Does caffeine still enhance memory when it doesn’t work on me?

Yes—caffeine may still help memory even if you don’t notice its usual stimulating effects, but individual responses vary. The discussion describes caffeine as increasing alertness and supporting memory, while noting that some people are unusually insensitive to its effects. 1

• After learning: Caffeine taken immediately after studying may support memory consolidation by increasing catecholamines such as dopamine, norepinephrine, and adrenaline, which help strengthen memories of information encountered just before the increase. 2
• Before learning: Caffeine may also help when taken before a memory task by increasing alertness and making learning-related circuits easier to access; the timing of caffeine’s effects matters, and taking it after learning may be more effective for retention. 3 4
• Expectations: In a study, students who received caffeine but thought they had taken Adderall reported stronger stimulant effects and performed better on a working-memory test—suggesting expectations can influence perceived effects and performance. 5