Acetyl L-Carnitine and L-carnitine are supplements that I’m being asked about more frequently these days by clients, so I thought a post was in order. Its only been about… forever since I wrote a post, so here it goes!
A little bit about the biology of L-carnitine to get started
L-Carnitine is a dipeptide made from the essential amino acids lysine and methionine, and as a result it is often classified as an “essential amino acid” itself. L-Carnitine has been shown to play an important role in cellular energy exchange. Specifically, L-carnitine is involved in transforming fats into energy in the mitochondria (which are basically little cellular power factories). There is also evidence that L-Carnitine can facilitate the metabolism of carbs by improving ATP production. As ATP is a critical molecule in making us LIVE, this is probably an important thing to support. With this in mind, its perhaps not surprising that L-Carnitine is found in highest concentrations in the heart and liver tissues. Importantly, there is some good evidence to suggest that L-Carnitine works synergistically with Co-Q10, an antioxidant and energy production cofactor that is found in the inner membrane of the mitochondria.
With this association between L-Carnitine and fat metabolism, some people refer to the supplement as a “fat burner.” As long branched chain fatty acids can only pass through the mitochondrial membrane as a result of esterification by Carnitine, there is some element of truth to the statement!
Enough biochemistry talk… lets get to the good stuff.
So there are some fairly decent studies showing that there are beneficial effects of L-carnitine supplementation for a variety of biological processes involving fat-loss, mortality and morbidiy and brain function that I’ll highlight below! Looks like a pretty good supplement overall, right?
I could keep going on this but instead I’ll just leave some links at the bottom of the page which illustrate the rather broad amount of research that has been done on L-carnitine. The list is not all inclusive…
So, what kind of supplement should I take???
So there are two kinds of Carnitine supplements that you are likely to run into, L-Carnitine and Acetyl-L Carnitine. They are based off of the same structure, but work slightly differently, notably the Acetyl form can pass through the blood brain barrier and therefore has more of a neurological effect. Another aspect is that Acetyl-L Carnitine may also provide substrate (acetyl groups) for synthesis of acetylcholine—a primary neurotransmitter in the brain. There is still some support for the idea that the Acetyl L-Carnitine can still help for converting fat into energy, but perhaps less as a primary benefit than the regular L-Carnitine claims.
I’ve read some claims that ALL the various forms of Carnitine will provide support for nervous system, cardiovascular system and muscles, but a specific form is probably preferred for a specific function. As I’m most comfortable with the research supporting the neurological benefits, I personally take the Acetyl-L Carnitine form, but to each their own!
SPECIFICALLY, I take 1000 mg of ALC with 200 mg of ubiquinol in the morning (around 10 am) to help get my brain rolling. Overall, I feel as though I see a benefit in my day to day functioning.
As usual, email with any questions!
Prada, P.O., Hirabara, S.M., de Souza, C.T., Schenka, A.A., Zecchin,H.G., Vassallo, J., Velloso, L.A., Carneiro, E., Carvalheira, J.B., Curi, R. & Saad, M.J. (2007) L-glutamine supplementation induces insulin resistance in adipose tissue and improves insulin signalling in liver and muscle with diet-induced obesity,Diabetologia, Volume 50, issue 9, (pp. 149-15
Wutzke, K.D. & Lorenz, H. (2004) The Effect of l-Carnitine on Fat Oxidation, Protein Turnover, and Body Composition in Slightly Overweight Subjects, Metabolism, Vol. 53, issue 8, (pp. 1002-1006)
Reda, E., D’Iddio, S., Nicolai, R., Benatti, P. & Calvani, M. (2003) The Carnitine System and Body Composition, Acta Diabetol, issue 40, (pp. 106-113)
Evangeliou, A. & Vlassopoulos, D. (2003) Carnitine Metabolism and Deficit – When Supplementation is Necessary? Current Pharmaceutical Biotechnology (pp. 211-219)
Müller, D.M., Seim, H., Kiess, W., Löster, H. & Richter, T. (2002) Effects of Oral l-Carnitine Supplementation on In Vivo Long-Chain Fatty Acid Oxidation in Healthy Adults, Metabolism, Vol. 51, issue 11, (pp. 1389-1391)