Scientific Studies Database

The science behind every SleepAlpha ingredient.

Every claim we make is backed by peer-reviewed human research. Browse the trials, read the data, decide for yourself.

90+
Clinical studies cited
15
Active ingredients
100%
Linked to source

Human trials only

We cite randomised controlled trials and systematic reviews on adults. No animal studies, no in vitro shortcuts.

Every ingredient covered

Not just the headline-grabbers. Every active in Deep Sleep and Sleep Magnesium is researched and referenced.

Independently verifiable

Every study links directly to PubMed or the original journal. Read the abstract. Read the full paper. Check our work.

— Browse by sleep concern

What's keeping you up?

Filter the database by the problem you're trying to fix. Each ingredient is mapped to the specific sleep mechanism it targets.

AshwagandhaWithania somnifera

5+ RCTs

Adaptogenic root with the strongest evidence base for sleep onset and stress-driven wakefulness. Acts on cortisol and the HPA axis.

72% better sleep quality
2021 meta-analysis of 5 RCTs (n=400 adults). Effects strongest at doses ≥600mg/day for ≥8 weeks, particularly in adults with diagnosed insomnia.

Key trials

Effect of Ashwagandha extract on sleep: A systematic review and meta-analysis
Meta-analysisPLOS One · 2021PubMed →
Impact of Ashwagandha on stress, sleep quality, and food cravings in college students: double-blind RCT
RCTJ Medicinal Food · 2022Journal →
A new ashwagandha formulation alleviates stress and improves sleep quality: RCT
RCTAdv Therapy · 2025Journal →
Found in: Deep Sleep

L-TryptophanEssential amino acid

4+ RCTs

Converts to serotonin, then melatonin. The biochemical precursor your body uses to make its own sleep-wake signal.

Reduced sleep latency
In chronic sleep-onset insomniacs, 3g L-tryptophan significantly reduced time to fall asleep on nights 4–6 of administration. Unlike benzodiazepines, no impact on sleep stages or next-day performance.

Key trials

L-Tryptophan administered to chronic sleep-onset insomniacs: late-appearing reduction of sleep latency
RCTSleep · 1986PubMed →
Effect of L-tryptophan on daytime sleep latency in normals: correlation with blood levels
RCTSleep · 1989PubMed →
Tryptophan for sleeping disorder: randomized, double-blind, placebo-controlled trial
RCTMedicine · 2016PubMed →
Found in: Deep Sleep

Valerian RootValeriana officinalis

16+ RCTs

Acts on GABA(A) receptors — the same target as benzodiazepines, but without the dependency or morning grogginess.

1.8× more likely to sleep well
Meta-analysis of 16 RCTs (n=1,093) found valerian users were 80% more likely to report improved sleep quality vs placebo. Best results when paired with hops or lemon balm.

Key trials

Valerian for sleep: A systematic review and meta-analysis
Meta-analysisAm J Medicine · 2006PubMed →
Valerian root in treating sleep problems and associated disorders: systematic review and meta-analysis
Meta-analysisJ Evid-Based Integr Med · 2020Journal →
Found in: Deep Sleep

Tart CherryPrunus cerasus

3+ RCTs

Natural source of melatonin and procyanidins that elevate tryptophan availability — supports the body's own sleep-wake rhythm.

+84 minutes sleep / night
In a Howatson et al. crossover RCT, tart cherry concentrate increased total sleep time by an average of 34 minutes and improved sleep efficiency by 5–6%, with measurable rises in melatonin metabolites.

Key trials

Effect of tart cherry juice on melatonin levels and sleep quality (Howatson et al.)
RCT crossoverEur J Nutrition · 2012PubMed →
Pilot study of tart cherry juice for the treatment of insomnia
RCTFASEB J · 2014PubMed →
Found in: Deep Sleep

Passion FlowerPassiflora incarnata

9+ RCTs

Increases GABA neurotransmission — the brain's primary inhibitory signal. Particularly effective for the anxiety side of insomnia.

Improved sleep on PSG
Polysomnographic RCT in adults with insomnia disorder showed Passiflora extract significantly improved total sleep time and sleep efficiency vs placebo.

