Acetyl-L-Carnitine (ALCAR) Review: Discover the Cognitive Benefits, Side Effects, and Nootropic Stacks

What is Acetyl-L-Carnitine (ALCAR)

Acetyl-L-Carnitine (ALCAR), sometimes referred to as Acetyl Levocarnitine in academic settings, is a nootropic used to increase mental energy, improve focus, boost memory and learning ability, and protect our brains against age-related cognitive decline.

These functions are largely thanks to its ability to boost the health and function of our mitochondria and neurons (brain cells) along with its impact on our cholinergic system.

Chemically this compound is L-Carnitine with an added acetyl group. L-Carnitine is a derivative of lysine, an amino acid. This acetyl group allows this nootropic to easily cross over the blood-brain barrier, a membrane that separates our brain’s blood vessels from the neurons and other parts of our brain.

Our bodies produce their own L-Carnitine and we also synthesize some from the lysine found in animal products. Even though an actual deficiency in carnitine is rare, supplementation has been found to produce a wide variety of benefits for the body and brain.

There are three versions of L-Carnitine that people will supplement with for different purposes:

  1. Acetyl-L-Carnitine (ALCAR): Brain health and function (nootropic benefits)
  2. L-Carnitine L-Tartrate (LCLT): Exercise performance and physical power
  3. Glycine Propionyl L-Carnitine (GPLC): Blood flow and alleviation of intermittent claudication

In animals studies, Acetyl-L-Carnitine has been shown to be the most bioavailable of these carnitine supplements.

What is ALCAR Used For?

Thanks to its chemical structure, Acetyl-L-Carnitine exerts the majority of its effects on brain function and health.

The main benefits of ALCAR include:

  • Increases focus
  • Helps relieve depression
  • Acts as a stimulant, reducing mental fatigue
  • Boosts brain health
  • Promotes memory and learning
  • Improves insulin sensitivity
  • Enhances capillary (blood vessel) health

How Does ALCAR Work?

Choline and Acetylcholine

Many of the memory and learning benefits attributed to ALCAR are believed to be thanks to improved cholinergic function.

In a study on mice fed ALCAR daily, it was found that these mice were more able to learn new tasks when compared to placebo mice. (6) The researchers believe that this was largely thanks to the cholinergic activities of this supplement. They found that synaptic high-affinity choline uptake (HACU), acetylcholine (ACh) synthesis, and ACh release were all increased with supplementation.

ACh is a neurotransmitter critical for learning, memory, focus, arousal, and sleep. It is believed that the rate-limiting step in production of ACh is HACU. By increasing HACU and ACh synthesis and release, users can experience noticeable boost in their cognitive function.

Another animal study found that rats who were given ALCAR daily led to less degeneration in both number and size of cholinergic cells in the basal forebrain. (7)

As we get older, the levels of this crucial neurotransmitter slowly fall. This decline is partly responsible for:

  • Decreased mental energy, or “brain fog”
  • Problems learning new things
  • Difficulty recalling memories
  • Trouble focusing
  • Age-related neurological conditions

Thanks to this natural decline, it is important to find ways to help keep levels of this neurotransmitter high. ALCAR has been shown in studies to help do this.

Supports Brain and Neurotransmitter Metabolism

ALCAR has been shown to increase energy in the brain and also boost neurotransmitter metabolism.

The mitochondria of our cells are known as our cell powerhouses. In essence, the mitochondria are in charge of producing energy for the cells throughout the body.

The amino acid L-Carnitine is important for the metabolism and health of our mitochondria. When these energy producers are functioning well, they contribute to healthy cognitive functions. As we age their function can decrease, leading to age-related cognitive decline.

In a study on mice, long term ALCAR supplementation was found to increase the levels of serotonin in the cortex and noradrenaline in the hippocampus. (15)

Low serotonin levels are linked to depression, and this neurotransmitter is known to play important roles in mood, sleep, memory, appetite, and more.

Noradrenaline, also known as norepinephrine, is critical for our ability to focus, memory, creativity, and alertness.

Indirect Antioxidant and Neuronal Protection

ALCAR has shown effectiveness in boosting antioxidant activity in the brain, protecting brain cells, and preventing mitochondrial damage.

In one study this compound was found to prolong the activities of certain antioxidant enzymes intrinsic to the human brain, including Superoxide Dismutase. (13) This is thought to be one of the ways by which it prevents mitochondrial damage.

