What it’s for
- Alertness and exercise performance
A stimulant in coffee, tea and other foods, drinks and supplements.
Purpose, evidence and practical considerations.
Caffeine can improve alertness and performance, but can also disrupt sleep. A 90–120-minute delay after waking is not an established requirement; total intake and timing relative to bedtime matter.
Confidence: strong
Caffeine can cause anxiety, tremor, palpitations, reflux and sleep disruption. Concentrated powders create overdose risk. Pregnancy, cardiovascular conditions and interacting medicines may require lower individualized limits.
Caffeine blocks adenosine receptors, reducing sleep pressure and increasing alertness. Effects vary with dose, habitual use, genetics and timing relative to sleep.
Regulatory status: common food constituent and dietary supplement ingredient; also used in some approved medicines
The evidence on this page does not automatically apply to:
How people use it, with their schedules, context and original sources.
delayed 90–120 min after waking
Amount and timing patterns reported in public protocols; these are observations, not instructions. Private and hidden usage is excluded.
These share a protocol with this intervention. This does not establish that they work together or are suitable alternatives.
He prefers steadier mood and avoiding dependence.
no coffee after 6 pm