Alan raises his self-confidence by spraying a 'hair-like substance' on his head. He takes pills as well. Charlie doesn't think it's a realible product, because there's a monkey on the label (it's actually the inventor). The song Alan sings while spraying hair on his head, is called 'Blame It on the Bossa Nova', by Eydie Gormé. Season 7, episode 9 (Captain Terry's Spray-On Hair). I do not own the rights of the content in this video.