Sleep

The best supplements for sleep, matched to your kind of bad night.

Q: How much melatonin should I take for sleep?

Start with 0.5–1 mg, 30–60 minutes before bed; more is not better. To move a late body clock earlier, 0.5 mg is taken hours before bedtime instead. Buy a third-party-tested product: in one analysis, melatonin supplements held anywhere from 83% less to 478% more than their labels said.

Q: How long does ashwagandha take to work for sleep?

Plan on 8 weeks or more. In the trials, effects were larger at 600 mg a day and after at least 8 weeks, and cortisol fell by about a quarter after 60 days. Take it in the evening, in 8–12-week cycles, and judge it on your own data, not a few nights.

Q: What is the best supplement for deep sleep?

Glycine has the most direct data: in small sleep-lab studies, 3 g before bed helped people reach deep sleep about 10 minutes sooner. The bigger lever is often subtraction: caffeine taken too late cost about 11 minutes of deep sleep in a 24-study meta-analysis, so check your cut-off first.

Slow to drop off, awake at 3 a.m. or short on hours: each has a different best pick. Here is what the trials found, in minutes.

By the Umbral teamUpdated October 3, 20269 min read49 studies cited

Quick answer

The best-evidenced supplements for sleep are ashwagandha, saffron and melatonin. Ashwagandha improved sleep across 5 trials, saffron improved sleep-quality scores across 8 trials, and melatonin helps you fall asleep about 7 minutes sooner. Tart cherry, magnesium and glycine are moderate-grade picks for short nights and slow sleep onset. The right one depends on how you sleep badly.

Key takeaways

Match the supplement to the problem: melatonin for a shifted body clock, magnesium or glycine for slow sleep onset, ashwagandha for night waking, tart cherry for short nights.
Ashwagandha and saffron pair strong grades with effects large enough to see, and both take weeks: 8 or more for ashwagandha, 1–4 for saffron.
Melatonin works, but only a little: about 7 minutes faster sleep onset, too small for a wearable to see.
Late caffeine costs about 45 minutes of sleep; stop coffee 8.8 hours before bed.
Insomnia past 3 months, loud snoring with pauses in breathing or SpO₂ under 92% go to a clinician, not to a supplement.

In this guide

What is the best supplement for sleep?
Which sleep supplement is best for you?
Do sleep supplements actually work?
Melatonin or magnesium: which is better for sleep?
Which magnesium is best for sleep?
Which supplements make sleep worse?
What about valerian and GABA?
Will your wearable show the difference?
Frequently asked questions
References

What is the best supplement for sleep?

On the evidence, ashwagandhaStrong: across 5 trials it improved sleep, including measured sleep efficiency and night waking, by enough to show in your own data after 8 or more weeks. SaffronStrong is a close second. MelatoninStrong has strong evidence for a small effect, best kept for body-clock problems.

The best sleep supplements, ranked by evidence and effect size
Supplement · Evidence	Best for	What studies found	Typical dose	On your wearable
Ashwagandha Strong	Stress-linked sleep and night waking	Better sleep in 5 trials, including measured efficiency and night waking.	600 mg/day	Likely visible
Saffron (Crocus sativus extract) Strong	Poor sleep quality, especially with low mood	Sleep-quality score about 2 points better across 8 trials.	28–30 mg/day of extract	Likely visible
Melatonin Strong	Jet lag, shift work, a late body clock	About 7 minutes faster sleep onset across 19 trials.	0.5–1 mg, start low	Below wearable noise
Tart cherry Moderate	Short nights	About 34 more minutes of sleep a night within 7 days; small trials.	2 × 1 fl oz (30 mL) concentrate	Likely visible
Magnesium Moderate	Slow sleep onset, low-magnesium diet	About 17 minutes faster sleep onset in older adults with insomnia.	200–400 mg elemental	Below wearable noise
Glycine Moderate	Slow sleep onset, warm nights	Reached deep sleep about 10 minutes sooner in small studies.	3 g before bed	Below wearable noise
L-theanine Moderate	A busy mind, without sedation	Faster sleep onset in stressed adults after 4 weeks at 200 mg.	200 mg	Below wearable noise

The order weighs grade and effect size. Tier A means the effect is plausibly visible in your own trend; tier B means real, but usually below night-to-night noise. Silexan lavender oilStrong earns its strong grade in anxiety trials, not sleep trials, so it sits with the calming options further down.

