Sleep
Supplements studied for sleep.
Overview
Several supplements have moderate evidence for sleep improvement. Valerian (7 studies) is rated possibly effective. Ashwagandha (6 studies) may modestly improve sleep onset, duration, and quality at doses of 120–600 mg daily over 6–12 weeks, with stronger effects at higher doses in people with insomnia.
Glycine (4 studies) at 3 grams before bed may improve sleep quality over a few days. L-Theanine (6 studies) has unclear standalone benefit. Vitamin D (1 study) improved sleep quality in adults with sleep problems. See the heatmap and evidence reviews below.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Valerian | ★★★★★ | Medium |
| Ashwagandha | ★★★★★ | Medium |
| Theanine | ★★★★★ | Medium |
| Vitamin D | ★★★★★ | Medium |
| Glycine | ★★★★★ | Low |
| GABA | ★★★★★ | Low |
| Vitamin B6 | ★★★★★ | Low |
| Probiotics | ★★★★★ | Low |
| Quercetin | ★★★★★ | Very Low / None |
| Apigenin | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
10 supplements for , and rated at least stars. All purchase bands. No minimum star filter.
AshwagandhaView supplement →
Consider purchase·★★★★★
How we scored this▸
- Taking ashwagandha by mouth can modestly improve sleep for people with insomnia or poor-quality sleep.
- Studies show that using specific types of ashwagandha in doses from about 120 mg up to 600 mg daily for 6 to 12 weeks helps improve how long it takes to fall asleep, total sleep time, and overall sleep quality compared to no treatment.
- The benefits seem more evident with doses of least 600 mg daily for 8 weeks or longer, especially in people with insomnia.
- Some studies also tested ashwagandha combined with tryptophan or in special milk drinks and found these may help too, but more research is needed.
Browse 6 studies·2 meta-analyses
RCTEffectiveness of Enriched Milk with Ashwagandha Extract and Tryptophan for Improving Subjective Sleep Quality in Adults with Sleep Problems: A Randomized Double-Blind Controlled Trial2024n=13
In 52 adults with sleep problems over 90 days, milk enriched with ashwagandha 250–600 mg improved sleep VAS versus control, without clear added benefit from combining tryptophan.
- Effect
- Benefit
- Duration
- 90 days
- Dose
- 250–600 mg/day
- Population
- Healthy adults
- Participants
- 13
- Ages
- 18+
MetaSafety and efficacy of Withania somnifera for anxiety and insomnia: Systematic review and meta-analysis2024n=254
A meta-analysis of 5 RCTs (254 participants) found ashwagandha significantly reduced Hamilton Anxiety Scale scores and improved sleep latency, total sleep time, PSQI, and sleep efficiency versus placebo.
- Effect
- Benefit
- Population
- Adults
- Participants
- 254
MetaEffect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis2021n=400
A meta-analysis of 5 studies including 400 participants found that ashwagandha exhibited a small but significant benefit for overall sleep quality. Ashwagandha significantly improved anxiety and alertness on waking but not quality of life. Greater benefits were seen in the subgroup of adults diagnosed with insomnia, using treatment dosages ≥ 600 mg/day for ≥8 weeks.
- Effect
- Benefit
- Dose
- 600 mg/day
- Population
- Adults
- Participants
- 400
RCTA randomized, double blind, placebo controlled study to evaluate the effects of ashwagandha (Withania somnifera) extract on sleep quality in healthy adults2020n=144
In 150 adults with non-restorative sleep, ashwagandha 120 mg/day (Shoden) for 6 weeks improved sleep quality, sleep efficiency, total sleep time, and quality of life versus placebo.
- Effect
- Benefit
- Duration
- 6 weeks
- Dose
- 120 mg/day
- Population
- Healthy adults
- Participants
- 144
RCTEfficacy and Tolerability of Ashwagandha Root Extract in the Elderly for Improvement of General Well-being and Sleep: A Prospective, Randomized, Double-blind, Placebo-controlled Study2020n=25
In elderly adults aged 65–80 over 12 weeks, ashwagandha 600 mg/day improved WHOQOL scores, sleep quality, and mental alertness versus placebo.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 600 mg/day
- Population
- Older adults
- Participants
- 25
- Ages
- 65–80
RCTEfficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-blind, Randomized, Placebo-controlled Study2019n=58
In 58 adults with insomnia and anxiety over 10 weeks, ashwagandha 300 mg twice daily improved sleep onset latency, efficiency, PSQI, and HAM-A anxiety scores versus placebo.
- Effect
- Benefit
- Duration
- 10 weeks
- Dose
- 600 mg/day
- Population
- Adults
- Participants
- 58
- Ages
- 18–60
ValerianView supplement →
Consider purchase·★★★★★
How we scored this▸
- Valerian is possibly effective for Sleep.
