One standing challenge for Alzheimer's disease (AD) research is early diagnosis, which provides a time window for early intervention. Sharmin et al recently reported a positive association between plasma ptau181 and plasma metabolites, medium- and long-chain acylcarnitines (ACs) in both cognitively normal (CN) Aβ- and CN Aβ+ older adults, suggesting a link between initial Aβ pathology and acylcarnitine-mediated energy metabolism pathways. Consistently, ACs could classify PET-Aβ status in elderly individuals. This study has provided further clues for early biomarker searching for AD, linking metabolic pathways with AD pathogenesis.