Which sleep supplement is best for you?

The one that matches how you sleep badly. Slow sleep onset, waking at night, short nights, a shifted body clock and stress each have a different best-evidenced pick, and good sleepers need none. Find your row, start with one supplement, and give it the time the trials did.

Which sleep supplement fits your kind of bad night
If this sounds like you	Start with	Why
You lie awake long before you drop off	MagnesiumModerate or glycineModerate	Magnesium cut sleep onset by about 17 minutes in older adults with insomnia; glycine speeds onset and deep sleep.
You fall asleep fine but wake in the night	AshwagandhaStrong	The best evidence among supplements to stay asleep: less time awake in objective trials, after 8+ weeks.
Your nights are too short	Tart cherryModerate	About 34 more minutes a night within 7 days, in a small trial.
Jet lag, a late body clock or shift work	MelatoninStrong	A timing signal, not a sedative: 0.5 mg taken hours before bed moves a late clock earlier.
Stress or a racing mind keeps you up	L-theanineModerate or Silexan lavender oilStrong	Neither sedates; lavender's sleep gains come through easing anxiety.
Poor sleep, and your mood dips with it	SaffronStrong	Sleep-quality scores improved across 8 trials; low mood alongside is its best fit.
You already sleep well	Nothing	Ashwagandha did little in good sleepers, and small effects won't stand out in your data.

If stress is at the root, the guide to supplements for stress covers the daytime side.

Do sleep supplements actually work?

Some do, by modest amounts you can measure. AshwagandhaStrong and saffronStrong have strong grades and effects large enough for a wearable trend, and tart cherryModerate showed big gains in small trials. Others change how people rate their sleep more than how long or how well they actually sleep.

Ashwagandha

Strong

Root extract (KSM-66 / Shoden)

Suits stress-linked sleep and night waking. In the 3 trials that measured sleep objectively, people fell asleep faster, woke less and spent more of their time in bed asleep; cortisol fell by about a quarter at 600 mg.

Judge it at 8 weeks, not 8 nights. Tier A: sleep efficiency and time awake can show in your trend.

Dose: 600 mg/day (or 300 mg ×2)
Timing: Evening; benefits build over 8+ weeks. Cycle 8–12 weeks.

Watch out for

· Rare liver-injury case reports (NIH LiverTox) — stop on dark urine/jaundice.
· Raises thyroid hormones — avoid with hyperthyroidism or levothyroxine.
· Avoid in pregnancy and autoimmune disease.

Likely visibleSee the full evidence →

Saffron (Crocus sativus extract)

Strong

affron® standardised saffron extract, 28 mg/day (≥3.5% Lepticrosalides®); Safr'Inside™ 30 mg/day is the alternative with objective-sleep data

Suits poor sleep quality, especially with low mood. Across 8 trials and 611 people, a sleep-quality score improved about 2 points and an insomnia-severity score fell. In a 2025 EEG pilot, older adults took 21% less time to fall asleep; total sleep did not change. Tier A, over 1–4 weeks.

Dose: 28–30 mg/day of standardised extract (14 mg twice daily or 28 mg once); 20 mg/day also effective in the 2025 insomnia trial
Timing: Single evening dose about 1 hour before bed; effects build over 1–4 weeks

Watch out for

· Avoid in pregnancy: doses well above supplemental levels are uterotonic and abortifacient.
· Contraindicated in bleeding disorders; saffron inhibits platelet aggregation in vitro.
· Doses of 5 g are toxic (purpura, thrombocytopenia); supplement doses of 28–100 mg are far below this.

Likely visibleSee the full evidence →

Tart cherry

Moderate

Montmorency concentrate or powder

Suits short nights. In a 7-day trial of 20 people, Montmorency tart cherry added about 34 minutes of sleep and 5–6% sleep efficiency; a pilot in 8 older adults with insomnia found 84 minutes. Small studies, so expect less. Tier A. Juice carries sugar; prefer concentrate or capsules.

Dose: 2 × 30 mL (1 fl oz) concentrate or ~480 mg powder
Timing: Morning + 1–2 h before bed

Watch out for

· Benign; note sugar content in juice.

