Caffeine Improves Attention & Focus: Meta-Analysis Evidence

Dr. Kumar’s Take

Caffeine doesn’t make you smarter — it makes you more awake, alert, and task-persistent. This meta-analysis quantifies that effect: measurable improvements in reaction time and sustained attention across task types, doses, and populations.

Key Takeaways

• Acute caffeine produces small-to-moderate gains in attention and reaction time.
• Benefits appear in both habitual and non-habitual users.
• Higher doses don’t always mean stronger effects; overstimulation can impair precision.

Actionable Tip

For mentally demanding tasks, 100–200 mg of caffeine (about one large cup of coffee) can sharpen attention for several hours.

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Nicotine and Cognitive Performance: What a Major Meta-Analysis Really Found

Dr. Kumar’s Take on Nicotine and Cognition

This meta-analysis pulled together 41 double-blind, placebo-controlled studies in healthy adults. It found that a single dose of nicotine can give small to moderate, short-term boosts in attention, reaction time, and some memory tasks. The effects were not due to withdrawal relief. These are lab gains, not a pass for daily use. Nicotine is addictive, raises heart rate and blood pressure, and can lead to dependence. If you use nicotine now, the safest path is planning to quit with evidence-based tools. If you do not use nicotine, the take-home is simple: do not start for “focus.”

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