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)

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Join The Discussion - 358 comments

October 1, 2023

Hi David,

Continuing my research for a low-energy booster stack. ALCAR is a good contender. I tried some at 500mg by itself and experienced a low-grade headache (very minor maybe 3/10). Added B12, B6, and B5. They helped take it down to 2/10. Then I tried it at 250mg 1/10.

In all scenarios, the headache starts 30-45 min from digestion and clears up at the 1:30h mark. It goes in small waves, peaks, and then subsides. I noticed good focus/mission drive on it the entire time.

[edited for length]

Best regards,


    David Tomen
    October 1, 2023

    Julian, try to summarize your question into 1 or 2 sentences please. I do not do nootropic stack reviews either in this comments thread. For that you’ll need to schedule a consultation with me.

    This is one of several articles I written on energy which may offer some ideas for you to try:

      October 1, 2023


      My bad. In a sentence, what would cause a very minor headache with ALCAR? Not enough vitamins?

      Could the brand of ALCAR be at fault?

        David Tomen
        October 2, 2023

        Julian, one of the things ALCAR does is boost Acetyl-CoA which is needed for acetylcholine synthesis. But that cycle also needs a choline molecule. So, most pair ALCAR with either CDP-Choline or Alpha GPC. That combo “may” get rid of your headacje.

        October 2, 2023

        David, I tried with and without choline. About the same result. Today I tried it again at 500mg with another ratio of Bs and choline. Didn’t seem to have a headache.

        So perhaps the other times were all flukes. Maybe I was low on water or something. Anyway, I’ll continue experimenting.

September 2, 2023

Hi David,
I can see that ALCAR might affect Thyoid hormones, which I’m not really fond of. Does it do it at a significant level?

Also, is AlpaGPC, or Choline ,enough for acetylcholine? If not, are there other alternatives that you suggest?

Thank you

    David Tomen
    September 4, 2023

    Andrei, I have the same issue because I need to increase acetylcholine but am severely hypothyroid and use thyroid meds. So I limit myself to one 500 mg ALCAR capsule per day and that seems to be enough. That does not seem to mess with my thyroid levels in a noticeable way.

    You use ALCAR with Alpha GPC or CDP-Choline because ALCAR helps produce Acetyl Co-A which is part of the synthesis cycle to make acetylcholine.

August 16, 2023

Hello David,

do i have to take ALCAR with Alpha GPC or CDP Choline to increase acetylcholine, or is it enough to take ALCAR alone to boost acetylcholine?

thanks a lot

    David Tomen
    August 21, 2023

    ALCAR only increases Acetyl-CoA which is used in the synthesis of acetylcholine. You still need a choline supplement to complete that cycle.

Mark Painter
May 3, 2023

David, I experience headaches pretty quickly after ALCAR 500mg that last for a few hours. Do you think this could be a result of low acetylcholine levels? Wondering if I need to focus on supplements like Alpha GPC for a while. Thanks

    David Tomen
    May 5, 2023

    Mark ALCAR is sometimes used to treat migraines ( The theory is a deficiency in carnitine could cause the headaches and ALCAR helps restore that carnitine in mitochondria. This is pure speculation on my part but maybe you already have plenty of carnitine in your system. So, supplementing with ALCAR pushes you over the edge to excess carnitine.

April 24, 2023


Can I take DLPA/L-tyrosine with L-tryptophan and Acetyl-L-carnitine? Any interactions?

    David Tomen
    April 26, 2023

    Jman, you certainly can but you’ll likely want to use L-Tryptophan before bed because it is a precursor to serotonin which goes on to produce melatonin.

Ryan Smith
March 27, 2023

Thank you for the article. I have been taking ACLAR and ALA together

Best Naturals – Acetyl-L-Carnitine-Alpha Lipoic Acid

Mostly I take 1 pill in the morning. Sometimes a second mid day

I have always had issues sleeping (I’m going to try your recommendation on a sleep stack), but more recently it seem like my sleep has been much worse.

Do you think the increased sleep issues could be from this product?

    David Tomen
    March 31, 2023

    Ryan, that supplement is likely causing insomnia because that combo is usually used as energy booster. Those two supplements are including in Performance Lab Energy for example along with CoQ10 and PQQ. So, either use it in the morning, or cut the dose in half, or stop using it if the problem persists.

March 14, 2023

Hi David,

I have read that ALCAR should be taken with carbs, which releases insulin, and subsequently increases the uptake of ALCAR into your muscle cells. But I am trying to understand if this increase only benefits muscles and exercise performance, or would it additionally improve its cognitive efficacy.


    David Tomen
    March 20, 2023

    Ryan, it very well could improve cognition although I don’t have any research to back that up.

March 4, 2023


I have a question on this exerpt in your expert recommendation section:

‘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.’

Does this mean ALCAR stacked with CoQ10 and Alpha-Lipoc Acid is favorable (e.g., especially when also combined with…)?
Or were you specifically talking about ALCAR + Alpha-Lipoic Acid only in the last statement?


    David Tomen
    March 6, 2023

    Chris, the combination of Alpha Lipoic Acid, ALCAR and CoQ10 works very well. It works so well that Performance Lab stacks those 3 with PQQ in their Energy supplement.

      March 12, 2023

      Great, thanks for the reply

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