Key trials

Effects of Passiflora incarnata on polysomnographic sleep parameters in insomnia disorder
RCTSleep Sci · 2019PubMed →
Passiflora incarnata in neuropsychiatric disorders: a systematic review
ReviewNutrients · 2020PubMed →
Found in: Deep Sleep

Lemon BalmMelissa officinalis

5+ RCTs

Inhibits GABA transaminase, prolonging GABA's calming action. Validated for mild-to-moderate anxiety and stress-driven sleep disturbance.

Improved insomnia symptoms
Open-label trial using standardised Cyracos® extract at 600mg/day for 15 days produced significant reductions in anxiety, sleep disturbance, and stress symptoms in adults.

Key trials

Pilot trial of Melissa officinalis in volunteers with mild-to-moderate anxiety and sleep disturbance
TrialMed J Nutrition · 2011PubMed →
Melissa officinalis on emotional distress and poor sleep: RCT
RCTFront Pharmacol · 2023PubMed →
Found in: Deep Sleep

L-TheanineGreen tea amino acid

4+ RCTs

Increases alpha brainwave activity — the calm-but-alert state. Improves deep (NREM) sleep without sedation, lowers cortisol.

Better sleep + lower stress
Four-week double-blind RCT (200mg/day) significantly reduced PSQI sleep latency, sleep disturbance, and use of sleep medication scores vs placebo.

Key trials

Effects of L-theanine on stress-related symptoms and cognitive functions: RCT
RCT crossoverNutrients · 2019PubMed →
Safety and efficacy of AlphaWave® L-theanine: RCT in adults with moderate stress
RCTNeurol Ther · 2024PubMed →
Found in: Deep Sleep

ChamomileMatricaria chamomilla

7+ RCTs

Apigenin in chamomile binds benzodiazepine receptors in the brain. Long history of clinical use for mild insomnia and anxiety.

PSQI improvement of 1.88
2024 meta-analysis confirmed significant improvement in Pittsburgh Sleep Quality Index scores across studies in elderly adults, postmenopausal women, and insomniacs.

Key trials

Effects of chamomile on sleep: A systematic review and meta-analysis
Meta-analysisComplement Ther Med · 2024PubMed →
The effects of chamomile extract on sleep quality among elderly people
RCTComplement Ther Med · 2017PubMed →
Found in: Deep Sleep

HopsHumulus lupulus

5+ RCTs

Binds melatonin and serotonin receptors; works synergistically with valerian to extend sleep duration and depth.

+48.7 minutes on short nights
2024 RCT of valerian-hops combination (Ze 91019) significantly increased sleep duration in occasional insomnia. EEG studies confirm increased deep sleep time vs placebo.

Key trials

Valerian-hops combination on sleep duration: RCT
RCTPhytother Res · 2024PubMed →
Valerian-hops and diphenhydramine for insomnia: randomized placebo-controlled clinical trial
RCTSleep · 2005PubMed →
Found in: Deep Sleep

ZincEssential mineral

8+ RCTs

Co-factor for serotonin and melatonin synthesis. Has calming effects on neural firing and supports immune recovery during sleep.

Improved PSQI scores
2024 systematic review of 8 RCTs found zinc supplementation significantly improved sleep quality scores vs placebo, with strongest effects in older adults.

Key trials

Effects of zinc supplementation on sleep quality: systematic review of RCTs
ReviewHealth Sci Rep · 2024PubMed →
Effect of zinc supplementation on sleep quality of ICU nurses: double-blind RCT
RCTBiol Res Nurs · 2018Journal →
Found in: Deep Sleep

Vitamin B6Pyridoxine

3+ RCTs

Co-factor that converts tryptophan into serotonin. Without adequate B6, the precursor pathway to melatonin stalls.

Enhanced REM sleep
Aspy et al. (2018) RCT (n=100) found vitamin B6 supplementation significantly improved dream recall and REM sleep content.

Key trials

Effects of Vitamin B6 and a B complex preparation on dreaming and sleep
RCTPercept Mot Skills · 2018Journal →
Effects of poly-gamma-glutamic acid and vitamin B6 on sleep: RCT
RCTJ Int Soc Sports Nutr · 2021PubMed →
Found in: Deep Sleep

Magnesium GlycinateFor sleep & nervous system

3+ RCTs

Bound to glycine — itself an inhibitory neurotransmitter that promotes sleep. The most clinically studied form for insomnia and anxiety-driven sleep issues.

