Supplements for each part of sleep, graded by evidence (REM, deep, latency, staying asleep)
Research and education, not medical advice.
I’ve been compiling research on what influences different metrics wearables track for about 9 months now. I realized I had a list of supplement research that could make an interesting breakdown of what supplements influence different stages/parts of sleep (this is not medical advice of course).
Sources are linked in each table, any funding worth mentioning is flagged, and there is a short plain english read on each study to make your own digging a bit easier. I broke grades by: Strong is a meta or several RCTs. Moderate is one solid RCT. No effect is a well tested null.
If you find the tables are too difficult on mobile I make it into mobile friendly page which I’ll include in the comments (this is a website I own).
Staying asleep (WASO)
| Supplement | effect | source | plain english |
|---|---|---|---|
| Ashwagandha | Less waking | Strong, meta SMD -0.39, n=281 (Cheah 2021, industry-funded) | The strongest supplement evidence for cutting nighttime waking |
| Tart Cherry | Less waking | Moderate, n=15, -17 min (Pigeon 2010) | Cut nighttime waking vs placebo in an insomnia group |
| Glycine | Less waking | Moderate, n=11 (Yamadera 2007) | Reduced waking and deepened sleep in the same PSG study |
| Melatonin (immediate release) | No effect | Strong null (Moon 2022) | The most bought form does not help you stay asleep, only fall asleep |
Deep Sleep (N3)
| Supplement | effect | source | plain english |
|---|---|---|---|
| Magnesium L-threonate | Positive | Moderate, Oura RCTs (Hausenblas/Breus 2024, manufacturer-funded) | Improved Oura tracked deep sleep in 2 of 3 trials. One found no objective change |
| Glycine | Faster into deep | Moderate, n=11 (Yamadera 2007) | Gets you into deep sleep faster without changing the total |
| Melatonin | Positive (delta) | Moderate, mechanism (Comai 2024) | Raises deep sleep delta waves but its main job is timing not deep sleep |
| Omega-3 (DHA) | Efficiency | Moderate, n=84, 26 wks (PMC7830450) | Improved overall efficiency. No isolated N3 gain |
Falling asleep faster (sleep latency)
| Supplement | effect | source | plain english |
|---|---|---|---|
| Melatonin | Faster | Strong, meta 19 studies, n=1,683, -7.06 min (Ferracioli-Oda 2013) | Cuts about 7 min off sleep onset. A timing aid not a sedative |
| Ashwagandha | Faster | Strong, meta 5 RCTs, n=400, SMD -0.53 (Cheah 2021, industry-funded) | Shortens onset, strongest in insomnia |
| Magnesium | Faster | Moderate, meta 3 RCTs, n=151, -17.36 min (Mah & Pitre 2021) | About 17 min faster in older adults but graded low quality |
| Glycine | Faster | Moderate, PSG, n=11 (Yamadera 2007) | Before bed helped people fall asleep and reach deep sleep sooner |
| GABA | Faster | Moderate, RCT, n=40 (Byun 2018) | Cut onset from 13.4 to 5.7 min. Note that GABA is poorly absorbed orally |
| L-Theanine | Subjective only | Moderate, meta, n=897 (Bulman 2025) | People feel like they fall asleep faster but devices did not confirm it |
REM sleep
| Supplement | effect | source | plain english |
|---|---|---|---|
| Melatonin | Positive (if your REM started low) | 2 RCTs, n=14 (Kunz 2004) | Nudged REM up but only in people whose REM was well below normal and the trials were tiny. |
| 5-HTP | Positive (small, clinical) | RCT, n=18 Parkinson’s, 50 mg, 4 wks (Sleep and Breathing 2021) | It feeds serotonin and melatonin just not confirmed in healthy sleepers |
| Vitamin B6 | Dream recall, not REM time | pilot + larger study (Ebben 2002 / Aspy 2018) | Makes dreams more vivid and easier to recall, which feels like more REM but it did not add REM time |
If I missed one you think should be added lmk and I’ll add it once I verify a credible source. Hope you enjoy!
Archived into the Nootopics wiki from r/NooTopics — originally posted by u/KygoApp on 2026-06-24. Curated, not authored by the community.
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