The Compendium of Caraka 8.9.100

8.9.100

dadyānnāsāpuṭe snehaṃ tarpaṇaṃ buddhimān bhiṣak/
anavākśiraso nasyaṃ na śiraḥ pratipadyate//

The intelligent physician should instill the nourishing unctuous substance into the nostrils. / Nasal medication given to one whose head is not lowered does not reach the head;