What is Acetylcholine? Functions and Effects In The Brain

Nootropics often focus on boosting acetylcholine as a catalyst for benefits, but many people don't know what it is.

What is Acetylcholine? Functions and Effects In The Brain

Acetylcholine plays an essential role in several functions around the body, and it influences mood, sleep, cognition, and more.

Not only that, but you may not have as much acetylcholine as you used to since it can decrease with age.

Despite the many benefits to the human body and brain, even experienced nootropic users cannot even explain why it is so important.

But knowing more about acetylcholine can help you learn signs of deficiency, natural methods to increase the concentration, and the multitude of effects.


What is Acetylcholine (ACh)?

Acetylcholine was first isolated in 1914, making it the first neurotransmitter discovered. It acts as a neurotransmitter, a chemical messenger that plays a vital role in the brain.

Acetylcholine is the chief neurotransmitter in the parasympathetic nervous system and functions in both the central nervous system, CNS, and the peripheral nervous system, PNS (1).

While acetylcholine levels work for many functions, it is most commonly associated with memory, cognition, and sleep.

Furthermore, an imbalance in levels of acetylcholine can contribute to different neurological conditions. For example, low acetylcholine levels are often found in people with Alzheimer’s disease, myasthenia gravis, and Parkinson’s disease.

Acetylcholine Synthesis

Acetylcholine, or ACh, acts as a non-monoamine subtype, so it does not have an amino group connected to an aromatic ring by a carbon chain. Instead, ACh synthesis involves two chemical groups: choline and acetyl coenzyme A (AcCoA) from glucose.

Neuroscience suggests that choline, the metabolic precursor to acetylcholine, requires the enzyme choline acetyltransferase to convert into acetylcholine. Thus, acetylcholine offers both excitatory and inhibitory effects.

Acetylcholine is produced in the autonomic nervous system by cholinergic neurons within the cytoplasm of nerve terminals. This occurs in the presynaptic cell when cholinergic synapses diffuse the acetylcholine across the synaptic cleft.

After diffusion, the vesicular acetylcholine transporter will move the acetylcholine into synaptic vesicles, binding with different postsynaptic receptors.

Acetylcholine Receptors

There are two types of cholinergic receptors that work in different ways in the brain (2). The two receptors are the nicotinic acetylcholine receptors and the muscarinic acetylcholine receptors.

Nicotinic acetylcholine receptor signaling in the brain helps to activate skeletal muscles. This is why the action at nicotinic receptors makes acetylcholine so important for neuromuscular junction and smooth muscle function.

The poison curare is known for blocking these receptors, which causes skeletal muscle problems, even paralysis of muscle actions.

Cholinergic muscarinic receptors are located all around the body, from the heart and gut to glands and the brain.

Abnormal activity regarding these receptors may contribute to addiction, schizophrenia, and Huntington’s disease.

What Are The Acetylcholine Functions?

Since acetylcholine influences many functions in various ways, it plays an important role in the body and brain.

Central Nervous System

Acetylcholine has an essential function within the CNS because it acts as both a neurotransmitter and a neuromodulator. As a result, it can boost motivation and increase feelings of fulfillment and pleasure.

Acetylcholine also has an activity that relates to arousal. This interaction with motivation also refers to action and reaction.

The way that acetylcholine works in the nervous system allows it to connect thoughts with actions. This means that it turns thinking patterns into movement.

These effects make acetylcholine a necessary compound for the fight-or-flight response. So, these actions are important for productivity, task completion, and recognition and can help with physical and mental health.

Not only that, but acetylcholine inactivation, or if it is blocked, there can be severe side effects and problems within the CNS. Conversely, levels of acetylcholine that are too high can also lead to severe CNS problems.

Learning and Memory

Acetylcholine is also crucial for memory and learning. For example, some of the memory loss in people with Alzheimer’s disease actually correlates with levels of acetylcholine, which shows a direct connection.

Some medications are used to treat Alzheimer’s disease by influencing acetylcholine activity. There is also evidence that acetylcholine may be helpful for memory with otherwise healthy adults (3).

