(Acetyl) L-carnitine  is..

(L-carnitine) is an amino acid derivative found in nearly all cells of the body. It is responsible for transporting fatty acids into the mitochondria – the internal combustion centers of the cell.. Fatty acids play a major role in the energy production of heart and muscle tissues.

L-carnitine appears to protect heart and muscle tissues against the damaging effects of low blood flows (ischemia). It also appears to lower the levels of damaging fats called triglycerides and to increase levels of the ‘good’ cholesterol (HDL cholesterol). Some preliminary evidence suggests L-carnitine may be beneficial in kidney disease and AIDS. There is little evidence that L-carnitine increases energy or boosts athletic performance or fights obesity.

L-carnitine May Work in Chronic Fatigue Syndrome (ME/CFS) Because…

it enhances mitochondrial production and protects against the negative effects of low blood flows both of which may be present in chronic fatigue syndrome (ME/CFS).

Chronic Fatigue Syndrome (ME/CFS) Studies

One chronic fatigue syndrome study found reduced acetyl-L-carnitine uptake in several parts of the brain involved in producing fatigue,. Another found normal plasma carnitine levels. Acetyl-L carnitine and propionyl carnitine improved mental fatigue and general fatigue respectively in another chronic fatigue syndrome study.

ME/CFS patients with low acetylcarnitine levels responded better to azithromycin in another study. Intriguingly, acetyl-L-carnitine was more effective that amantadine in treating fatigue in another severely fatiguing disease, multiple sclerosis. Acetylcarnitine therapy has not been studied in FM.

Side Effects

Generally well tolerated; gastrointestinal symptoms (cramping, diarrhea, nausea, vomiting) have been reported. A very low incidence of seizure has also been reported.


Typically 500 milligrams to 2 grams daily taken with or without food. At higher levels it is advisable to break up the doses. Can be found as either L-carnitine or acetyl-L-carnitine. Propionyl-carnitine is available in Europe. Avoid DL-carnitine.

(This and all sections of the Phoenix Rising website are compiled by a layman. They are not a substitute for a physician and are for informational uses only. Please discuss any treatments in these pages with your physician.)


Azithromycin in Chronic Fatigue Syndrome (CFS) an analysis of clinical data. Vermeulen, R.C., Scholte, HR. In J. Transl. Med. 2006, 4: 34.

Exploratory Open Label, Randomized Study of Acetyl and Propionlycarnitine in Chronic Fatigue Syndrome. Vermeulen, RC, Scholte, HR. In. Psychosom Med. 2004, 66:276-282.

Brain Regions Involved in Fatigue Sensation: reduced acetylcarntine uptake into the brain. Kuratsune, H., Yamaguti, K, Lindh, G, etc. N. Neurol Sci 2004 218: 103-18.

Acetyl -L-carnitine and Disease: L-carnitine deficiency can occur because of genetic defects or as a result of other conditions including adrenal insufficiency, low pituitary functioning, AIDS, cirrhosis and pregnancy.

PDR Health: L-carnitine


{ 3 comments… read them below or add one }

Lorelei March 13, 2013 at 8:51 pm

I have read that l-carnitine and acetyl-l-carnitine have different effects. I am not sure if I am recollecting correctly that l-carnitine acts more on the body while acetyl-l-carnitine can cross the blood-brain barrier. I think the recommended dosage of each one is different, as well. It’s probably best to look into them in detail before choosing to use one or the other, both, or neither.


Leopardtail March 25, 2014 at 6:54 am


they are all carnitine just different version’s of it. You are quite right the different versions have different effects.

As yet I have not been able to find research that thoroughly enough assesses how well different forms actually get into cells, but there are definitely differences in how much shows up the blood stream.

What is known is that Acetyl-L-Carnitine has an extra role: it can replace Acetyl-L-Choline a Neurotransmiter (= brain hormone) that plays keys roles in the para-sympathetic nervous system and in motor control.

So far as energy generation is concerned all forms of Carnitine get transformed into Acetyl-L-Carnitine within cells before being transported into Mitochondria (= the cell’s energy generator). To this other chemicals are ‘bonded’ to it hence one molecule of ALCAR will weigh more than one of a simpler Carnitine hence the probable need for higher doses. It does however tend to be much cheaper than other more ‘active’ forms.


Leopardtail March 25, 2014 at 7:07 am

The link from the image above is dead, and while I can’t see it properly, there appears to be a slight inaccuracy.

Bigger, more readable image here: https://en.wikipedia.org/wiki/File:Acyl-CoA_from_cytosol_to_the_mitochondrial_matrix.svg


Leave a Comment