ALCAR

Acetyl-L-carnitine (ALCAR) is an acetylated form of the amino acid derivative L-carnitine. It occurs naturally in human tissues and is also available as a dietary supplement. Chemically, it is the acetyl ester of L-carnitine and is more lipophilic, which allows it to cross cell membranes and the blood-brain barrier more readily than L-carnitine.

In metabolism, carnitine normally facilitates the transport of long-chain fatty acids into mitochondria for beta-oxidation. The acetylated form, ALCAR, can also donate acetyl groups to acetyl-CoA pools and participate in protein acetylation, potentially supporting mitochondrial function and energy production. In the brain, ALCAR is thought to influence acetyl-CoA availability and neurotransmitter synthesis, and may positively affect neuronal energy metabolism and plasticity in some contexts.

Clinical evidence for ALCAR is mixed. It has been studied for aging-related cognitive decline, mild cognitive impairment, depression, and peripheral neuropathy. Some small trials report modest cognitive or mood benefits, particularly in older adults, but many studies show no significant effects. ALCAR is not approved as a prescription treatment for any condition, and claims about its benefits are not evaluated by regulatory agencies such as the FDA. The quality and consistency of evidence vary by condition.

Safety and regulation: ALCAR is generally well tolerated, with possible side effects including gastrointestinal upset, headache, restlessness, or insomnia. Serious adverse effects are uncommon. As with any supplement, individuals should consult healthcare providers before use, especially if pregnant, nursing, taking medications (including anticoagulants or thyroid drugs), or managing a medical condition.