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Sleep · lesson 8 of 11

Sleep supplements: what actually works

Melatonin, magnesium, glycine, theanine — signal vs. hype.

7 min read · reviewed October 2026

Fix behavior first, then consider these

Supplements are the last 10% — they can't out-muscle bright evening light, a late coffee, or a chaotic schedule. Fix those first. That said, a few have real support:

Melatonin: timing, not a sledgehammer

In plain terms

Melatonin is a timing signal, not a sedative. A small dose (0.5–1 mg) taken a few hours before bed can nudge your clock earlier; large doses don't work better and can leave you groggy.

How it works →

Melatonin's main evidence-based use is as a chronobiotic — shifting circadian phase (jet lag, delayed sleep phase) — taken in the early evening, not as a knockout pill at bedtime. Physiologic doses (~0.3–1 mg) match natural levels; common 5–10 mg gummies are far supraphysiologic.

What the studies show →

Meta-analyses show melatonin modestly shortens sleep latency and is most effective for circadian-phase problems; timing and low dose matter more than amount. It's not a first-line treatment for chronic insomnia (CBT-I is).

The short list with the most support

  • Magnesium (glycinate/threonate) — best if you're low; supports relaxation, gentle evidence.
  • Glycine (~3 g before bed) — small studies show improved subjective sleep quality and faster onset.
  • L-theanine (~100–200 mg) — promotes calm without sedation; pairs well with winding down.
  • Apigenin (from chamomile) — mild, popular in stacks; evidence is preliminary.
  • Melatonin (0.5–1 mg, early) — for circadian shifting/jet lag, not nightly sedation.
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Go deeper in the Supplements program

Learn how to read doses, forms, and evidence so you can judge any sleep supplement for yourself.

Check yourself

What's the most accurate way to think about melatonin?

  1. A strong sedative — more milligrams means deeper sleep
  2. A timing signal — a small, well-timed dose shifts your clock
  3. A vitamin you should take nightly for life
  4. Useless in every situation
Show the answer →

B.A timing signal — a small, well-timed dose shifts your clock

Melatonin is a chronobiotic: a small dose (0.5–1 mg) taken in the early evening nudges your circadian clock. Bigger doses aren't better and can cause grogginess.