Acetyl-L-Carnitine (ALCAR)

David Tomen
David Tomen
Jill Corleone, RD
Fact Checked:
Jill Corleone, RD
10 minute read
Acetyl-L-Carnitine may reverse age-related cognitive decline, boost energy, and improve memory.

Key Takeaways

  1. Acetyl-L-Carnitine (ALCAR) is a synthesized version of L-Carnitine that enhances energy production, supports fat burning, and improves cognitive function.
  2. ALCAR facilitates fatty acid transport to mitochondria, boosts acetylcholine formation, and exhibits antioxidant properties.
  3. ALCAR benefits brain health by supporting mitochondrial function, protecting brain cells, and improving cerebral blood circulation.
  4. It has potential therapeutic effects on conditions such as Alzheimer’s, dementia, Parkinson’s, depression, and mild cognitive impairment.
  5. ALCAR supplementation dosage recommendation is 500 – 1,500 mg per day depending on the desired goal.


Acetyl-L-Carnitine (ALCAR, ALC or LAC) is a synthesized version of L-Carnitine. Which is a derivative of the amino acids lysine and methionine.

ALCAR is more bioavailable than L-Carnitine. It easily crosses the blood-brain barrier. And delivers L-Carnitine across cell membranes and into your brain (which L-Carnitine would not be able to cross on its own).

L-Carnitine is naturally made in your liver and kidneys. And then transported to other tissues including your brain and heart.

ALCAR helps:

Acetyl-L-Carnitine (ALCAR) Overview

L-Carnitine is an amino acid that’s synthesized in your body. You also get it from red meat and dairy.

High quality Acetyl L-Carnitine is found naturally in grass-fed beef and mutton.L-Carnitine is considered a “conditionally essential” nutrient because when your body uses it faster than it can produce it, you need supplemental L-Carnitine either from food or a supplement.

L-Carnitine is used throughout your body. Here we’re talking about the Acetyl-L-Carnitine form of L-Carnitine because of its affects on brain health and chemistry.

L-Carnitine vs. Acetyl-L-Carnitine: What’s the Difference?

L-Carnitine and Acetyl-L-Carnitine are often referred to as Carnitine. But each are structurally different, and each has its advantages.

L-Carnitine: Helps produce energy within the mitochondria of your cells, but is not capable of crossing the blood-brain barrier. Supplemental L-Carnitine is difficult for your body to absorb; only 18% of it reaches your bloodstream.

L Carnitine supplements are favored by athletes and dieters who want Carnitine’s fat-metabolizing benefits. But are not seeking any brain benefits.

L-Carnitine chemical structure

Acetyl-L-Carnitine: Is easier to absorb and used by your body than L-Carnitine. In one animal study, who were given 2 grams of ALCAR daily for 50 days, ALCAR boosted blood levels of ALCAR by 43%.[i]

Acetyl-L-Carnitine chemical structure


ALCAR does everything that L-Carnitine does, but by adding an acetyl group, it but can also cross the blood-brain barrier. In another animal study, researchers found that ALCAR supports mitochondrial function which then protects brain cells from oxidative stress, while L-Carnitine does not.[ii]

How does Acetyl-L-Carnitine Work in the Brain?

Acetyl-L-Carnitine boosts brain health and function in several ways. But two in particular stand out.

  1. ALCAR boosts acetylcholine, a neurotransmitter tied to memory and overall brain function. Acetyl-L-Carnitine is a precursor to acetylcholine in the presence of Coenzyme-A. Test tube studies shows that ALCAR donates a “methyl group” to help make acetylcholine.[iii]

Alzheimer’s-diseased brains show a 25% to 40% reduction in carnitine acetyltransferase, an enzyme that works with L-Carnitine & Acetyl-L-Carnitine.

This enzyme decline led researchers to link low ALCAR with low acetylcholine, and Alzheimer’s onset. They went on to suggest that the therapeutic properties of ALCAR supplementation is a viable therapy for brain regeneration.[iv]

  1. ALCAR promotes brain energy metabolism by supporting your brain cell’s mitochondria in creating ATP which is your main source of cellular energy.[v]

ALCAR works as a shuttle transport for fatty acids through cell membranes into mitochondria to assist with adenosine triphosphate (ATP) synthesis.[vi]

ALCAR is essential for fatty acid oxidation:

  • ALCAR shuttles fatty acids into mitochondria, for the creation of ATP.
  • ALCAR then shuttles fatty acids out of mitochondria, and flushes out tox ic byproducts.

