THE LEDGER
The research behind Nightspan.
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18 research records covering 5 included ingredients and historical exclusions for Nightspan. The ledger includes trials, reviews and other source types; several records can concern the same ingredient. Every row links its source. Explore the ingredient evidence and see how the choices fit the Nightspan formula.
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| Ingredient | Source | Design | Funding, as disclosed | Verdict |
|---|---|---|---|---|
| Glycine | Yamadera et al. 2007 (Sleep and Biological Rhythms)3 g before bed shortened time to fall asleep and time to reach slow-wave sleep in volunteers with unsatisfactory sleep. Sleep architecture was unchanged; reaching deep sleep sooner does not mean more deep sleep. This was not a trial of Nightspan. | Human sleep study with polysomnography and self-reported outcomes | Authors affiliated with Ajinomoto, an amino-acid manufacturer | included |
| Glycine | Inagawa et al. 2006 (Sleep and Biological Rhythms)3 g before bed was studied in volunteers dissatisfied with their sleep. Morning questionnaires reported improvements in fatigue and related subjective measures. This is a separate study from the 2007 sleep-lab paper; it does not establish a change in sleep stages or a finished-formula benefit. | Randomized, double-blind crossover; next-morning questionnaires | Authors affiliated with Ajinomoto, an amino-acid manufacturer | included |
| Glycine | Bannai et al. 2012 · next-day fatigue and vigilanceReported fatigue improved on day one, but not day three. Reaction times on a sustained-attention test improved on both measured days; the other performance tests did not show significant differences. Participants and several authors were affiliated with Ajinomoto. This very small, short study tested glycine alone. It does not show that Nightspan treats ongoing fatigue or replaces sufficient sleep. | Randomized, single-blind crossover; seven healthy men analyzed; 3 g glycine or placebo before bed during three nights with time in bed reduced by 25%. | Participants and several authors affiliated with Ajinomoto | included |
| Magnesium bisglycinate | Schuster et al. 2025 (Nature and Science of Sleep), N=155The daily intervention supplied 250 mg elemental magnesium and 1,523 mg glycine. Insomnia-severity scores improved modestly versus placebo; secondary questionnaire outcomes did not differ significantly. It does not isolate magnesium's contribution or show an added benefit in Nightspan's combination. | Four-week randomized, placebo-controlled trial; questionnaires | Leibniz University Hannover institute; an author disclosed a research-business relationship with nutraceutical companies | included |
| L-theanine | Bulman et al. 2025 (Sleep Medicine Reviews), 19 articles, N=897Some self-reported sleep outcomes improved; pooled objective sleep measures did not show a significant improvement. Several interventions combined theanine with other ingredients. The review does not establish an optimal dose, duration, or finished-formula effect. | Systematic review; 18 articles included in meta-analysis | Three authors disclosed a University of Canberra grant; other authors declared no conflicts | included |
| GABA | Yamatsu et al. 2016 (Food Science and Biotechnology), N=10100 mg shortened EEG-measured sleep latency in a one-week crossover of 10 poor sleepers; most other outcomes did not reach significance. Historical research only: GABA is not included in the current five-active Nightspan formula. | Human EEG, single-blind crossover | Authored by employees of the ingredient manufacturer | left out by design |
| Saffron extract | Lopresti et al. 2021 (Sleep Medicine), N=12028 mg one hour before bed improved sleep-diary ratings vs placebo over 28 days; no sleep-lab measurement. The 2020 trial (N=63) dosed 14 mg twice daily. | Randomized controlled trial, sleep-diary endpoints | Funded by the extract's manufacturer | included |
| Zinc | Saito et al. 2017 (Molecular Nutrition & Food Research), N=120The trial supplied zinc in a food, not as the Dayspan formula. It does not establish a sleep benefit for zinc bisglycinate. Zinc's current formulation rationale is nutritional adequacy; that is separate from this historical sleep research. | Human trial with actigraphy | Industry-authored | included |
| Apigenin | Primary GABA-A electrophysiology (four independent labs)No human sleep trial of isolated apigenin exists at any dose; ~99% water-insoluble; the bench work shows inhibition, not enhancement. | Bench electrophysiology | — | rejected |
| Ashwagandha | NIH LiverTox monographBest sleep-trial evidence of anything we rejected — cut on safety: graded a likely cause of clinically apparent liver injury; banned in Danish food supplements. | Safety database | — | rejected |
| Melatonin | Sleep-architecture research (slow-wave suppression, spindle increase)A timing signal, not a sedative; pooled sleep-onset effect ≈7 minutes. It does change sleep architecture, contrary to the industry line. | Human sleep research | — | left out by design |
| Valerian | Valerenic-acid mechanism and human pharmacokineticsReal mechanism, unreachable dose: human blood levels miss the functional requirement by roughly a thousandfold. | Mechanism + human PK | — | rejected |
| Alpha-ketoglutarate | Ongoing placebo-controlled trial (NCT05706389)No human or animal sleep evidence at all; its actual literature is lifespan and 'biological age' work. | Ongoing randomized trial — no sleep endpoint | — | rejected |
| Resveratrol / polydatin | Four human trials with sleep as a secondary endpointAll four null. The one title suggesting otherwise was an NAC + lactoferrin + 59 mg resveratrol combination in interferon-treated hepatitis C patients. Also inhibits warfarin clearance. | Human trials, secondary endpoints | — | rejected |
| Palmitoylethanolamide (PEA) | Pre-registered randomized sleep trial with actigraphyA fair test, failed: all three pre-registered primary endpoints missed. The easiest possible exclusion. | Randomized controlled trial, objective measurement | — | rejected |
| Ellagic acid / urolithin A | Two sleep trials in diagnosed patientsOne reports a baseline sleep efficiency of 8.8% — physiologically impossible, and quoted unchallenged in a peer-reviewed review. Urolithin A has no sleep endpoint in any trial. | Trials in diagnosed patient populations | — | rejected |
| Myo-inositol | Single randomized trial, 2 g nightly, third-trimester pregnancyA real subjective result, never replicated in ordinary poor sleepers. Citing it to you would be borrowed evidence. | Randomized trial in one specific population | — | rejected |
| Oxaloacetate | 2024 RESTORE ME randomized trial (ME/CFS, fatigue endpoint)Sleep appears nowhere as an outcome. Fatigue and sleepiness feel adjacent, which is exactly why the distinction matters. | Randomized fatigue trial in a disease population | — | rejected |
Study results and limitations belong together. These verdicts concern ingredient choices for Nightspan, not every possible use of an ingredient or a trial of the finished powder. Inclusion is a formulation decision, not a finding that the ingredient or the combination delivers a sleep benefit.
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