Sleep supplements are a crowded, over-promised aisle. The honest version: a handful of nutrients have reasonable evidence, food sources come first, and none of them out-run caffeine at 4pm or a phone in bed.
The five worth knowing
Magnesium — the best-supported of the group, especially if your intake is low. Food first: pumpkin seeds, almonds, dark leafy greens, beans, wholegrains.
Glycine — an amino acid with small trials showing better subjective sleep quality; found in slow-cooked meats, bone broth and gelatine.
Tryptophan — the raw material for melatonin. Turkey, eggs, oats and dairy supply it; pairing with some carbohydrate helps it reach the brain.
Vitamin D — chronically low levels are linked with worse sleep; in the UK a winter supplement is standard advice anyway.
Omega-3s — emerging evidence connects oily fish intake to better sleep patterns. Two portions of fish a week, one oily, remains the anchor.
Before you buy anything
Fix the free levers first: consistent wake time, caffeine before noon, a dark cool room, and an honest look at alcohol — the most underrated sleep-wrecker in my clinic. If you're still stuck after that, bloodwork before supplements: low iron and thyroid issues both masquerade as 'bad sleep'.