ALCAR helps maintain mitochondrial function in nearly every cell of your body and brain.
ALCAR helps maintain mitochondrial function in nearly every cell of your body. Your brain consumes at least 20% of your body’s energy. And generates a lot of toxic byproducts as well as different chronic intermittent stressors. . So ALCAR supplementation is particularly important for a healthy brain.

How things go bad

As we get older, our brain chemistry and energy metabolism changes.[vii]

↓ Nerve growth factor in the brain declines

↓ Acetyl-L-Carnitine levels decline

↓ Acetylcholine levels decline

↓ Mitochondria loses efficiency

All of these age-related changes are contributing factors to cognitive impairment and the neurodegenerative diseases of aging, including Alzheimer’s and dementia.

ALCAR Nootropic benefits

Animal research conducted at the Linus Pauling Institute at Oregon State University shows that Acetyl-L-Carnitine will:[viii]

  • Restore efficient mitochondrial energy production
  • Replenish age-related changes to mitochondrial structure
  • Replenish ALCAR and acetylcholine levels in the brain and body

One of the most potent Acetyl-L-Carnitine benefits is that it has the ability to boost acetylcholine and rejuvenate brain cells (including mitochondria). This has been proven to benefit those with age-related brain diseases like Alzheimer’s and major depressive symptoms.[ix]

And one animal study conducted in New Delhi showed that Acetyl L-Carnitine reduces lipofuscin in the cerebral cortex, hippocampus, striatum and thalamus.

How does Acetyl-L-Carnitine feel?

You may not feel ALCAR… unless you’re elderly, have low energy levels, or have Erectile Dysfunction. Within those specific groups, users of Acetyl-L-Carnitine report it helps with memory, mental fatigue, mood, mental performance and the ability to get and maintain an erection.

How does ALCAR make you feel?ALCAR’s brain support and its ability to support the mitochondria in your brain cells should boost cognition in all age and gender groups.

As a nootropic, ALCAR user reviews report a boost in energy and quicker thinking.

ALCAR Clinical Research

In one study, researchers showed that ALCAR may have beneficial effects for depression and dementia in the aging brain.[x]

Another study out of Italy; researchers showed that Acetyl-L-Carnitine stimulated the growth of new neurites. More of these minute projections from nerve cell bodies meant increased signaling between cells throughout the central nervous system (brain and spinal cord).[xi]

And a study conducted at the Mount Sinai School of Medicine in New York found that ALCAR has potential in treating the symptoms of Parkinson’s Disease. By directly affecting mitochondrial respiration and assisting dopamine receptors and the use of dopamine in the brain.

ALCAR helps with Mild Cognitive Impairment (MCI)

A gold-standard double-blind, randomized controlled trial on 1,204 people showed significant effect on attention, mental performance, memory and higher mental functions.[xii]

In this study ALCAR seemed to ward off further brain deterioration. And could be considered as therapy for brain degeneration.

Acetyl-L-Carnitine slows rate of cognitive decline

130 Alzheimer’s patients were given ALCAR or a placebo daily for a year. They were tested across 14 points of cognitive performance.

This research showed a slower decline in cognitive performance with the ALCAR group compared to the placebo group.[xiii]

ALCAR effective for Chronic Fatigue Syndrome

acetyl-l-carnitine helps reduce chronic fatigueAcetyl-L-Carnitine has been shown to improve fatigue in patients with chronic fatigue syndrome.

In a randomized, double-blind, crossover study; 36 people were treated for 3 months with either amantadine (used to treat Chronic Fatigue), or 1 gram of ALCAR twice daily.

The results of the study showed that ALCAR was better tolerated and more effective for brain function than the pharmaceutical for fatigue.[xiv]

Acetyl-L-Carnitine protects from oxidative damage of Ecstasy (MDMA)

Research has shown ALCAR to be effective in protecting your mitochondria from oxidative stress. But these guys took it a step further.

Male rats were given Acetyl-L-Carnitine before a dose of Ecstasy (MDMA). ALCAR pretreatment “exerts effective neuroprotection against MDMA-induced neurotoxicity at the mitochondrial level”, said the researchers.[xv]

Keep that in mind before your next party.

ALCAR for Erectile Dysfunction?

Carnitine versus androgen administration. In this study, 120 patients were split into 3 groups. Group 1 was given 160 mg of testosterone per day. The 2nd group was given 2 grams of Propionyl-L-Carnitine plus 2 grams of Acetyl L Carnitine hcl per day. And the 3rd group a placebo.

Did you know that there’s an International Index of Erectile Function?

