Here's a little info ive found on both of them. I would personally say get acetyl l-cartnitine because it seems to be a superior version of l-carnitine.
acetyl L-Carnitine (ALC) is the acetyl ester of carnitine, which transports fats into the mitochondria. In the mitochondria these fats are converted to an energy source. ALC is found in the brain but its levels are dramatically reduced as we age. Recent research has vaulted ALC as one of the premiere anti-aging compounds, especially in relation to brain and nervous system deterioration. ALC not only increases the release and synthesis of acetylcholine it now appears that it has neuroprotective and neuroenhancing properties as well. ALC can prevent dopaminergic neuron death by the neurotoxin MPTP which causes symptoms similar to Parkinson's disease. It has also been established that the density of NMDA receptors declines with age along with a decreased amount of NGF (Nerve Growth Factor). Treatment with ALC
restores the NMDA receptor numbers and enhances the effects of NGF.
L-Carnitine and ATP.
The amino acid l-carnitine is well known for its key role in the burning of fats. Specifically, l-carnitine transports fatty acids to the innermost section of the mitochondria (the cellular powerplants for energy) where they are used to create adenosine triphosphate (ATP), the energy currency of the body. Studies have shown that carnitine deficiency lowers ATP levels in various tissues. Carnitine deficiency also increases the susceptibility to fatigue from, and decreased the rate of recovery following, strenuous physical activity
Acetyl L-Carnitine (ACL).
Is the acetyl ester of the amino acid l-carnitine, which transports fats into the mitochondria. In the mitochondria these fats are converted to an energy source. It is a nutrient and naturally occurring metabolite that is involved in lipid, carbohydrate and protein, metabolism. ALC is naturally present in the human and animal body. The heart, brain, the muscles, and the testicles contain considerable concentrations of ALC but its levels are dramatically reduced as we age.
The esterified form is particularly well absorbed. As a matter of fact, when radioactively labeled ALC is administered, it is readily taken up in the cells. The distribution inside the cells was found to be 60% free l-carnitine, which was to be expected, and 40% ALC, which underscores the importance of this unique
substance in the body.
