L-Theanine
An amino acid found in tea leaves. It is studied for promoting a calm, settled kind of attention without sedation, which fits a stimulant-free focus direction.
Read the full breakdownIngredient library
Every ingredient, held to the same standard.
Each page follows the full The Signal template: what it is, who it's for, how strong the evidence is, studied doses and forms, cautions, interactions, and label guidance.
Educational content, not medical advice. Evidence grades are our own conservative reading of the human research — they are not product claims.
Want to filter by grade, goal, or in-formula status — or compare ingredients side by side? Try the Evidence Explorer.
Signal State Core
The researched candidate set for v1.
The stimulant-free cognitive actives and foundational nutrients we're researching as candidates for Signal State Core — held to the same standard as everything else in the library. A working direction, not a final formula: the shortlist, doses, and claims are all subject to manufacturing and regulatory review.
Citicoline
A choline-donating compound the body uses in cell-membrane and neurotransmitter pathways. It is studied as a focus and mental-energy ingredient.
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Bacopa Monnieri
A traditional herb standardized for compounds called bacosides. It is studied mainly for memory and learning over sustained daily use, not for same-day effects.
Read the full breakdownRhodiola Rosea
An adaptogenic herb standardized for rosavins and salidroside. Its studied benefit is narrow: reducing stress-related mental fatigue and helping sustain output during genuinely demanding stretches (night shifts, exam load) — not lifting baseline performance in a rested, unstressed adult.
Read the full breakdownB-Complex (B6, B9, B12)
The nervous-system B vitamins — B6, folate, and B12 — support normal neurological and psychological function and normal nutrient metabolism. Measurable cognitive benefit is strongest where baseline status is low or homocysteine is elevated (typically older adults); it is limited in young, well-nourished people.
Read the full breakdownVitamin D3
A foundational fat-soluble nutrient, not a same-day nootropic. There is no reliable evidence it sharpens focus in people who already have adequate levels, but low vitamin D status is common at Canadian latitudes in winter and is associated with poorer cognition — so it fits as foundational "status insurance," not a cognitive active.
Read the full breakdownAlso in the library
Researched, not on the v1 shortlist.
Ingredients we've researched to the same standard for education, comparison, and future formulas — not currently candidates for Signal State Core v1.
Cocoa Flavanols
A de-theobrominated cocoa extract studied for acute cerebral blood flow and attention. A large chronic trial on global cognition was honestly null, so the qualified acute claim is what the grade rests on.
Read the full breakdownHoly Basil
An adaptogenic herb studied across multiple independent manufacturers for supporting a healthy stress response and cortisol balance — the multi-sponsor replication is what earns it a B rather than a C.
Read the full breakdownIron
An essential mineral whose cognition, energy, and mood benefit is real but conditional: it applies specifically to iron-deficient individuals, most often menstruating women, not to iron-replete adults, who should not blanket-dose it.
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L-Tyrosine
An amino acid the body uses to make dopamine and norepinephrine. It is studied for protecting focus and working memory when the brain is taxed by stress, sleep loss, or cold — not as an everyday enhancer for well-rested people.
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Lavender (oral)
An oral lavender-oil softgel studied in double-blind trials for easing occasional nervous tension and supporting calm, with no sedation or dependence signal in its trials. Not the same as aromatherapy lavender.
Read the full breakdownLemon Balm
An herb studied in replicated, independent trials for supporting acute calm under cognitive load — a narrower and better-evidenced claim than a general anti-anxiety one.
Read the full breakdownMelatonin
The body's own sleep-timing hormone, taken as a low-dose evening supplement. Its best evidence is for shortening how long it takes to fall asleep and for re-aligning a shifted body clock (jet lag, shift work, delayed sleep phase) — not as a general sedative or a cure for chronic insomnia. An evening, sleep-slot ingredient, not a daytime cognitive active.
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Vitamin C
An essential vitamin that supports attention and processing specifically by correcting inadequate status — a common but often-overlooked gap, not a stimulant or a cognitive enhancer above and beyond replete levels.
Read the full breakdown5-HTP
The immediate serotonin precursor, extracted from Griffonia simplicifolia seed, that crosses into the brain more readily than tryptophan. Small trials suggest benefit for mood and sleep, but quality is low and it carries the same serious serotonin-syndrome interaction with antidepressants. An evening/mood-slot ingredient requiring conservative dosing.
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Acetyl-L-Carnitine
An acetylated form of the amino acid carnitine, studied for cellular energy and age-related cognitive support. Its benefit in healthy, high-functioning adults is largely unproven, so it is positioned honestly as a mitochondrial-energy ingredient rather than a same-day focus booster.
Read the full breakdownAlpha-GPC
A highly bioavailable choline source studied mainly in older or impaired populations, not healthy high-performers. Healthy-adult cognition data is limited, and a very large 2021 observational study flagged an association with higher stroke risk — an association, not a proven cause, but enough that citicoline is the more defensible choline pick for a healthy-adult stimulant-free product.