Acetylcholine affects synapses that are crucial for making lasting connections to experiences. This allows us to retain brain plasticity to continue storing new information and confidently recall memories with ease when acetylcholine is available.

Recollection is a critical facet of learning and should not be an overlooked benefit of adequate acetylcholine concentrations.

Moreover, when we improve learning and memory, we also tend to have vastly improved cognitive function in other areas simultaneously.

Our cognitive and work performance relies heavily on properly storing and retrieving information, and acetylcholine is necessary for those processes.


The neurotransmitter acetylcholine regulates natural sleep cycles, the balance of sleep, and mental energy. Acetylcholine neurons work alongside other neurotransmitters to promote both quality sleep and wakefulness.

Research shows that acetylcholine neurons increase during waking and are decreased and suppressed during sleep, particularly during slow-wave sleep (4).

For people who have low levels of acetylcholine, increasing the amount can have a stimulating effect that is less likely to cause difficulty sleeping than other stimulant drugs or medications.

In addition, the sleep that acetylcholine promotes is related to cognitive benefits, thereby increasing the effectiveness of supplements containing acetylcholine as a nootropic.

Finally, while acetylcholine is generally found in lower amounts during sleep, there is an uptick during the most important type of sleep, REM. This can help you process information and memories from the day before without interrupting your sleep cycle or causing drowsiness the next day.

So, while acetylcholine may not do much for those who have insomnia, it can surely keep you on a regular sleeping schedule better than other alternatives.

Attention and Alertness

One of the most sought-after effects of acetylcholine is the boost to concentration, promoting alertness and mental energy (5).

Studies show that higher involvement of acetylcholine is found in individuals who can sustain attention and concentrate for a prolonged period.

Therefore, researchers believe that the correlation is not causal, with acetylcholine playing a significant role in stimulating focus and attention span.

In addition, this concentration related to higher amounts of acetylcholine also offers a mechanism that can help limit distraction. Not only does it allow us to focus for longer, but it allows us to ignore potential distractions better than people with lower acetylcholine levels.

While most of this evidence is found in animals and people with health problems that affect attention, many experts believe these effects can also benefit healthy humans.

When acetylcholine is produced and released, it can also help us fight through feelings of weakness.

While the reason for this is not fully understood, it may be caused by the same signal that is linked with attention. When we are paying attention without distraction, we are less likely to feel fatigued.


Human peripheral nervous systems require acetylcholine to excite the activation of muscle function properly. Systems work by using acetylcholine in smooth muscles, essential for muscle contraction (6).

So, when something does block acetylcholine, it can lead to muscle weakness and even paralysis in some cases.

When the brain sends a signal through nerve fibers and motor neurons to neuromuscular junctions, the signal must get transferred correctly to cause the muscles to react accurately.

This process requires ample amounts of the neurotransmitter acetylcholine. Otherwise, the neurotransmission may not trigger the involved muscle.

Finally, there is speculation that acetylcholine may also spur involuntary movements as part of the fight-or-flight response. While there are other factors involved, acetylcholine is necessary for the reaction from thought to smooth muscles.

Blood Pressure

Acetylcholine is also essential for many processes involving the heart. For example, it helps you regulate heart rate, keeps a steady heartbeat in high-stress and low-stress situations.

It also allows the muscles around the heart to contract and adequately maintains healthy blood flow.

There is some evidence that acetylcholine may also encourage the relaxation of blood vessels. In addition, it may help to improve blood flow throughout the body (7).

This can have several benefits, like better circulation, improved oxygen and nutrient supply, and the prevention of heart disease.

Since acetylcholine and other neurotransmitters may help the health of your heart and blood vessels, and consequently it can supply the brain with more nutrients.

In turn, this could offer some neuroprotection. The brain requires oxygen, nutrients to control nerve impulses, and synapse completion related to cognition and overall health.

Mental Disorders

Mental disorders like Alzheimer’s and schizophrenia correlate with lower amounts of acetylcholine. In addition, normal aging can cause reduced amounts of acetylcholine.

Therefore, some scientists believe that good acetylcholine levels could help prevent or slow memory loss related to age-related decline.