The Cognitive Benefits of ALCAR as a Nootropic Supplement


In animal studies Acetyl-L-Carnitine has been found to both improve learning in older mice and mitigate age-related cognitive decline when fed to young mice daily at low doses (about 10 mg/kg daily for humans). (6,7)

In the elderly population, this nootropic has been found to improve memory in those with memory impairments and Alzheimer’s disease. (8,9,11)


In a double-blind randomized study Acetyl-L-Carnitine was compared to Amisulpride in effectiveness of treating dysthymia, which is a subtle yet chronic depression. (5) In comparison to Amisulpride, a common prescription for dysthymia, ALCAR was found to be just as effective at alleviating symptoms all while being better tolerated, with a greater safety profile.

A meta analysis found that preliminary controlled trials of ALCAR supports the antidepressant effects of this compound, particularly in the elderly population. (12)


Two studies in children have found improvement in ADHD symptoms with treatment of carnitine. (1,2)

In one of the studies, boys with both ADHD and fragile X syndrome were treated with either ALCAR or placebo for one full year. In comparison the placebo group, ALCAR significantly improved both social behavior and hyperactivity. (2)

In another study on adults with chronic fatigue syndrome, daily supplementation with 2 g/day ALCAR led to improvements not only in mental fatigue, but also in attention and concentration. (4)


Chronic fatigue is becoming increasingly common in Western countries. As we push ourselves to mental and physical extremes daily, fatigue is all too common. Chronic fatigue is especially frequent in the elderly population.

Multiple studies have found that supplementation with this compound can help reduce chronic fatigue. (3,4)

One study on elderly patients age 71-88 with chronic fatigue found that daily supplementation with ALCAR led to improved mental and physical fatigue when compared to placebo. (3) Cognitive status and physical ability were also positively impacted.

Another study looked at the impact of supplementation for six months with 2 g/day ALCAR plus 2 g/day Propionyl-L-Carnitine at fatigue, sexual dysfunction, and fatigue that is associated with male aging. (14) This study found benefits for not only fatigue, but depression and sexual dysfunction as well.


Every day as we get older, the function of our brains tends to decline. This can be thanks to consumption of alcohol, pollution, or even simply the aging process. Much of the damage that occurs to our brains as we grow older is thanks to damage from reactive oxygen species.

Studies have found that this nootropic protects neurons from oxidative damage, and can even help the brain flush out toxins. It has also been shown to restore synaptic transmission, also known as neurotransmission, from alcohol consumption. (16)

Age-Related Cognitive Decline

Over 20% of adults 60 and older suffer from a mental or neurological disorder, with this number continuing to increase into older age. (11)

Many studies have confirmed that supplementing with ALCAR may lead to improvements in the decline of cognitive abilities that come with age.

In one study on those over 65 with mild mental impairment, it was found that 2 grams of this nootropic daily for three months led to improvements in memory, attention, verbal fluency, and behavior. (10)

Alzheimer’s Disease

Multiple human studies have found supplementation with this compound to lead to improvements in symptoms associated with Alzheimer’s disease and dementia of the Alzheimer’s type. (8,9)

In one 24 week double-blind, placebo-controlled study, both short-term memory and reaction time showed a trend towards improvement in the treatment group compared with placebo, although the differences between the groups did not reach statistical significance. (8)

In another, longer study of one year, patients with Alzheimer’s disease were either treated with placebo or ALCAR. (9) While both groups showed deterioration over the year, this deterioration was slower for 13 of 14 measured outcomes for the treatment group. These differences did reach statistical significance for focus, memory, critical abilities, and logical intelligence.

Side Effects

This supplement is very well tolerated and considered safe when taken within the standard dosage.

The most common side effects are nausea and head pain. It is not uncommon for users to report headaches, and in rare cases, migraines, when taking this supplement. Other side effects include:

  • Trouble sleeping
  • Digestive upset
  • Diarrhea
  • High blood pressure

This supplement has been linked to psychosis in people with bipolar disorder and higher triglycerides and lower blood sugar in those with diabetes. There are some other conditions and medications that can be affected by using this supplement. Click here for a full list of side effects on WebMD.

Recommended Nootropic Dosage

ALCAR is generally taken daily in quantities between 250 and 2,000 mg/day, with or without food. If you experience any digestive upset or pain when taking without food, you will want to take with breakfast and/or lunch.

The best time to take this supplement is early in the day. Avoid taking it late in the day as this can lead to trouble sleeping.

If you are a healthy adult looking to add this supplement to your nootropic stack for its memory, brain function, and energy effects, dosage normally starts at 500 mg/day.

Some users report the benefits all day long when taken in the morning time, while others prefer the feeling when they split their doses. With a half-life of around 4.2 hours for 500 mg, you may find heightened benefits splitting into two. This half-life is highly variable, so experiment to see what is best for you.

If you will be using this drug for certain conditions, you may need more. For example, dosage for chronic fatigue is generally around 2 grams daily

Nootropic Stacks

Acetyl-L-Carnitine and Choline Stack

Taking choline with this supplement is a good idea when it comes to reducing side effects and boosting your production of ACh, and thus your memory, learning, and cognitive benefits.