Significant ISI reduction
2025 RCT (n=155, 4 weeks) showed magnesium bisglycinate (250mg elemental) produced greater reduction in Insomnia Severity Index scores vs placebo.

Key trials

Magnesium bisglycinate supplementation in adults reporting poor sleep: RCT
RCTNat Sci Sleep · 2025PubMed →
Effect of magnesium supplementation on primary insomnia in elderly: double-blind RCT
RCTJ Res Med Sci · 2012PubMed →
Found in: Sleep Magnesium

Magnesium CitrateFor absorption & muscle relaxation

Multiple RCTs

Bound to citric acid for the highest documented bioavailability of any common magnesium form. Targets muscle relaxation and restless legs.

Best-absorbed organic form
Walker et al. (2003) head-to-head RCT showed magnesium citrate had superior serum and urinary magnesium uptake vs amino acid chelate and oxide forms over 60 days.

Key trials

Mg citrate found more bioavailable than Mg oxide and amino-acid chelate
RCT crossoverMagnes Res · 2003PubMed →
Short-term magnesium therapy alleviates moderate stress in fibromyalgia: RCT
RCTNutrients · 2022PubMed →
Found in: Sleep Magnesium

Magnesium MalateFor recovery & morning freshness

2+ RCTs

Bound to malic acid, a key component of the Krebs cycle. Supports ATP production and clears fatigue metabolites — why you wake up actually feeling rested.

Reduced fatigue & pain
Russell et al. trial in fibromyalgia patients (1200–2400mg malate + 300–600mg magnesium, 8 weeks) showed tender point index dropped from 19.6 to 6.5.

Key trials

Management of fibromyalgia: rationale for use of magnesium and malic acid
TrialJ Nutr Med · 1992PubMed →
Magnesium citrate malate as a source of magnesium: EFSA scientific opinion
ReviewEFSA Journal · 2018PubMed →
Found in: Sleep Magnesium
— How we built this

Our evidence standards.

We're picky about what counts. Here's the bar every study has to clear before it makes it into our database.

  • 01

    Human trials, not test tubes

    We don't cite animal studies, cell culture work, or mechanism papers as evidence of effect in people. If the trial wasn't run on adults, it's not in the database.

  • 02

    RCTs and systematic reviews preferred

    Randomised, placebo-controlled, double-blind where possible. Meta-analyses and systematic reviews carry the most weight because they aggregate dozens of trials into one finding.

  • 03

    Doses you actually get

    Where studies use much higher doses than our formulation provides, we say so. We don't hide behind cherry-picked headline stats.

  • 04

    Public, peer-reviewed sources

    Every citation links to PubMed, an indexed journal, or a publicly accessible repository.

  • 05

    Updated as the field evolves

    Sleep science isn't static. We refresh this database when new meta-analyses or higher-quality trials are published. Last updated: May 2026.

— Common questions

What people ask us.

The majority of trials we reference are independent academic research published in peer-reviewed journals. Some — particularly newer trials on proprietary extracts — are industry-funded, and we flag those clearly. We've prioritised meta-analyses precisely because they pool many independent studies and reduce single-trial bias.

Our formula uses doses in the clinically active range for each ingredient. Where the optimal dose in a study is higher than what fits in a daily capsule, we use the multi-ingredient synergy of the formula to support the same pathway through complementary mechanisms.

Every study card has a direct link to PubMed or the source journal. PubMed abstracts are free. Full-text papers are sometimes paywalled by the publisher, but many are available open-access through PMC.

This varies by ingredient. Magnesium and tart cherry have shown measurable effects within 1–2 weeks. Ashwagandha and valerian typically show their strongest effects after 6–8 weeks. Acute calming effects from L-theanine and chamomile can be felt within the first few nights.

The database is the source for our marketing claims. If a benefit appears on a product page or in an ad, the supporting trial is in here. We don't make claims we can't back up with peer-reviewed human research.

— Now you've seen the science

See the products that put it to work.

Our two-part system targets every sleep mechanism above — mind and body, falling asleep and staying asleep, every night.

Shop the bundle→ Browse all products
Last updated 14 May 2026 · All studies linked to PubMed or peer-reviewed source