Likely visibleSee the full evidence →

Glycine

Moderate

Powder

Suits slow sleep onset and warm nights. It lowers core body temperature slightly, the cue your body uses to start sleep; in small sleep-lab studies people fell asleep about 5 minutes faster and reached deep sleep about 10 minutes sooner. One research group, tier B.

Dose: 3 g
Timing: 30–60 min before bed

Watch out for

· Very benign; occasional mild GI upset.

Below wearable noiseSee the full evidence →

Calming options for a busy mind

L-theanineModerate: 200 mg a day for 4 weeks shortened sleep onset in stressed adults, without sedation. One sleep trial so far; tier B.
Silexan lavender oilStrong: at 80 mg a day, an anxiety rating fell 2.8 points more than placebo in a 10-week trial of 539 people, and in one analysis 98.4% of its sleep benefit ran through easing anxiety. It fits only if anxiety keeps you up. Tier B.
ApigeninEmerging: the evidence is chamomile extract; isolated 50 mg capsules have no sleep trial. Across 5 trials, sleep-quality ratings improved about 2 points, but efficiency and duration did not. Tier B.
Lemon balmModerate: eased anxiety by a large margin in several trials, but its sleep evidence rests mostly on one trial whose large effect still needs replication. Tier B.

Melatonin or magnesium: which is better for sleep?

It depends on the problem. MelatoninStrong is a timing signal: across 19 trials it helped people fall asleep about 7 minutes sooner, and it does most for jet lag, a late body clock and shift work. MagnesiumModerate cut sleep onset by about 17 minutes in older adults with insomnia, most in people who get little magnesium from food.

Melatonin

Strong

Low dose, USP-verified

It signals biological night rather than sedating you, so it works best when the clock is the problem. For everyday insomnia, your wearable's sleep-onset reading swings by about 20 minutes from night to night, and a 7-minute gain disappears inside that. Tier B.

Dose: 0.5–1 mg (start low)
Timing: 30–60 min before bed; 0.5 mg hours earlier to advance a late chronotype

Watch out for

· Label accuracy problem (−83% to +478% of stated dose) — choose third-party-tested.
· Interacts with anticoagulants, contraceptives, immunosuppressants.

Below wearable noiseSee the full evidence →

Magnesium

Moderate

Glycinate or citrate (not oxide)

A cheap, safe bet if your diet is low in magnesium, probably a placebo if not. The 17 minutes come from 3 small trials in 151 older adults, rated low quality by their own authors; total sleep did not change significantly. Tier B.

Dose: 200–400 mg elemental
Timing: 1–2 h before bed

Watch out for

· Diarrhea at higher doses (form-dependent).
· Caution in kidney disease.

Below wearable noiseSee the full evidence →

A clock problem points to melatonin; slow settling on a normal schedule points to magnesium. Taking both from night one hides which did the work.

Which magnesium is best for sleep?

Magnesium glycinateModerate or magnesium citrate, not magnesium oxide. Those are the forms we recommend for sleep, and the 2025 trials that improved how people rated their sleep used bisglycinate. Dose by elemental magnesium, 200–400 mg, taken 1–2 hours before bed, and expect the most if your diet is low in magnesium.

Check the label for elemental magnesium, not the weight of the whole compound. Diarrhea at higher doses depends on the form; with kidney disease, ask a clinician first.

Which supplements make sleep worse?

Late caffeineStrong is the big one. In a 24-study meta-analysis, caffeine taken too late cost about 45 minutes of total sleep and 11 minutes of deep sleep, and added 9 minutes to falling asleep. A 107 mg coffee needs at least 8.8 hours before bed; a 217 mg pre-workout needs 13.2 hours.

For an 11 pm bedtime, that puts your last coffee at about 2 pm and your last pre-workout at about 10 am. Your wearable will show this one (tier A). Caffeine's performance side is in the guide to supplements for training.

Panax ginsengModerate: insomnia is a documented side effect. Morning and midday only, never evening.
PhosphatidylserineEmerging: insomnia is reported above 300 mg a day. Split it between breakfast and lunch.
Cocoa flavanolsModerate: the extract carries caffeine and theobromine. Morning and midday.
RhodiolaEmerging: mildly stimulating. Morning only.

Check when you take these; moving a dose earlier costs nothing.

What about valerian and GABA?