Browse 7 studies·1 meta-analysis
RCTEffects of a Valerian-Hops Extract Combination (Ze 91019) on Sleep Duration and Daytime Cognitive and Psychological Parameters in Occasional Insomnia: A Randomized Controlled Feasibility Trial2025n=40
An RCT of 40 adults with occasional insomnia found that valerian-hops extract (Ze 91019) for 21 days increased sleep duration by 21.7 min/day versus placebo without affecting daytime cognition.
- Effect
- Benefit
- Duration
- 21 days
- Population
- Adults
- Participants
- 40
RCTStandardized Extract of Valeriana officinalis Improves Overall Sleep Quality in Human Subjects with Sleep Complaints: A Randomized, Double-Blind, Placebo-Controlled, Clinical Study2024n=37
An RCT of 72 adults with sleep complaints found that standardized valerian extract for 8 weeks significantly improved PSQI scores, sleep latency, sleep efficiency, and total sleep time versus placebo.
- Effect
- Benefit
- Duration
- 8 weeks
- Population
- Adults
- Participants
- 37
RCTEffect of Fennel-Valerian Extract on Hot Flashes and Sleep Disorders in Postmenopausal Women: A Randomized Trial2023
A randomized trial of 76 postmenopausal women (ages 45–55) found that fennel-valerian extract 1000 mg/day for 8 weeks reduced sleep disorders and the severity and frequency of hot flashes versus placebo.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 1000 mg/day
- Population
- Postmenopausal women
- Ages
- 45–55
RCTThe Effects of Valerian on Sleep Quality, Depression, and State Anxiety in Hemodialysis Patients: A Randomized, Double-blind, Crossover Clinical Trial2021n=20
A crossover RCT of 39 hemodialysis patients found that valerian significantly improved sleep quality, state anxiety, and depression scores versus placebo over two 1-month treatment periods.
- Effect
- Benefit
- Duration
- 1 month
- Population
- Hemodialysis patients
- Participants
- 20
RCTEffect of valerian on sleep quality in postmenopausal women: a randomized placebo-controlled clinical trial2011
A triple-blind RCT of 100 postmenopausal women (ages 50–60) found valerian 530 mg twice daily for 4 weeks improved sleep quality in 30% versus 4% on placebo (P<0.001).
- Effect
- Benefit
- Duration
- 4 weeks
- Dose
- 1060 mg/day
- Population
- Postmenopausal women
- Ages
- 50–60
RCTThe use of Valeriana officinalis (Valerian) in improving sleep in patients who are undergoing treatment for cancer: a phase III randomized, placebo-controlled, double-blind study (NCCTG Trial, N01C5)2011n=227
A phase III RCT of 227 cancer patients found valerian 450 mg nightly for 8 weeks did not improve PSQI sleep scores versus placebo, though exploratory analyses showed fatigue improvements.
- Effect
- No Benefit
- Duration
- 8 weeks
- Dose
- 450 mg valerian
- Population
- Cancer patients
- Participants
- 227
MetaValerian for sleep: a systematic review and meta-analysis2006n=1,093
A systematic review of 16 trials (1,093 adults) found valerian may improve subjective sleep quality (RR 1.8, 95% CI 1.2–2.9), though most studies had methodologic limitations.
- Effect
- Benefit
- Population
- Adults
- Participants
- 1,093
TheanineView supplement →
Consider purchase·★★★★★
How we scored this▸
- It is unclear if taking L-theanine by mouth helps with sleep.
- One small study found that a 50 mg dose before bed helped reduce waking up caused by caffeine but did not improve falling asleep or total sleep time.
- L-theanine combined with other ingredients has sometimes improved sleep length, quality, and daytime tiredness in small studies, but it is not known if these effects are from L-theanine or the other ingredients.
Browse 6 studies
RCTNutritional Modulation of Sleep Latency, Duration, and Efficiency: A Randomized, Repeated-Measures, Double-Blind Deception Study2023n=9
In a crossover RCT of 16 adults, a nutritional blend with glycine, tryptophan, magnesium, and tart cherry improved self-reported sleep quality versus placebo.
- Effect
- Benefit
- Population
- Healthy adults
- Participants
- 9
- Avg age
- 24±3
RCTTheanine maintains sleep quality in healthy young women by suppressing the increase in caffeine-induced wakefulness after sleep onset2023
A crossover study found that theanine (50 mg) suppressed caffeine-induced wakefulness after sleep onset, maintaining sleep quality in healthy young women.
- Effect
- Benefit
- Dose
- 50 mg
- Population
- Women
RCTCombining Topical and Oral Botanicals for Skin Redness, Pigmentation, Sleep, and Mood: A Randomized Controlled Study2022n=75
An RCT of 75 women found that oral botanicals including L-theanine improved sleep quality at 1 and 8 weeks and reduced facial redness at 8 weeks versus topical-only treatment.
