Oddly, this suggests that, among those who did not regularly drink caffeinated drinks, caffeine improved their sensitivity to smell but reduced their ability to identify odors. The authors say that caffeine’s stimulant effects may have had a more pronounced impact on performance during the odor sensitivity test given that it was a longer, more tedious task than the identification test.

— Read more in Caffeine enhances odor sensitivity among people who don’t typically consume caffeine, but not among regular consumers at PsyPost.