The Claim

A 100mg dose of caffeine administered at bedtime prolongs sleep latency and reduces sleep efficiency in healthy young adult males.

Source: Caffeine Reduces Low-Frequency Delta Activity in the Human Sleep EEG

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
41score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

Taking 100mg of caffeine at bedtime increases the time it takes to fall asleep and decreases the percentage of time spent asleep while in bed for healthy young adult males.

See the scientific wording

A 100mg dose of caffeine administered at bedtime prolongs sleep latency and reduces sleep efficiency in healthy young adult males, indicating a measurable disruption in the ability to initiate and maintain sleep.

Why this might work

Caffeine enters the brain and sticks to sleep-promoting receptors, preventing the natural buildup of a chemical that tells the brain it's time to sleep. This stops the brain from generating the slow, synchronized electrical activity needed to fall asleep and stay in deep sleep, making it harder to fall asleep and reducing total sleep time.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Caffeine Reduces Low-Frequency Delta Activity in the Human Sleep EEG

    Taking 100mg of caffeine before bed made it harder for young men to fall asleep and caused them to sleep less overall, according to this study. So yes, caffeine before bed messes with sleep.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.