<|im_start|>user
What is caffeine?<|im_end|>
<|im_start|>assistant
Caffeine is a stimulant that people ingest in order to get a boost of energy.  One of the most common forms of ingested caffeine is coffee.  Caffeine gives you energy for a short while but it is often followed up with a feeling of being tired, sleepy or lethargic.  People use caffeine as a performance enhancer, mood and brain booster and increased alertness.<|im_end|>