Read the full breakdownAmerican Ginseng
A caffeine-free adaptogen, botanically distinct from Asian Panax ginseng, studied for acute working-memory support. The signal is real for a single dose; chronic daily use has not held up as well.
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Anthocyanins
Colorful plant polyphenols found in berries. They are studied for antioxidant activity and circulation, with interest in longer-term cognitive-health positioning.
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Ashwagandha
A calming adaptogen with solid human evidence for reducing stress, anxiety, and cortisol at 300–600 mg/day of standardized extract. Any cognitive benefit is mostly downstream of stress relief and is still emerging in healthy adults.
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Chamomile
A gentle, well-tolerated evening botanical studied for mild anxiety and sleep quality, plausibly via the flavone apigenin acting on GABA pathways. The effect is genuine but small, and the sleep data are early — a calm-slot ingredient, not a sedative.
Read the full breakdownCreatine Monohydrate
Best known for muscle, creatine is also a brain energy-buffer. The cognition evidence is emerging and modest, and it is clearest exactly when the brain is energy-stressed — sleep deprivation and low dietary baseline (vegetarians) — rather than in rested, omnivorous, healthy adults. Extremely cheap with a strong safety record.
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Curcumin (lipidated)
A bioavailability-enhanced curcumin extract studied in healthy older adults for modest working-memory and mood support. The trial base is real but narrow — same-group replication and an older-adult skew.
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Ginkgo Biloba
A well-characterized stimulant-free botanical with a dedicated Health Canada monograph that allows a cognition/memory claim. Its best human evidence is in older adults with cognitive symptoms; in healthy adults the benefit is small and inconsistent.
Read the full breakdownHuperzine-A
A plant-derived compound that strongly and selectively blocks the enzyme that breaks down acetylcholine — the same mechanism as some prescription memory drugs. That drug-like potency, thin healthy-adult evidence, and cholinergic side-effect profile make it a serious ingredient to handle carefully, not a casual add.
Read the full breakdownL-Tryptophan
The dietary amino-acid precursor to serotonin and melatonin, studied mainly for sleep onset and mood. Small trials show modest, inconsistent benefits for falling asleep. It carries a serious serotonin-syndrome interaction with antidepressants and a manufacturing-safety history worth understanding — an evening/mood-slot ingredient, not a daytime active.
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Lutein + Zeaxanthin
A pair of dietary carotenoids that accumulate in neural tissue, not just the eye, and are studied for supporting processing speed and sustained attention. Well-tolerated and well-studied for eye health; the cognitive-processing-speed angle is real but younger and narrower.
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Magnesium Glycinate
A well-absorbed, low-laxative form of an essential mineral, used as an evening calm/sleep foundation. Its human evidence for sleep and stress is real but modest and concentrated in people who are low to begin with — a mild, mainly-if-you're-deficient effect, not a sedative. This is the everyday repletion form; the CNS-targeted cognition pitch belongs to magnesium L-threonate, a different form graded Emerging.
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Maritime Pine Bark
A polyphenol-rich extract studied for circulation and antioxidant activity, with some interest in attention endpoints. Evidence quality varies by extract.
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Omega-3 (EPA/DHA)
A foundational dietary fat (EPA and DHA) that most people under-consume; DHA is a major structural lipid in the brain. It earns its place as a baseline-nutrition layer, not a same-day focus ingredient — controlled trials in already-healthy adults have generally not shown a cognitive-enhancement effect.
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Panax Ginseng
A well-tolerated adaptogen whose cognition evidence is genuinely weak on independent review, though single-dose trials show a milder mental-fatigue signal. This is claim-specific grading: Asian Panax ginseng for cognition grades C; a stronger fatigue signal exists but belongs to American ginseng, a different species, not this one.
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Passionflower
A traditional calming botanical studied in small trials for anxiety and subjective sleep, with a consistent direction of benefit but no large confirmatory trial. A gentle evening/as-needed calm-slot option rather than a proven sleep aid.
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Phosphatidylserine
A phospholipid that is part of cell membranes, including in the brain. Its most persuasive memory trials used a bovine-cortex source in memory-impaired older adults; modern soy- and sunflower-derived PS — what every current supplement actually contains — has not cleared that same bar.
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Resveratrol
A grape-skin polyphenol studied for supporting cerebral blood flow and verbal memory. The strongest human trial base is concentrated in postmenopausal women from a single research group.
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Saffron
A well-tolerated botanical with strong human evidence for mood and stress and secondary sleep benefits, standardized as branded extracts. Its role in a cognitive stack is as a mood- and stress-resilience component, not a proven direct cognition enhancer.
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Sage
Standardized sage extracts show a modest, mostly same-day boost to memory and attention in healthy adults, plausibly by slowing the breakdown of acetylcholine. The evidence is early-stage and dominated by small or industry-funded trials.
