L-Carnitine or Acetyl-L-Carntine… What’s the difference?

Given all the potential benefits of L-Carnitine, you may decide to supplement. Yet, when you go to the shelf you can be confronted with Acetyl-L- Carnitine, and wonder which is better? The answer is it depends on what you are using it for.

If you are looking for neurological/ brain benefits, or anti-aging effects I would say to try Acetyl-LCarnitine. On the other hand, if you are looking to burn more body fat, maintain muscle, or derive heart/cardiovascular benefits, I would recommend L-carnitine. (This is explained and referenced below.) Either way, the list of benefits is long indeed!


L-Carnitine... The basics

For those who have read my blogs over the years, you’ll know that I am a huge fan of anything that supports energy production by improving the function of our cellular furnaces called mitochondria. For this L-Carnitine is absolutely essential. Specifically it is essential to be able to burn fat! [1]

As I have explained many times, picture carbohydrates, protein and fats being transported on conveyor belts into your mitochondria to be burned for energy. Ensuring that you have ample L-Carnitine simply tips up the fat conveyor making it more likely that you will burn fat as fuel…and fat is a good source of energy, containing more than twice the calories of either protein or carbohydrate. Hence, you produce more energy with the added benefit of mobilizing triglycerides and free fatty acids from the blood and body, thereby also helping improve insulin sensitivity.[1] [2] [3] 



And though your body can produce L-carnitine, this happens at a major cost to your muscle mass. In fact, to synthesize 1 gram of L-carnitine, your body has to break down over 30g of muscle tissue. [4] Yet, for those looking to reduce body fat, they need that muscle to burn fat. Hence, a carnitine deficit starts a vicious cycle. Likewise, those looking to build muscle mass would be well advised to ensure their intake of L-Carnitine. [4]

Instead of using up their muscle tissue most would prefer to get L-Carnitine from their diet. Yet, since it is only available from animal protein, such as red meat (particularly beef), seafood, other meats, and dairy products, this means vegetarians, especially vegans who eat no animal protein, are at particularly high risk for a functional deficiency. Meaning that though they may not be clinically carnitine-deficient, they would reap many benefits if they had more…(the difference between thriving versus simply surviving.)

Further, because one of the enzymes required for synthesis does not develop until approximately the age of 15, vegetarian kids are at particular risk of functional deficiencies.[4] Given the number of functions it serves in the body, and the body’s preference for dietary L-carnitine, many consider it semi-essential. (For more information details and applications of L-carnitine you can view my prior article)

Read Part 1: L-Carnitine: Burn Fat, Increase Energy, Improve Your Health.



The addition of the acetyl group on carnitine allows Acetyl-L-Carnititne (ALCAR) to cross the blood-brain barrier and be absorbed into the brain. [5] It not only enhances energy production in the brain and central nervous system, it also supports memory and alertness by aiding in the production of neurotransmitters such as acetylcholine and dopamine. [6] [7] [8] [9] This makes it appropriate consideration for anyone looking to improve overall brain status and performance, or to reduce aging in general. [3]



In addition, Acetyl-L-Carnitine has been studied extensively for its application in several neurological conditions. Due, in part, to its ability to boost neurotransmitter production, several studies have noted significant positive results for the effects of ALCAR on depression. [10] Additionally, ALCAR can protect our brain from the damaging effects of toxins, including excess alcohol. [11] In another study, primates given a substance called MPTP, which normally damages brain cells and induces Parkinson’s disease, were completely spared these effects if they were treated with ALCAR first. [12] [13] ALCAR has been scrutinized for its application in Parkinson’s disease. [17] ALCAR has also been shown to slow progression of dementia and/or Alzheimer’s disease, and improve performance for these patients on test challenges, as well as being helpful for preventing and/or improving diabetic neuropathy. [14] [10] [15] Fibromyalgia is another condition that has been shown to respond positively to ALCAR. [16]

 In terms of how you feel, in my experience, people notice both forms of carnitine make them more energetic and optimistic. Yet this effect is more pronounced and common with Acetyl-L-Carnitine. So if it is mood, energy, or feeling of well-being your after, I would suggest trying the this form first.


Regarding dosage If you are looking for maintenance, then one or two 500mg capsules a day will suffice. If you are looking for a most pronounced effect, 2 capsules, twice a day is what I normally recommend. As either form will increase your energy and alertness, morning and afternoon are the preferable times for supplementing. Though you will still absorb some L-Carnitine if taken with food, either form will be more noticeable if taken on an empty stomach.

Lastly, I would say it takes about a month, (give or take), to notice results.

Hope you find this information useful.

Be well,



Sources and References:

  1. Carnitines, Acylcarnitines and Beta-Oxidation: The LipidWeb; lipidmaps.org. Nov/21.
  2. Review: Role of carnitine in disease; Nutrition and Metabolism, 2010; Authors: JL Flanagan et al. See: http://www.nutritionandmetabolism.com/content/7/1/30
  3. Carnitine: The Science behind a Conditionally Essential Nutrient; The Office of Dietary Supplements, National Institutes of Health; 2004 symposium proceedings. See:http://ods.od.nih.gov/News/Carnitine_Conference_Summary.aspx
  4. Nutritional Medicine Update: The Clinical Applications of L-Carnitine; Robert Crayhon interviews with Stefan Siebrecht, PHD, and Salvatore Benvenga M.D. see: http://www.letstalkrealhealth.com/dr-stefan-siebrecht-phd-dr-salvatore-benvenga-md-clinical-applications-of-l-carnitine/
  5. http://www.ncbi.nlm.nih.gov/pubmed/14595704 6.
  6. http://link.springer.com/article/10.1007%2FBF00973749?LI=true 
  7. http://www.nature.com/npp/journal/v27/n3/full/1395896a.html
  8. http://www.direct-ms.org/sites/default/files/Ames%20Delaying%20Aging%20with%20ALCAR.pdf 
  9. http://www.lef.org/magazine/mag2011/aug2011_Interview-with-Dr-Bruce-Ames_01.htm
  10. Acetyl-L-Carnitine Monograph - Alternative Medicine Review 
  11. http://www.wellnessresources.com/health/articles/acetyl-l-carnitine_protects_the_brain_from_alcohol-induced_damage/ 
  12. http://www.ncbi.nlm.nih.gov/pubmed/2064731 MPTP 
  13. http://www.ncbi.nlm.nih.gov/pubmed/15219812 MPTP
  14. http://www.ncbi.nlm.nih.gov/pubmed/1944900 
  15. http://www.theannals.com/content/42/11/1686.short 
  16. http://www.ncbi.nlm.nih.gov/pubmed/17543140 
  17. http://cdn.intechopen.com/pdfs/27860/InTech-Acetyl_l_carnitine_in_parkinson_s_disease.pdf

1 comment

Thank you for well versed explanation explanation especially supporting with references.

Mualla January 28, 2022

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