- Effect
- Benefit
- Population
- Women
- Participants
- 75
- Ages
- 18–55
RCTEffect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial2022n=39
A crossover RCT of 39 adults found that alpha-s1-casein hydrolysate plus L-theanine (RLX2) for 4 weeks improved PSQI scores and prolonged total sleep time by 45 minutes versus placebo.
- Effect
- Benefit
- Duration
- 4 weeks
- Population
- Adults
- Participants
- 39
RCTEffects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial2019n=30
An RCT of 30 healthy adults found that 200 mg/day L-theanine for 4 weeks significantly reduced trait anxiety, depression, and PSQI sleep scores and improved verbal fluency versus placebo.
- Effect
- Benefit
- Duration
- 4 weeks
- Dose
- 200 mg/day
- Population
- Healthy adults
- Participants
- 30
- Avg age
- 48.3±11.9
RCTThe effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial2011n=98
An RCT of 98 boys with ADHD found that 400 mg/day L-theanine for 6 weeks significantly improved sleep percentage and sleep efficiency on actigraphy versus placebo.
- Effect
- Benefit
- Duration
- 6 weeks
- Dose
- 400 mg/day
- Population
- Children/adolescents
- Participants
- 98
- Ages
- 8–12
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- A clinical study in adults aged 20 to 50 with sleep problems found that taking vitamin D supplements (50,000 IU every two weeks for 8 weeks) helped improve sleep quality compared to taking a placebo.
- People who took vitamin D fell asleep faster, slept longer, and felt their sleep was better.
- These improvements were statistically significant even after accounting for other factors.
Browse 1 study
RCTThe effect of vitamin D supplement on the score and quality of sleep in 20-50 year-old people with sleep disorders compared with control group2017n=89
An 8-week RCT in 89 adults aged 20–50 with sleep disorders found vitamin D 50,000 IU fortnightly improved sleep quality scores versus placebo.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 50000 IU/day
- Population
- Adults
- Participants
- 89
- Ages
- 20–50
GABAView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- GABA supplements might help some people fall asleep a little faster, but they do not seem to improve sleep quality in a reliable way.
- Most of the positive research is small and industry funded.
Browse 3 studies
RCTEfficacy and Safety of Low-Dose Gamma-Aminobutyric Acid From Unpolished Rice Germ as a Health Functional Food for Promoting Sleep: A Randomized, Double-Blind, Placebo-Controlled Trial2022n=54
In a 4-week double-blind RCT of 54 adults, 75 mg/day GABA from unpolished rice germ improved sleep quality versus placebo as a health functional food.
- Effect
- No Benefit
- Duration
- 4 weeks
- Dose
- 75 mg/day
- Population
- Adults
- Participants
- 54
RCTSafety and Efficacy of Gamma-Aminobutyric Acid from Fermented Rice Germ in Patients with Insomnia Symptoms: A Randomized, Double-Blind Trial2018n=30
In a 4-week double-blind RCT of 40 insomnia patients, 300 mg/day GABA from fermented rice germ reduced sleep latency and increased sleep efficiency versus placebo on polysomnography.
- Effect
- Benefit
- Duration
- 4 weeks
- Dose
- 300 mg/day
- Population
- Adults
- Participants
- 30
- Ages
- 18+
RCTEffect of oral γ-aminobutyric acid (GABA) administration on sleep and its absorption in humans2016n=10
In a crossover study of healthy adults, oral GABA shortened sleep latency and increased non-REM sleep time on EEG; blood GABA peaked 30 minutes after dosing.
- Effect
- Benefit
- Population
- Healthy adults
- Participants
- 10
GlycineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taking 3 grams of glycine before bed for a few days may help improve sleep quality in people who have trouble sleeping or do not get enough sleep.
- Some studies also suggest it might help reduce tiredness after a poor night of sleep, but this may not last if used continuously.
- Products combining glycine with other ingredients like magnesium and L-theanine may further help you fall asleep faster and sleep longer, but it is not clear how much glycine alone contributes.
Browse 4 studies
RCTNutritional Modulation of Sleep Latency, Duration, and Efficiency: A Randomized, Repeated-Measures, Double-Blind Deception Study2023n=9
In a crossover RCT of 16 adults, a nutritional blend with glycine, tryptophan, magnesium, and tart cherry improved self-reported sleep quality versus placebo.
- Effect
- Benefit
- Population
- Healthy adults
- Participants
- 9
- Avg age
- 24±3
The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers2012n=10
In a study of 10 partially sleep-restricted volunteers, glycine 3 g before bedtime reduced daytime sleepiness and improved psychomotor vigilance the next day.
