All About Acetylcholine: Neurotransmitter for Memory and Focus

Last updated August 21, 2024.
Edited and medically reviewed by Patrick Alban, DC. Written by Deane Alban.

A low level of acetylcholine has a uniquely negative impact on memory and focus. Learn the three most effective ways you can increase acetylcholine.

Neurotransmitters are generally categorized as either excitatory or inhibitory, but acetylcholine doesn’t fall neatly into either camp.

It functions differently depending on its location and the type of receptors available. 

Acetylcholine doesn’t occur just in the brain and the nervous system, it’s distributed throughout the body.

In muscles, for example, it has an excitatory effect; but in the heart, it’s inhibitory.

What Does Acetylcholine Do?

Acetylcholine is found throughout the body, performing a wide array of functions.

In the brain, acetylcholine functions as both a neurotransmitter and as a neuromodulator, a substance that modulates the action of neurotransmitters, up or down, as needed. 

As a neurotransmitter, it helps us learn, focus, and stay mentally alert. 

It is also involved in functions as diverse as wakefulness, REM sleep, digestion, muscle contractions, attentiveness, anger, aggression, sexuality, and thirst. 

Acetylcholine enhances brain plasticity, the brain’s capacity to stay mentally flexible.

It is the main neurotransmitter of the parasympathetic nervous system which controls automatic functions such as digestion, respiration, and heart rate. 

Any time the fight-or-flight response has been triggered, acetylcholine helps bring the body back into homeostasis by dilating blood vessels and slowing heart rate.

It also causes skeletal muscles and muscles in the intestines and lungs to contract.

It triggers the secretion of sweat, saliva, and tears in their corresponding glands.

Acetylcholine levels tend to decline with age and the kind of memory loss considered to be part of normal, age-related cognitive decline is often caused by this drop.

Acetylcholine is essential for the conversion of short-term memories into long-term ones.

This occurs in the hippocampus, the part of the brain that is considered the brain’s memory center.

The hippocampus is typically the first area of the brain to degenerate in dementia and Alzheimer’s.

The first signs of low acetylcholine are declines in visual memory, verbal memory, processing speed, and spatial orientation.

When visual memory starts to decline, you’ll find it harder to remember what you just read, to form images in your mind, to recall faces, or to remember where things are.

When verbal memory starts to go, you’ll more often forget words or lose your train of thought in the middle of a conversation.

If you find yourself driving under the speed limit or getting lost more easily, these may be signs that your acetylcholine level is low.

This is why most drugs for treating Alzheimer’s, such as Aricept, Exelon, and Razadyne, work by blocking the breakdown of acetylcholine to help keep levels up. 

While these drugs can’t cure or stop the progression of Alzheimer’s, they can temporarily slow it down.

Causes of Acetylcholine Deficiency

There are a few medical reasons why you might have low levels of acetylcholine.

It is possible to have antibodies against acetylcholine receptors as in the case of myasthenia gravis. 

There’s evidence that similar autoimmunity to acetylcholine receptors sometimes occurs in certain psychiatric disorders and chronic fatigue syndrome.

Insulin resistance and diabetes can interfere with acetylcholine synthesis. 

But the two most common causes of acetylcholine deficiency, by far, are diet and medications, factors that are largely under our control.

How Low-Fat Diets Cause Acetylcholine Deficiency

Low-fat and vegetarian diets are so popular that they’re almost considered mainstream.

But these diets put the brain at risk and, in this scenario, acetylcholine is a pivotal player.

Here’s why …

Acetylcholine is synthesized mainly from choline, a nutrient related to the vitamin B complex. 

Acetylcholine production is limited by the amount of available choline, but 90% of us don’t get adequate choline from our diets. 

The best food sources of choline are egg yolks and organ meats, but all fatty animal foods contain some of it. 

There are a few plant sources of choline, but it’s extremely hard to get enough from plants to meet the daily Adequate Intake (AI) requirement of choline — 425 mg for women and 550 mg for men.

Drugs That Lower Acetylcholine Levels

The second major cause of acetylcholine deficiency is the use of drugs called anticholinergics which block the action of acetylcholine.

It’s easy to remember which drugs affect acetylcholine because their common names start with “ant” or “anti” such as antacids, antibiotics, antihistamines, antihypertensives, and antidepressants. 

While most anticholinergics are prescription drugs, there are also a number of common over-the-counter (OTC) remedies included in this group, such as Benadryl (antihistamine) and Pepcid AC (antacid).

Seniors’ brains are at particular risk due to the use of anticholinergic drugs as this significantly increases the risk of dementia. 

There’s even evidence that people who eat eggs have a lower risk of heart disease than those who don’t eat eggs. 

A large long-term study conducted by researchers from the Harvard T.H. Chan School of Public Health followed the dietary habits of over 200,000 people for more than 30 years.

Researchers concluded that there is no link between moderate egg consumption and heart disease. 

The Best Acetylcholine Supplements

Another way to increase acetylcholine is with appropriate supplements.

Alpha-GPC and citicoline provide the brain with choline that readily turns into acetylcholine.

Taking one of these supplements is critical if you don’t eat eggs, organ meats, or other fatty meats.

There are several herbal brain supplements that work, in part, by increasing acetylcholine, including bacopa (Bacopa monnieri), gotu kola (Centella asiatica), and American ginseng (Panax quinquefolius). 

This means that they do not become less responsive to drugs or supplements over time, so you do not need to keep taking more to achieve the same effects.

In fact, the opposite occurs.

Stimulating acetylcholine receptors makes them more responsive so that, eventually, you may find that you need less acetylcholine supplementation to get the same benefits.

Another benefit of acetylcholine-boosting supplements is that you can take them on an as-needed basis, much like drinking coffee when you need a mental energy boost.

While working with patients and experimenting on himself, Dr. Kharrazian (see above) discovered that you can safely add or increase acetylcholine supplements as needed during periods of intense focus and concentration, such as when taking exams or working on a mentally taxing project.

And finally, when you take supplements that increase acetylcholine activity, it’s not unusual to feel a boost in mental energy almost immediately, usually within a half hour.

Causes and Symptoms of Excess Acetylcholine

Most of the time, a neurotransmitter imbalance is a case of too little, rather than too much.

But it is possible to have an excess of acetylcholine, especially if you are taking active measures to increase your acetylcholine levels.

When you start taking any substance that is known to increase acetylcholine, begin with a low dosage and increase the amount gradually.

Too much acetylcholine can cause confusion, headaches, salivation, muscle cramps, nausea, and urinary frequency. 

Some of these symptoms make sense when you consider that acetylcholine is in charge of skeletal muscle contractions and gastrointestinal muscles.