Acetyl L-Carnitine (ALCAR) is an acetylated form of L-Carnitine which is similar to typical L-Carnitine but is able to cross the blood-brain barrier. L-Carnitine is a compound naturally produced by the body which plays a key role in the mitochondrial oxidation of long-chain fatty acids.
When taken as a supplement, ALCAR supports exercise endurance and stamina, particularly for resistance training. Since ALCAR can cross the blood brain barrier, unlike the non-acetylated L-Carnitine it supports cognitive function and attention.
There is some evidence that ALCAR may worsen symptoms in people suffering from bipolar disorder so people with this condition should avoid ALCAR. There has also been some concern that ALCAR may interfere with the thyroid hormone at high doses so people with under-active thyroids may want to avoid ALCAR.