Turns out the Propionyl-L-Carnitine/Acetyl-L-Carnitine stack was better than testosterone for sexual dysfunction. Without the side effects of an enlarged prostate, better orgasms, more sexual desire and improved mood.[xvi]

Propionyl-L-Carnitine chemical structure


ALCAR Recommended Dosage

  • Acetyl-L-Carnitine suggested dosage for cognitive benefits is 1 – 4 grams per day.
  • For improved mood and elimination of chronic fatigue, 1 – 3 grams of ALCAR per day.
  • For age-related memory concerns, 1 – 2 grams of ALCAR per day.

ALCAR is water-soluble and can be taken on an empty stomach with water. A few supplement manufacturers recommend taking their Acetyl-L-Carnitine with a meal. Which may imply that it’s fat-soluble although I’ve found no evidence in the scientific literature.

ALCAR Side Effects

Acetyl-L-Carnitine is produced naturally in your body. So is considered well-tolerated and safe.

Side effects are rare but can include nausea, vomiting, increased agitation, weight loss, and restlessness.

You can also see an increase in seizure frequency if you have any kind of seizure disorder.

ALCAR and thyroid hormones. L-carnitine inhibits both triiodothyronine (T3) and thyroxine (T4) entry into the cell. Which means ALCAR supplementation may make thyroid hormone replacement therapy less effective. But could also help someone suffering from hyperthyroidism.

Types of ALCAR to buy

  • Acetyl-L-Carnitine: L-Carnitine with an extra acetyl group. This version of l carnitine is more bioavailable and easily crosses the blood-brain barrier.
  • L-Carnitine: This is the standard form of l carnitine found in food.
  • Lipo-Carn®: A proprietary blend of Alpha-Lipoic Acid and Acetyl-L-Carnitine. Studies show this combination is a powerful anti-aging duo.
    Performance Lab Energy contains an effective dose of ALCAR
    Performance Lab Energy contains an effective dose of ALCAR

    Together, these two help combat diabetes, glucose metabolism, boost energy production, lower high blood pressure, fat metabolism, maintain proper cognitive function, protects the body from radiation and chemical toxins and helps immunity.[xvii]

  • Propionyl-L-Carnitine: L-Carnitine combined with propionic acid. This form is noted for its antioxidant activity, reducing oxidative stress biomarkers, and is used for heart health applications. Also useful for erectile dysfunction.
  • Biosint™ is pharmaceutical grade Acetyl-L-Carnitine that is manufactured in Italy by Sigma Tau HealthSciences

You can also get 500 mg Acetyl L-Carnitine, 100 mg BioEnhanced R-Lipoic Acid, 100 mg CoQ10, 10 mg BioPQQ®, and 2.5 mg BioPerine® in one dose of my favorite energy supplement Performance Lab® Energy.

Nootropics Expert Recommendation

Acetyl-L-Carnitine 500 – 1,500 mg per day

Nootropics Expert Tested and Approved I recommend using Acetyl-L-Carnitine as a nootropic supplement.

Your body does synthesize some ALCAR on its own. And from the food you eat. But most L-Carnitine comes from red meat. And unless you eat a lot of great quality grass-fed beef or mutton you can not produce sufficient amounts, and likely have an Acetyl-L-Carnitine deficiency.

ALCAR is especially helpful for those suffering from age-related cognitive decline. Studies show it helps stop or reverse brain degeneration with Alzheimer’s Disease, and geriatric depression. Particularly in the early stages of the disease.

I suggest starting with a dose of 500 mg ALCAR daily. ALCAR is a great compliment to a stack including any of the racetams. Take enough Alpha GPC or CDP-Choline to eliminate a racetam-induced headache. Then add 500 mg of ALCAR.

Some have found ALCAR stacked with Coenzyme Q-10 has a profound effect on everything from mood to bipolar disorder. Especially combined with Alpha-Lipoic Acid.|

You can also get 500 mg Acetyl L-Carnitine, 100 mg BioEnhanced R-Lipoic Acid, 100 mg CoQ10, 10 mg BioPQQ®, and 2.5 mg BioPerine® in one dose of my favorite energy supplement Performance Lab® Energy.

Age-related cognitive disorders like Alzheimer’s may want to up the dose to 1,500 mg per day.

As an Amazon Associate I earn from qualifying purchases. This post may also contain other affiliate links and I will be compensated if you make a purchase after clicking on my links.