ALCAR is known to boost the production of high affinity choline uptake, and this choline is in turn used to synthesize the ACh. Without sufficient choline stores in your body, this nootropic could lose its effectiveness and cause headaches and fatigue.

To get the most out of your choline and Acetyl-L-Carnitine stack, we recommend either Alpha GPC choline or CDP-Choline (also known as Citicoline), two highly bioavailable choline supplements that are able to cross over the blood-brain barrier efficiently.

Try one of the below daily stacks:

  1. 500 mg ALCAR + 300 mg Alpha GPC or
  2. 500 mg ALCAR + 250 mg CDP Choline

Acetyl-L-Carnitine and Piracetam Stack

This supplement is especially powerful in a nootropic stack with members of the racetam family. The effects of both nootropics are reported to be amplified when combined.

While the most common addition to a racetam stack is a highly bioavailable form of choline (such as Alpha GPC and CDP-Choline), ALCAR has demonstrated efficiency at boosting the benefits of the racetams through cholinergic function outside of providing a choline source.

But why do these two nootropics stack so well together?

Racetams are known to increase the levels of ACh, often through increased synthesis.

Just as choline is needed for the synthesis of ACh, so is acetate. Acetate formed in your body after taking ALCAR can combine with choline to produce ACh.

Combine this with the ability of this nootropic to increase choline uptake and ACh synthesis in the body, and you have a perfect drug to stack with racetams.

Piracetam is one of the oldest and most popular nootropics and is a member of the racetam family. Its benefits range from improved learning and memory to stimulation and protection against age-related cognitive decline. As you may have noticed, these benefits are very similar to those experienced when supplementing with ALCAR.

If you do pair Piracetam and ALCAR, it is also a good idea to add in a supplemental choline source. One suggested daily stack would be:

  • 500 mg ALCAR
  • 2-4 g Piracetam
  • 300 mg Alpha GPC

User Reviews

The majority of studies on this supplement have been aimed at populations with existing conditions, such as the elderly. Very little research has been conducted when it comes to whether or not these effects carry over to a healthier, younger population.

User reviews, however, support the nootropic benefits of improved attention and focus, improved learning and memory, and increased mental and physical energy.

“Love it. Fuels brain cell mitochondria. Frankly – lots of mental energy, small improvements in verbal fluency. Colors are a bit more interesting.”  Reddit user review ALCAR

“I’m a medical student studying for my board exams. I use this alongside a racetam stack with citicoline and bacopa. While the bacopa and racetams are more cognitive enhancers, ND’s ALCAR just stops me from ever feeling mentally fatigued; I remain sharp the entire day as I study all day, every day.” Nootropics Depot review of ALCAR 500 mg capsules

Best ALCAR Supplement

ALCAR is one of the few nootropic supplements that is readily available at drug stores across the United States, however it is still better to purchase this supplement online. Online you will find better prices and user reviews specific to the supplement you purchase.

This supplement comes in both powder and capsule form that you can find on Amazon or reputable online nootropic vendors. We recommend Pure Nootropics or Nootropics Depot for consistently high-quality nootropics at competitive prices.


  1. Efficacy of carnitine in the treatment of children with attention-deficit hyperactive disorder

  1. A double-blind, parallel, multicenter comparison of L-acetylcarnitine with placebo on the attention deficit hyperactivity disorder in fragile X syndrome boys

  1. Acetyl L-Carnitine treatment in elderly patients with fatigue

  1. Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome

  1. A double-blind, randomised, controlled clinical trial of Acetyl-L-Carnitine vs. amisulpride in the treatment of dysthymia

  1. Enhancement of learning capacity and cholinergic synaptic function by carnitine in aging rats

  1. Behaviour and degenerative changes in the basal forebrain systems of aged rats (12 months old) after Levo-Acetyl-Carnitine treatments

  1. Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer’s disease

  1. Long-term acetyl-l-carnitine treatment for Alzheimer’s disease

  1. Mental impairment in aging: selection of patients, methods of evaluation and therapeutic possibilities of acetyl-L-carnitine

  1. Mental health of older adults

  1. Acetyl-L-carnitine and alpha-lipoic acid: possible neurotherapeutic agents for mood disorders?

  1. Stabilization of superoxide dismutase by acetyl-L-carnitine in human brain endothelium during alcohol exposure: novel protective approach

  1. Carnitine versus androgen administration in the treatment of sexyal dysfunction, depressed mood, and fatigue associated with male aging.

  1. Chronic acetyl-L-carnitine alters brain energy metabolism and increases noradrenaline and serotonin content in health mice

  1. Acetyl-L-carnitine protects neuronal function from alcohol-induced oxidative damage in the brain