See the DrugPatentWatch profile for advil

Based on the information available, Ibuprofen, the active ingredient in Advil, is typically quickly absorbed in the body and can start relieving pain within 30 minutes after ingestion [1]. However, the time it takes for a headache to be alleviated can vary from person to person, depending on factors such as the severity of the headache, the dosage taken, and individual body chemistry.

It is important to follow the recommended dosage and usage instructions provided by the manufacturer or a healthcare professional to ensure the safe and effective use of Advil. If a headache persists for an extended period of time or is accompanied by other symptoms, it is recommended to seek medical attention.

Sources:
[1] <https://www.drugpatentwatch.com/ibuprofen>