[i] Rebouche C.J. “Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism.” Annals of the New York Academy of Sciences 2004 Nov;1033:30-41. (source)

[ii] Liu J., Head E., Kuratsune H., Cotman C.W., Ames B.N. “Comparison of the effects of L-carnitine and acetyl-L-carnitine on carnitine levels, ambulatory activity, and oxidative stress biomarkers in the brain of old rats.” Annals of the New York Academy of Sciences2004 Nov;1033:117-31. (source)

[iii] White H.L., Scates P.W. “Acetyl-L-carnitine as a precursor of acetylcholine.” Neurochemical Research 1990 Jun;15(6):597-601. (source)

[iv] Kalaria R.N., Harik S.I. “Carnitine acetyltransferase activity in the human brain and its microvessels is decreased in Alzheimer’s disease.”Annals of Neurology 1992 Oct;32(4):583-6. (source)

[v] Berg J.M., Tymoczko J.L., Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002. (source)

[vi] Berg J.M., Tymoczko J.L., Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002. (source)

[vii] Costell M., O’Connor J.E., Grisolía S. “Age-dependent decrease of carnitine content in muscle of mice and humans.” Biochemical and Biophysical Research Communications 1989 Jun 30;161(3):1135-43. (source)

[viii] Gomez L.A., Heath S.D., Hagen T.M. “Acetyl-L-carnitine supplementation reverses the age-related decline in carnitine palmitoyltransferase 1 (CPT1) activity in interfibrillar mitochondria without changing the L-carnitine content in the rat heart” Mechanics of Aging Development 2012 Feb-Mar; 133(0): 99–106. (source)

[ix] Pettegrew J.W., Levine J., McClure R.J. “Acetyl-L-carnitine physical-chemical, metabolic, and therapeutic properties: relevance for its mode of action in Alzheimer’s disease and geriatric depression.” Molecular Psychiatry 2000 Nov;5(6):616-32. (source)

[x] Ferrari F., Gorini A., Villa R.F. “Functional proteomics of synaptic plasma membrane ATP-ases of rat hippocampus: effect of l-acetylcarnitine and relationships with Dementia and Depression pathophysiology.” European Journal of Pharmacology 2015 Jun 5;756:67-74. (source)

[xi] Taglialatela G., Navarra D., Olivi A., Ramacci M.T., Werrbach-Perez K., Perez-Polo J.R., Angelucci L. “Neurite outgrowth in PC12 cells stimulated by acetyl-L-carnitine arginine amide.” Neurochemical Research 1995 Jan;20(1):1-9. (source)

[xii] Montgomery S.A., Thal L.J., Amrein R. “Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer’s disease” International Clinical Psychopharmacology 2003 Mar;18(2):61-71. (source)

[xiii] Spagnoli A. et. Al. “Long-term acetyl-L-carnitine treatment in Alzheimer’s disease.” Neurology. 1991 Nov;41(11):1726-32. (source)

[xiv] Tomassini V., Pozzilli C., Onesti E., Pasqualetti P., Marinelli F., Pisani A., Fieschi C. “Comparison of the effects of acetyl L-carnitine and amantadine for the treatment of fatigue in multiple sclerosis: results of a pilot, randomized, double-blind, crossover trial.” Journal of Neurological Science 2004 Mar 15;218(1-2):103-8. (source)

[xv] Alves E. et. Al “Acetyl-l-carnitine provides effective in vivo neuroprotection over 3,4-methylenedioximethamphetamine-induced mitochondrial neurotoxicity in the adolescent rat brain” Cellular Neuroscience Volume 158, Issue 2, 23 January 2009, Pages 514–523 (source)

[xvi] Cavallini G., Caracciolo S., Vitali G., Modenini F., Biagiotti G. “Carnitine versus androgen administration in the treatment of sexual dysfunction, depressed mood, and fatigue associated with male aging.”Urology 2004 Apr;63(4):641-6. (source)

[xvii] Liu J., Head E., Gharib A.M., Yuan W., Ingersoll R.T., Hagen T.M., Cotman C.W., Ames B.N. “Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: partial reversal by feeding acetyl-L-carnitine and/or R-alpha -lipoic acid.” Proceeding of the National Academy of Sciences of the United States of America 2002 Feb 19;99(4):2356-61. (source)

Subscribe to the Nootropics Expert newsletter

Keep up to date with the latest developments in the nootropics space.

Head First 2nd Editon

The Award Winning Guide to Healing & Optimizing Your Brain with Nootropic Supplements.

Head First 2nd Edition

NEW! Eliminate Brain Fog, Low Energy, Moodiness, Difficulty Sleeping, Memory Loss or Anxiety. Available on Amazon, Barnes & Noble, Apple Books, Walmart and more...

