Instant coffee. Two jars of instant coffee, regular (right) and decaffeinated (left). Caffeine is a central nervous system stimulant, used to increase

---

Instant coffee. Two jars of instant coffee, regular (right) and decaffeinated (left). Caffeine is a central nervous system stimulant, used to increase alertness and reduce physical fatigue. High use can result in physical dependence and subsequent withdrawal, as well as anxiety disorder and insomnia.

---

Size: 4217px × 4217px
Photo credit: © Science Photo Library / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: alert, alertness, background, beverage, boost, caffeinated, caffeine, coffee, compared, comparison, cut, cutout, decaf, decaff, decaffeinated, dependence, diet, drink, drug, fatigue, fluid, food, glass, insomnia, instant, jar, liquid, natural, night, pair, prevention, product, psychoactive, sleeplessness, stimulant, treatment, white, withdrawal