GLOSSARY

Focus Supplement is a product intended to improve alertness or attention, whose stimulant content, actual effect and sleep consequences require review.

Caffeine antagonizes adenosine receptors and can improve selected endurance, alertness and high-intensity outcomes. Response varies with dose, task and individual sensitivity. More caffeine is not necessarily more effective, and side effects can outweigh a modest performance benefit. Count caffeine from coffee, gels, drinks, tablets and combinations together. Sleep disruption, anxiety, gastrointestinal symptoms and cardiovascular complaints deserve attention. Pure concentrated caffeine powders pose a particular dosing hazard; a product's stimulant effect is not proof of adequate or safe fueling.

Caffeine delivery and clearance vary with formulation, food, metabolism, medication and individual physiology. Chewing gum and swallowed products can have different absorption patterns, while the amount in coffee can vary. CYP1A2 contributes importantly to metabolism, producing metabolites including paraxanthine. Habitual intake and withdrawal can influence study interpretation, but complete abstinence is not a universal requirement for benefit. A single genotype does not reliably determine every performance response. Consider both the intended session and the possibility of residual effects on later sleep.

The dose refers to the amount of the relevant active ingredient, not necessarily the mass of powder or the number of scoops. A single dose, daily total and body-mass-relative dose describe different quantities. Larger amounts can increase adverse effects without improving performance. Loading, maintenance and acute timing are ingredient-specific strategies rather than universal rules. Check all products used together so that repeated ingredients do not create an unintended total intake.