Intranasal essential oils in therapy: advances in clinical applications and delivery mechanisms.

This review comprehensively examines the therapeutic mechanisms, formulation advancements, and clinical applications of intranasal essential oil (EO) delivery, aiming to highlight its potential as a modern therapeutic approach. A systematic literature search was conducted in PubMed and Web of Science up to May 2024, focusing on preclinical and clinical studies. Data on target diseases, delivery mechanisms, formulation innovations, and therapeutic effects were extracted and analyzed. Intranasal EO delivery demonstrates significant therapeutic potential for neurological, respiratory, cardiovascular, and metabolic disorders. Advanced delivery systems, including nanoemulsions, liposomes, and nasal in situ gels, enhance EO stability, bioavailability, and targeted release. Mechanistically, EOs exert effects through neurotransmission modulation, anti-inflammatory pathways, and vascular regulation, primarily via the olfactory and trigeminal nerves. Clinical evidence supports the efficacy of intranasal EOs in conditions such as anxiety, depression, allergic rhinitis, and hypertension, although further optimization is needed to minimize irritation and improve patient adherence. Intranasal delivery of EOs offers a promising strategy for enhancing therapeutic administration and expanding clinical applications. Future research should focus on developing advanced in vivo pharmacokinetic evaluation tools, optimizing delivery systems, ensuring safety, and integrating EOs with conventional therapies to support their broader clinical translation.