in neurons from local precursors and is released by glial cells. Once it is within presynaptic terminals, it is metabolized to glutamate by the mitochondrial enzyme glutaminase.

An excess of glutamate will kill off neurons in the brain and might kill off many brain cells too. If a person has brain damage or a stroke, this can cause excessive production of the chemical.

Excessive production may also lead to AIS (Lou Gehrig’s disease) and it is believed it can also be responsible for many different diseases in the nervous system. Scientists are now trying to find ways of minimizing the effects of this.


Epinephrine is a hormone found in the brain which plays an important role in reducing short-term stress. It is produced by adrenal glands when the brain picks up on a stressful situation.

When released into the bloodstream, it will help maintain the body’s requirements which a dangerous situation occurs and it does this by releasing extra oxygen and glucose to the brain and muscles.

It can increase a person’s heartbeat, and increase blood sugar levels through improving catabolism of glycogen into glucose in the liver as well as lowering how lipid is formed through fat cells. Furthermore, it is a hormone that controls a person’s metabolic rate, muscle contraction, vasodilation, vasoconstriction, and chemical thermogenesis.

GABA (Gamma-Aminobutyric Acid)

GABA is a naturally occurring amino acid that works as an important neurotransmitter. It is considered an inhibitory transmitter, like serotonin, as it is able to block or inhibit brain signals and decrease activity in the nervous system.

When the chemical attaches itself to a receptor, it can produce a calming effect in your brain when your cells and neurons become overexcited. It is also thought to lower blood pressure, relieve pain, increase the growth of muscle mass, improve sleep, relieve anxiety, burn fat and improve overall mood.

GABA is thought to be one of the most important chemicals in the brain as it has such a vital role in controlling neuron excitability through the nervous system. It therefore also controls how people experience emotions such as fear, anxiety, and stress. The chemical acts to slow or completely block certain nerve signals in the brain, which is what relieves anxiety.

If a person lacks GABA, nerve cells can be activated in a way that exacerbates certain conditions related to anxiety and induces anxiety disorders. Having the right amount helps stabilize this and stabilize a person’s mood.


Aspartate is known as the instigator of neurotransmission inside the brain and nerve muscles. It plays a vital role in preventing fatigue and is a product of urea recycling which involves gluconeogenesis.

Aspartate is a neurotransmitter in the brain that stimulates the N-methyl-D-aspartate (NMDA) receptor yet is not as strong as the stimulation of the chemical, glutamate to the same receptor.


Glycine or aminoethanoic acid is a simple natural amino acid and is the smallest amino acid from the other 20 types of amino acids found in protein. It’s the only amino acid that lacks an optical isomer as the residual group that bonds to the alpha carbon atom are the hydrogen atom and this is what makes the symmetrical structure.

Glycine is also another inhibitory transmitter and is located in the brainstem and the spinal cord. It participates in a range of motor and sensory functions and can help with panic attacks. Glycine is present in the forebrain and has been shown to function as a coagonist at the N-methyl-D-aspartate (NMDA), a subtype of glutamate receptor.

Nitric Oxide

Nitric oxide is a molecule transmitter that is responsible for human behavior and memory activity. It is not stored in the bulb at the end of the presynapse like other molecule transmitters and is instead produced when needed. It will then be diffused out of the presynapse and not released through the bulbs.

The molecule will then be diffused and sent to the postsynaptic neurons. In these neurons, nitric oxide won’t stimulate the potential membrane to increase in size but will alter the intracellular metabolic function which stimulates neuron electability.

Nitric oxide allows the brain blow flow and plays a role in intracellular signaling in neurons from the regulation of neuronal metabolic status to the dendritic spinal growth. It also helps protein function.


Oxytocin is a neurotransmitter that is commonly referred to as another ‘happy’ chemical. It plays a vital role in human social behavior and cognition and is present in reproduction. It is related to maternal functions such as labor, lactation, childbirth, and the initiating of contractions.

When this chemical is released, it causes the person to feel relaxed and warm. It’s another chemical in the brain associated with sexual activity and human orgasms and is therefore heavily present for couples in those first few months of a relationship.

As a result of this, it is a chemical that has overall enhancing effects on any relationship and these include gazing, empathy, fidelity, trust, improved communication, and the processing of bonding cues. It is known as being the driving force behind human attraction.


A neuropeptide is our final brain chemical and is a group of transmitters. There are around 40 different types of peptides that are known to function as neurotransmitters and this list could potentially be longer as a result of the discovery of putative neurotransmitters.

Neuropeptide has been studied as a hormonal substance and was founded on research in endocrinology, biochemistry, and physiology. Neuropeptides are a class of molecules that engage in many different physiological functions.

A neuropeptide is released into the bloodstream by the endocrine gland and leads to the brain tissues. However, it has also been proved that peptides can act as a neurotransmitter and can be synthesized and released by neurons located on the nerve structure.


The brain can be a complex organ and for this reason, it has been researched and studied for centuries. Chemicals in the brain are a vast research area, of which scientists are still trying to navigate. However, to summarise what they are, most chemicals are known as neurotransmitters which brain cells use to communicate and send signals throughout the body.

Certain neurotransmitters are excitatory whilst others are inhibitory. Excitatory transmitters make cells active whereas inhibitory dampen the cell activity.

The noradrenaline system, the serotonin system, the cholinergic system, the dopamine system are the main neurotransmitters you will find in the brain and each system is responsible for sending signals to the human body so that it can function and work together to control human behavior.