The L-Carnitine Conundrum strikes back! Looks like inquiring minds want more on this enigmatic supplement.
What is Carnitine?
Carnitine is a amino acid derivative that transports long-chain fatty acids across the inner mitochondrial membranes to form adenosine triphosphate or ATP, the basis for virtually all cell energy. The bottom-line is you need this stuff to survive. Click Here for more.
What is with the "L" - why not just call it Carnitine?
Good question. Carnitine is a stereoisomer which means it exists as two atomically identical compounds that are mirror images. For example, look at your hands. They are identical in composition and structure yet are "arranged" differently (left-handed and right-handed). The "L" stands for "levo" and denotes that this particular form of the carnitine molecule "twists" to the left. There is also "D-Carnitine." The "D" stands for "dextro" and means this form twists to the right. Although they are atomically equivalent the twist makes them behave differently. Suffice to say that only L-Carnitine provides biochemically available carnitine to the body.
What is with all the different preparations?
Here is the quick list.
L-Carnitine: Sometimes (though incorrectly) called just Carnitine, this is what your body needs. Click Here for more.
Acetyl L-Carnitine (ALCAR): The action of ALCAR is similar to L-carnitine. There is speculation that it is better absorbed than L-carnitine, but this has not yet been definitively established. Click Here for more
Propionyl L-Carnitine (PLC): It seems some in the research community have a dubious preference for PLC because of a report that it has a higher affinity for the plasma membrane transport system, being more lipophilic (disolvable in fats) and penetrating better than L-carnitine (Lango, R., Smolenski, R. T., Narkiewicz, M., Suchorzewska, J., and Lysiak-Szydlowska, W. (2001) Cardiovasc. Res. 51, 21-29). I cannot find a study with enough power to statistically substantiate whether this is true or not.
Does it work?
Well, yes and no. If you are carnitine deficient, this supplement works wonders on numerous levels (see previous blog). Deficiency can occur if you are undergoing dialysis, on a strict diet that limits sources of natural L-Carnitine, or have some sort of genetic deficiency. There are several heart related conditions that, when severe, seem to benefit from L-Carnitine supplementation. A good example is Peripheral Artery Disease (PAD). Severe sufferers seems to benefit substantially but the effect tapers off as the severity of the disease tapers off. In one prominent study, athletes gained no advantage from L-Carnitine.
The bottom-line seems to be that L-Carnitine can be useful if you have a carnitine related problem but adds no additional beneficial effect if you are healthy. It also has few toxicity or adverse reaction problems so is not likely to be dangerous. However, note this supplement is banned in Canada and is available only by prescription as it is considered a drug there.
Could L-Carnitine help you? Maybe, I tried it (to no avail). Just be objective. Don't believe everything you read in health magazine supplement ads. Ask yourself, "Do I feel better. Did my lipids improve? Did my calcium score go down?" Remember, we are all different. What works for some will not work for others. Unfortunately, there isn't enough evidence to say, absent disease or deficiency, that it will PROBABLY help you.