N-acetyl-L-tyrosine

N-acetyl-L-tyrosine (NALT) is marketed as a nootropic for memory, concentration and cognitive endurance. In 2011 EFSA did not confirm the cognitive health claim (increased attention) for L-tyrosine; it did accept a role in normal catecholamine synthesis, but that is physiology rather than a memory benefit, and the label claim remains unauthorised. The N-acetyl derivative has no separate assessment. There are no RCTs comparing NALT with placebo or with L-tyrosine on cognitive outcomes in humans. Modest RCTs of free L-tyrosine suggest short-term support for concentration under an acute stressor (sleep loss, cold, multitasking) at roughly 100–150 mg/kg, but those data concern the free amino acid rather than NALT and address acute performance, not memory improvement in the general population. Biologically NALT must be deacetylated to tyrosine before entering the brain. In comparative animal pharmacology NALT was the least effective tyrosine prodrug, and there are no direct human data on how completely this conversion occurs, so the marketing claim of better bioavailability is not supported. If memory bothers the patient, start with sleep hygiene, ferritin, B12 and thyroid checks and discuss the request with a doctor before spending money on NALT.