Saffron vs Glycine
for sleep
Stronger evidence: tie
Stronger effect: tie
Safety: No notable interactions recorded for either.
For sleep, the two are evidence-matched; the difference is in effect and safety.
Glycine
grade C low certainty
small trials suggest improved subjective sleep quality and reduced next-day fatigue
3 g before bed, adults
sources: PMID:41901246 · PMID:10000002