We leave both out. Valerian, one of the best-known natural sleep aids, improved how people rated their sleep but produced no objective change on actigraphy. Oral GABA has doubtful passage across the blood-brain barrier and only low-quality evidence. A better night you feel but no instrument records is not something your wearable can confirm.

Kava, sold for relaxation, is out for a different reason: liver-toxicity reports, and bans or warnings in several countries. For calm, L-theanineModerate and Silexan lavender oilStrong have better evidence.

Will your wearable show the difference?

For some, yes. AshwagandhaStrong, saffronStrong and tart cherryModerate move sleep by enough to show in your own trend over weeks. MelatoninStrong, magnesiumModerate, glycineModerate and the calming options have real effects that usually sit below night-to-night noise. Late caffeineStrong shows up clearly, in the wrong direction.

01Connect the wearable you already own (WHOOP, Oura, Garmin or Apple Watch) and let it learn your band, your normal range.
02Start one supplement from the table above; keep your bedtime and caffeine cut-off steady.
03Give it the trial's time: 7 days for tart cherry, 1–4 weeks for saffron, 8+ weeks for ashwagandha.
04Watch its target metric: sleep onset for magnesium and glycine, total sleep for tart cherry, efficiency and time awake for ashwagandha.
05Read the result against your band: a sustained shift is an association, not proof of cause.

That is what Umbral is built for: nothing new to buy, one supplement backed by scientific evidence, and an answer measured against your own band. For everything beyond sleep, see which supplements you actually need.

Frequently asked questions

How much melatonin should I take for sleep?

Start with 0.5–1 mg, 30–60 minutes before bed; more is not better. To move a late body clock earlier, 0.5 mg is taken hours before bedtime instead. Buy a third-party-tested product: in one analysis, melatonin supplements held anywhere from 83% less to 478% more than their labels said.

Can I take magnesium and melatonin together?

No trial in the evidence we grade has tested the combination, so there is no data that they add up. Start one at a time and give it a few weeks before adding the other; otherwise you won't know which one worked. Melatonin also interacts with anticoagulants, contraceptives and immunosuppressants.

How long does ashwagandha take to work for sleep?

Plan on 8 weeks or more. In the trials, effects were larger at 600 mg a day and after at least 8 weeks, and cortisol fell by about a quarter after 60 days. Take it in the evening, in 8–12-week cycles, and judge it on your own data, not a few nights.

Is it safe to take sleep supplements every night?

Most of these are taken nightly, but each has limits. Ashwagandha runs in 8–12-week cycles; stop it if you notice dark urine or yellowing skin. Melatonin labels are unreliable, so buy third-party-tested. Ashwagandha, saffron and chamomile are ones to avoid in pregnancy, and medications are worth checking with a clinician.

What is the best supplement for deep sleep?

Glycine has the most direct data: in small sleep-lab studies, 3 g before bed helped people reach deep sleep about 10 minutes sooner. The bigger lever is often subtraction: caffeine taken too late cost about 11 minutes of deep sleep in a 24-study meta-analysis, so check your cut-off first.

Does tart cherry juice help you sleep?

It may. In one small trial, Montmorency tart cherry added about 34 minutes of sleep a night within 7 days, and a pilot in older adults with insomnia found 84 minutes. The studies were small, so expect less. Juice carries sugar; concentrate or capsules are the cleaner choice.

Find out which of these move your numbers.

A guide can rank the evidence; only your own data can say what works for you. Umbral learns your band (your normal range) for sleep, HRV and recovery, recommends the supplements with evidence for what it sees, and measures each one against you. Results read as association, not causation.

Find out which supplements you need

Just connect the wearable you already own: WHOOP, Oura, Garmin, Fitbit and more. Nothing new to buy, no blood draw to start.

References

Every number in this guide comes from these studies: the same evidence catalogue that grades recommendations inside Umbral.

Rhodiola rosea

Rhodiola rosea for physical and mental fatigue: a systematic review
BMC Complementary and Alternative Medicine · 2012 · systematic review

Umbral is a wellness product, not a medical device. It does not diagnose, treat, cure or prevent any disease. Supplement information is educational; talk to a clinician before starting anything, especially if you are pregnant, under 18, managing a condition or taking medication. These statements have not been evaluated by the Food and Drug Administration.

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