Read the full breakdownSpearmint Extract
A phenolic-rich spearmint extract studied for supporting working memory and attention, with its pivotal trial run in adults with age-associated memory concerns rather than a broad healthy-adult population.
Read the full breakdownValerian
A traditional evening sedative herb. Despite centuries of use, the best systematic reviews find its efficacy for sleep genuinely unproven: a weak subjective "slept better" signal that objective sleep measures do not confirm, built on low-quality, non-standardized trials. Included for transparency and traditional-use context, not on a strong efficacy claim.
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Vitamin K2 (MK-7)
A fat-soluble vitamin that activates the proteins directing calcium into bone rather than soft tissue. It is a foundational cofactor for vitamin D, not a cognitive ingredient, and it carries one significant caution: it directly interacts with warfarin and other vitamin K antagonists.
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Zinc
An essential mineral for immune function, taste, and brain signaling. Its cognition and mood benefit is real but largely confined to correcting a deficiency or augmenting antidepressants — for a well-nourished adult it is best understood as deficiency insurance, not a focus or mood enhancer, and chronic high doses carry a real copper-depletion downside.
Read the full breakdownZynamite
A caffeine-free mango-leaf extract studied for acute alertness and attention through COMT inhibition, without the blood-pressure or heart-rate activation a stimulant would carry. Human data is acute and single-dose so far.
Read the full breakdownGlycine
A simple amino acid taken before sleep, studied for supporting sleep quality and next-day alertness. It belongs in an evening slot, not a daytime stack, and the trial base is concentrated with one manufacturer.
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Lion's Mane
An edible mushroom studied for long-term cognitive support. Human evidence is still limited, so it is positioned as an emerging ingredient with sourcing and extract-quality considerations.
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Magnesium L-Threonate
A magnesium salt marketed specifically for the brain because it raised brain magnesium in rodents. The cognition story is mostly preclinical plus a couple of small, largely developer-linked human trials — it is the most over-marketed relative to its human evidence in this library. Magnesium as a general mineral has separate, better-established roles.
Read the full breakdownPQQ
A mitochondrial-biogenesis cofactor studied for cognition and fatigue. The positive human trials all come from one branded-ingredient sponsor, with no independent replication yet.
Read the full breakdownSceletium Tortuosum
A South African succulent extract studied in small trials for mood and cognitive flexibility. The trial base is small and sponsor-linked, and it carries a specific interaction caution with serotonergic and MAOI medications.
Read the full breakdownUridine
A nucleotide that supplies a synaptic-membrane building block, mechanistically paired with choline sources and DHA. Human cognition evidence in healthy adults doesn't exist yet — what exists is biomarker data and a prodromal-Alzheimer's stack trial, not this population.
Read the full breakdownApoaequorin
A jellyfish-derived calcium-binding protein marketed for memory, best known as the active ingredient in Prevagen. It failed its own sponsor-run trial on primary endpoints, was the subject of an FTC deceptive-advertising action, and is mechanistically implausible as an oral supplement.
Read the full breakdownDMAE
A small choline-related molecule marketed on the theory that it raises acetylcholine. That mechanism is poorly confirmed, healthy-adult cognition evidence is weak and dated, and animal studies show developmental-toxicity signals — so for a conservative, review-ready brand it is best understood as a flagged ingredient rather than a candidate.
Read the full breakdownSelenium
An essential mineral for antioxidant selenoproteins and thyroid function. Low status is linked to cognitive decline in observational data, but that reflects deficiency correction, not a nootropic effect — and North American diets are generally selenium-sufficient. Graded out as a featured cognitive active on a safety veto: it has one of the narrowest therapeutic windows of any micronutrient, and supplementation RCTs are null for cognition.
Read the full breakdownVinpocetine
A semi-synthetic compound derived from a periwinkle-plant alkaloid, marketed as a nootropic. The FDA has stated it does not meet the legal definition of a dietary ingredient, and issued a 2019 safety alert over reproductive-harm risk.
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Vitamin E
An essential lipid-membrane antioxidant that is legitimate for correcting a (rare) deficiency, but graded out as a featured cognitive active on a safety signal: the supplemental doses studied for brain and heart benefit are associated with increased all-cause mortality and, in men, increased prostate cancer risk, while healthy-adult cognitive prevention is null.
Read the full breakdownHow we grade evidence
Four grades, conservatively applied.
Grades reflect our own reading of the human research for an ingredient's studied role — not product claims, and not a promise of effect.
Grade A
Strong — multiple human trials and consistent effects
Grade B
Moderate — several human trials, some mixed results
Grade C
Limited — early or small human trials
Emerging
Emerging — mostly preclinical or preliminary human data
This is the short version. For the full rubric — study type, replication, population match, dose adequacy, and conflict-of-interest checks — see The Evidence Standard.