Research

Mixed

Single doses of caffeine (600 mg), dextroamphetamine (20 mg), and modafinil (400 mg) are equally effective at restoring psychomotor vigilance speed and objective alertness for approximately 2–4 hours during 85 hours of total sleep deprivation.

If you are severely sleep-deprived, a single high dose of caffeine (600mg) works just as well as prescription stimulants like modafinil or amphetamines for restoring basic reaction times and alertness for about 2-4 hours. However, these drugs do not restore complex executive functions (like planning or decision-making) equally, and prescription stimulants may actually impair some executive tasks. The benefits are short-lived, so these are temporary countermeasures, not cures for sleep loss.

GoodSupportsHIGH confidence
At the doses tested, caffeine, dextroamphetamine, and modafinil are equally effective for approximately 2–4 h in restoring simple psychomotor performance and objective alertness.
Nancy J. Wesensten et al. · Journal of Sleep Research · 2005

Why this rating

Randomized, double-blind, placebo-controlled trial with a large sample size (n=48) and rigorous sleep deprivation protocol (85h).

Source

Performance and alertness effects of caffeine, dextroamphetamine, and modafinil during sleep deprivation

Nancy J. Wesensten et al. · Journal of Sleep Research · 2005

DOI 10.1111/j.1365-2869.2005.00468.x

rct · n=48Cited 305×
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DOI resolved against Crossref · corpus check 2026-06-10

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