Sleep Duration
Can supplements add meaningful sleep time? Here is how trial results compare with the broader task of treating poor sleep.
What is being measured?
Total sleep time measures how long someone sleeps. In melatonin trials, self-reported improvements have differed from results obtained with objective sleep measurements. 1
Why can sleep become difficult?
Stress, anxiety, and unhelpful sleep habits can contribute to sleep problems. A medical conversation can also identify physical or psychological causes. 2
What can help beyond a supplement?
Cognitive behavioral therapy addresses thoughts and behaviors that keep sleep difficulties going. Relaxation and changes in sleep habits are other options discussed in German patient guidance. 2
What should you know about safety?
Melatonin appears relatively safe for short-term use, but long-term safety is not established. NCCIH also reports inaccurate labeling of some products and overdose risks for children. 3
Nutrients with the strongest ratings
Sorted by the largest rated effect. Bars show effect size, the letter is the evidence grade.
Every ratingEvery nutrient rated for sleep duration, with search
What does the evidence cover?
This section covers the specific uses below; other supplements are not reviewed.
MelatoninMixedA 2013 analysis of 19 studies found about eight extra minutes of sleep in its main model. The improvement was not significant when only objective measurements were considered or when a different pooling model was used. 1
Melatonin: why timing mattersMixedA 2024 analysis of 26 adult trials found that dose and timing influenced sleep outcomes. Its model-based suggestions are research findings, not an individual dosing plan. NCCIH notes that guidelines have recommended against melatonin for chronic insomnia. 3 4
Questions people ask
Does falling asleep faster mean sleeping longer?
They are separate outcomes and may respond differently in trials. 1
How large was the average melatonin benefit?
The 2013 analysis reported about seven minutes faster sleep onset and eight minutes longer total sleep; the duration result depended on the analysis used. 1
Is glycine well established?
The review identified small sleep studies with high risk of bias. 5
Is long-term melatonin safety settled?
No. NCCIH says long-term safety has not been established. 3
What is cognitive behavioral therapy for sleep?
It helps change thoughts and behaviors that interfere with sleep. 2