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Sleep

Melatonin

Low dose, USP-verified

StrongReal effect, but below wearable noise
2
sources
19
trials
1,683
participants (largest study)
2
study designs
The verdict

Melatonin reliably helps people fall asleep a little sooner — about seven minutes in the benchmark meta-analysis — and adds around eight minutes of sleep. The effect is real, but smaller than the night-to-night variation your wearable already shows, so don't expect your sleep score to move. Where it shines is shifting your body clock: jet lag, late chronotypes, shift work.

Why this grade
Emerging
Preliminary or mechanistic
Moderate
Some RCTs, limited replication
Strong
Multiple RCTs or meta-analyses, consistent direction

Strong for sleep onset: 19 RCTs, n = 1,683, consistent direction, dose-response established. Marked Tier B for wearables because a 7-minute shift sits inside sensor noise.

How it works

Signals 'biological night' to the suprachiasmatic nucleus via MT1/MT2 receptors — a timing cue rather than a sedative.

Who it helps, and who it doesn't

Circadian problems (jet lag, delayed sleep phase, shift work). Start at 0.5–1 mg; more is not better. Choose third-party-tested products — measured content ranged from −83% to +478% of the label.

Measured effects (absolute, from the trials)

Every estimate, against a line of no effect

Diamonds are point estimates; the hairline is the 95% confidence interval where the trial reported one.

  • Sleep onset latency
    min · Ferracioli-Oda 2013
    −7.06
    −8.98 … −5.13
  • Total sleep time
    min · Ferracioli-Oda 2013
    +8.25
    +1.74 … +14.8
−100+10NO EFFECT

Units are never mixed on one line: each scale gets its own axis. Where a trial reported no confidence interval we leave it blank rather than inventing one.

Will you see it in your wearable?

We compare each effect to the typical night-to-night noise of that metric. Effects smaller than the noise are real but invisible in a week of data.

  • Sleep onset latencyVisible over weeks
    effect: 7.06 minnightly noise: ±20 min
  • Total sleep timeBelow noise
    effect: 8.25 minnightly noise: ±50 min
Studies over time

2 studies across 4 years

2013 — 2017
20132014201520162017
Meta-analysis or systematic reviewRandomized or crossover trialObservational or preliminaryHover a marker for detail
Dose
0.5–1 mg (start low)
Timing
30–60 min before bed; 0.5 mg hours earlier to advance a late chronotype
Safety flags
  • · Label accuracy problem (−83% to +478% of stated dose) — choose third-party-tested.
  • · Interacts with anticoagulants, contraceptives, immunosuppressants.
Where to buyRecord what I'm taking

References

  1. 1.
    Meta-analysis: melatonin for the treatment of primary sleep disorders
    PLOS ONE · 2013 · meta-analysis · 19 trials · n = 1,683

    Sleep onset −7.06 min, total sleep +8.25 min, modest subjective quality gain.

  2. 2.
    Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content
    Journal of Clinical Sleep Medicine · 2017 · cohort · n = 31

    Content ranged from −83% to +478% of label; 26% contained serotonin.

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.