Histidine-containing dipeptide supplementation improves delayed recall: a systematic review and meta-analysis.

This article systematically reviews and meta-analyzes randomized controlled trials (RCTs) assessing the effects of histidine-containing dipeptides (HCDs)—including carnosine, anserine, and beta-alanine—on cognitive performance in humans. The meta-analysis of 10 RCTs involving 730 participants found that HCD supplementation significantly improved delayed recall memory, as measured by the Wechsler Memory Scale-2 (WMS-2), particularly in older adults over 65 years and in individuals without mild cognitive impairment (MCI). No significant effects were observed on other cognitive tests such as the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), or digit span tests. The study highlights the need for larger, well-characterized clinical trials with standardized dosing and longer follow-up to clarify the cognitive benefits and mechanisms of HCD supplementation.