correlational
Taking glycine before bed doesn't seem to change the overall structure of sleep stages, according to sleep monitoring equipment.
Scientific Claim
Glycine ingestion (3 g) before bedtime was associated with no changes in sleep architecture in individuals with chronic unsatisfactory sleep, as measured by polysomnography.
Original Statement
“Glycine improved subjective sleep quality and sleep efficacy (sleep time/in-bed time), and shortened PSG latency both to sleep onset and to slow wave sleep without changes in the sleep architecture.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study is an observational cohort with unclear randomization and control group status, so causal language ('without changes') is inappropriate. Only association can be claimed.
Evidence from Studies
No evidence studies found yet.