- Effect
- Benefit
- Dose
- 3 g/day
- Population
- Healthy adults
- Participants
- 10
- Ages
- 30–61
Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes2007n=11
In volunteers with poor sleep quality, glycine 3 g before bedtime improved subjective sleep quality and reduced daytime fatigue.
- Effect
- Benefit
- Dose
- 3 g/day
- Population
- Healthy adults
- Participants
- 11
Subjective effects of glycine ingestion before bedtime on sleep quality2006n=15
In a study of 15 volunteers, taking glycine 3 g before bedtime for 4 days improved subjective sleep quality versus baseline.
- Effect
- Benefit
- Duration
- 4 days
- Dose
- 3 g/day
- Participants
- 15
ProbioticsView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Probiotics have insufficient evidence for Sleep.
Browse 1 study
RCTBifidobacterium adolescentis SBT2786 Improves Sleep Quality in Japanese Adults with Relatively High Levels of Stress: A Randomized, Double-Blind, Placebo-Controlled Study2024n=65
In 126 Japanese adults, Bifidobacterium adolescentis SBT2786 increased sleep duration and improved mood; stressed subgroup reported better sleepiness and daytime restfulness.
- Effect
- Benefit
- Population
- Adults
- Participants
- 65
- Ages
- 30–59
Vitamin B6View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Evidence is insufficient for this condition.
Browse 2 studies
RCTExploring the Effect of Lactium™ and Zizyphus Complex on Sleep Quality: A Double-Blind, Randomized Placebo-Controlled Trial2017n=171
A randomized trial of 171 healthy adults found that it currently cannot be concluded that administration of LZComplex3 for 2 weeks improves sleep quality, however, a marked placebo response (despite placebo run-in) and/or short duration of treatment may have masked a potential beneficial effect on sleep quality.
- Effect
- No Benefit
- Duration
- 2 weeks
- Population
- Healthy adults
- Participants
- 171
- Ages
- 18–65
Controlled trialEffects of pyridoxine on dreaming: a preliminary study2002n=12
A study of 12 subjects (18 to 28 yrs) found that vitamin B6 (250 mg or 100 mg/day before sleep for 5 days) enhanced dream salience, vividness, bizarreness, emotionality, and colour when compared to placebo. The higher vitamin B6 dose (250 mg/day) enhanced dream salience to a greater extent than 100 mg vitamin B6 or placebo for the first 3 days. Vitamin B6 may act by increasing cortical arousal during rapid eye movement (REM) sleep.
- Effect
- Benefit
- Duration
- 5 days
- Dose
- 100 mg/day
- Participants
- 12
ApigeninView supplement →
Do not purchase·★★★★★
How we scored this▸
- In people with primary insomnia lasting 6 months or more, taking 540 mg of chamomile extract daily (containing 24 mg apigenin) did not significantly improve sleep duration, quality, or how quickly they fell asleep compared to a placebo.
- There was a small, but not significant, improvement in daytime functioning.
- Chamomile may not be effective for treating primary insomnia.
Browse 1 study
RCTPreliminary examination of the efficacy and safety of a standardized chamomile extract for chronic primary insomnia: a randomized placebo-controlled pilot study2011n=34
A 28-day study including 34 participants (with primary insomnia for at least 6 months) found that 540 mg/day chamomile extract containing 24 mg apigenin, did not affect total sleep time, efficiency, latency or sleep quality compared to placebo. There was a modest, non-significant improvement in daytime functioning in the apigenin group compared to placebo.
- Effect
- No Benefit
- Duration
- 28 days
- Dose
- 540 mg/day
- Population
- Adults
- Participants
- 34
- Ages
- 18–65
QuercetinView supplement →
Do not purchase·★★★★★
How we scored this▸
- Quercetin has no meaningful benefit for Sleep.
Browse 1 study
RCTEffects of 6 weeks of quercetin supplementation on energy, fatigue, and sleep in ROTC cadets2011
In 58 ROTC cadets, quercetin 1 g/day for 6 weeks during military training did not affect energy, fatigue, or sleep quality versus placebo.
- Effect
- No Benefit
- Duration
- 42–54 days
- Dose
- 1 g/day
- Population
- Adults
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Valerian | ★★★★★72% | 7 | 1 | 22% |
| Ashwagandha | ★★★★★72% | 6 | 2 | 19% |
| Theanine | ★★★★★68% | 6 | 0 | 19% |
| Glycine | ★★★★★48% | 4 | 0 | 13% |
| GABA | ★★★★★48% | 3 | 0 | 9% |
| Vitamin B6 | ★★★★★44% | 2 | 0 | 6% |
| Apigenin | ★★★★★32% | 1 | 0 | 3% |
| Probiotics | ★★★★★44% | 1 | 0 | 3% |
| Quercetin | ★★★★★32% | 1 | 0 | 3% |
| Vitamin D | ★★★★★56% | 1 | 0 | 3% |