Where to Buy Nootropics

Wondering where to buy nootropics? Well, you’re in the right place. Because here you will find the nootropic supplements that I personally use and recommend. Each supplement has a link to the company store and product that I use. I also include a link to my full review for each supplement here on Nootropics Expert® […]

The Definitive Guide to Nootropics

Nootropics can help increase your memory, boost learning ability, improve your mood and assist overall brain function. If you’re new to nootropics, or wonder about the difference between a nootropic and a smart drug, then this page is for you. Here you’ll find the definition of a nootropic, how to pronounce the word “nootropic”, the […]

The Most Comprehensive Nootropics List

This is our big list of the most popular Nootropics in use today. Here you’ll learn what each nootropic is, what it does and suggested dosages. What is this List of Nootropics About? Nootropic supplements are cognitive enhancers aiming to improve brain function. Whether you are looking to treat mild cognitive impairment, improve mental focus, or biohack […]

Free Secrets of the Brain 3rd Edition

Get “Secrets of the Optimized Brain,” 92 nootropics to help you plan your Nootropic Stack when you sign up for my newsletter:

Join The Discussion - 352 comments

Nick Naguib
May 22, 2024

Have been taking acetyl l-carnitine 1500mg/day, for the last 2 months/
On my test results last week found my potassium 5.4 , norman5.1
Also my Folic Acid 36.8 , Norman 34.8
Is any effect by keep taking l-carnitine on potassium &Folic acid levels.?

    David Tomen
    May 23, 2024

    Nick, ALCAR should not effect potassium or folate levels. But use ALCAR because L-Carnitine alone cannot cross the blood-brain barrier.

April 19, 2024

Hi David,

i have the side effect that I get quickly angry after taking ALCAR do you have any idea why? and do you have any alternatives to produce Acetylcholine with CDP choline? Thank you

March 1, 2024

Hi David!

I’m sorry if you’ve already answered this question but I tried looking through previous comments and didn’t find what I was looking for.

You wrote on another article “L-Tyrosine stimulates the production of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine)” and here I read L carnitine inhibits T3 and T4 hormones.

I’m curious to know your thoughts on taking ALCAR with L tyrosine. Is the inhibitory effect of L carnitine stronger than the excitatory effect of L tyrosine? Would ALCAR block some of the benefits to physical exertion that L tyrosine offers? And if that’s the case should I take ALCAR in the evening and L tyrosine in the morning to avoid interaction or take the two on differing days?

    David Tomen
    March 1, 2024

    Stu, that was my concern as well but found in the studies that it a was a lot higher dose of ALCAR that messed with thyroid hormones. I am severely hypothyroid and use 500 mg ALCAR twice per day with no problem.

December 27, 2023

hi …what dosage of alcar can improve d1 dopamine receptor?

    David Tomen
    December 28, 2023

    500 mg ALCAR twice per day.

Christian D.
November 6, 2023

Hello David,

I just found this about ALCAR:
“Serotonergic drugs interacts with ACETYL-L-CARNITINE”

Maybe this is of interest for you.

Thank you for your work, it has helped me a lot to understand.

BTW: I purchased your e-book “Head First” a while ago, but its information is on many places older than that on your website. It is dated on 2017. Please update it as much valuable information is only on your webpages. Thanks!

Many greetings

    David Tomen
    November 8, 2023

    Christian, I do not consider WebMD as a “trusted source” for anything. I have seen zero proof that ALCAR is contraindicated with drugs that affect serotonin.

    And you area correct that since the 1st Edition of Head First was published in 2017 a LOT of new neuroscience re. nootropics has surfaced. And that is reflected not only on this website but also in Head First 2nd Edition which you can get at any major bookseller. Here’s the link: BTW, Head First 2nd Edition has just won an award as well. So, well worth getting in my humble opinion. 🙂

October 25, 2023

Hi there!
My thyroid levels are heathy. Would you suggest using Acetyl-L-Carnitine, or would that affect them using the supplement long term?

    David Tomen
    October 26, 2023

    Should not be a problem.

October 20, 2023

could you add Intel on carnitine tartrate in “types of ALCAR to buy”

I stack carnitine with my morning coffee and taurine + lecithin with my afternoon coffee

    David Tomen
    October 25, 2023

    Mike carnitine tartrate and Acetyl L-Carnitine are two very different compounds. And it is only ALCAR that easily crosses the blood-brain barrier.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.