Some people even report that their mood improves after regular supplementation with dietary choline and other options. When acetylcholine is released, it can impact motivation and energy enough to boost mood and outlook potentially.

While these benefits are typically subtle, they work alongside the other effects for an overall healthy feeling.

Finally, mental health is closely related to gut health, and acetylcholine activity in the parasympathetic systems aids in digestion and other gastrointestinal functions.

With better gut health comes better mental health. While this may not be an effect that causes people to pursue choline support, it is an excellent secondary effect nonetheless.


One of the lesser-known benefits of healthy acetylcholine amounts comes with the influence on inflammation. Within the cholinergic system, there is a pathway called the cholinergic anti-inflammatory pathway (8).

The cholinergic activity within this pathway is thought to slow the immune system response and protect against damage that it can cause within essential organ systems and tissues.

When acetylcholine levels are normal and healthy, it can reduce inflammation by increasing pro-inflammatory cytokines. Since inflammation is related to various illnesses, including heart disease, this is a benefit that can do a lot for your body.

Acetylcholine may also influence immune cells and nerve impulses. When acetylcholine activates these cells, there is less inflammation.

However, acetylcholine also regulates the immune response and does not decrease inflammation if necessary to ward off infection or illness.

What Affects Acetylcholine Levels?

There is no scientifically proven way to increase levels of acetylcholine, but there is some evidence showing that consuming choline can help. Choline is found in many nootropics and dietary supplements, but it is also a nutrient in some foods.

Some people get a sufficient amount of choline from their diet to produce enough acetylcholine. But most people do not receive the recommended amount of choline from their diet alone.

A higher choline intake via supplementation of compound Alpha-GPC or Cytidine Diphosphate-choline, and even food, can prevent age-related cognitive decline and boost cognition function (9).

Foods that contain choline include meat, fish, eggs, beans, whole grains, dairy products, nuts, and seeds. In addition, cruciferous vegetables like broccoli and cabbage also contain high amounts of choline.

What Are The Risks of Acetylcholine Deficiency?

While acetylcholine deficiency correlates with Alzheimer’s disease, Parkinson’s, and myasthenia gravis, it can also cause many other symptoms.

Too little acetylcholine can contribute to constipation and other stomach problems, including gastroparesis. Other physical symptoms include dry mouth, dry eyes, increased heart rate, orthostatic hypotension, low muscle tone, and chronic inflammation.

Besides these physiological effects, acetylcholine deficiency can also cause mental symptoms, including memory problems, loss of focus, depression, and mood swings.

If you believe you might have acetylcholine deficiency, then it is best to speak with a doctor. However, as far as treatment goes, there are medicine substances that can stimulate the production of acetylcholine.

Also, many people look for how to increase acetylcholine, and there are many natural methods available. One of them is to take adequate vitamins and supplements to increase acetylcholine concentration.

What Happens If You Have Too Much Acetylcholine?

You don’t want to have too little acetylcholine. Still, you do not want to have exceeded either since too much acetylcholine can cause a release of toxins by flooding the sympathetic nervous system and receptors.

This can cause unpleasant side effects like low blood pressure, confusion, excessive sweating, fishy odor, diarrhea, nausea, and vomiting.

In addition, too much acetylcholine in the neuromuscular junctions and synapses can also cause increased salivation, lacrimation, blurry vision, muscular weakness, and muscular fasciculation.

Too much may even be tied to worsened depression and anxiety. Severe symptoms of too much acetylcholine include liver damage and paralysis.


Acetylcholine is necessary for normal bodily function and brain function. It can also interact with other neurotransmitters to boost mood and support reduced stress.

Consequently, acetylcholine uptake can boost cognition and even contribute to better memory, sleep, and movement.

While acetylcholine has an enormous influence on how we feel, the formation of thoughts and movements, many people do not get enough for proper activation and function.

Because of this, many people seek treatment options from natural sources to supplements and prescription medicine.

While there are many factors involved in releasing sufficient acetylcholine, not having enough or having too much can interfere with daily life and well-being.

Therefore, it is vital to manage proper levels of acetylcholine and other neurotransmitters to enhance physical and mental performance.