Research library / 198 articles
Evidence-aware explainers, practical supplement guides, and cognitive health research, written to show where confidence ends.
Human studies often associate lower folate or higher homocysteine with poorer cognition in older adults, but association does not establish causation. Randomized trials reliably lower homocysteine more often than they improve memory, executive function, or global cognition.
Human research suggests riboflavin may reduce migraine frequency in some adults, but the evidence base is small, heterogeneous, and not yet sufficient to establish how mitochondrial biology translates into reliable clinical benefit.
Human trials suggest that L-ornithine may influence subjective fatigue, mood, and some sleep-related measures in healthy adults, but the evidence remains small, short-term, and mostly from Japanese study populations. Cortisol findings are inconsistent, objective sleep evidence is limited, and clinical benefits for diagnosed conditions have not been established.
Human research suggests L-carnosine may influence selected glycation-related and metabolic biomarkers, but evidence remains limited, short-term, and concentrated in people with diabetes or metabolic risk. Healthy-aging findings often involve beta-alanine or anserine-carnosine mixtures rather than isolated L-carnosine.
Human research on alpha-ketoglutarate and aging remains early. A small uncontrolled formulation study and a larger observational cohort reported lower DNA-methylation-based biological-age measures, but neither establishes that AKG slows aging or improves healthspan. A randomized trial has been conducted, yet published results have so far focused on recruitment rather than efficacy.
Human research suggests resistant starch may modestly improve some glucose and insulin-resistance markers, but results vary by starch type and population. Direct evidence for improved cognition is sparse and does not yet establish a causal benefit.
Human studies suggest that inulin and related prebiotic fibres can influence some mood, memory, cognitive-flexibility, and food-decision outcomes, but the findings are mixed and population-specific. Microbiome changes often accompany these effects, yet no study has firmly established that microbiome changes cause the psychological outcomes.
Human trials suggest that some probiotic formulations may influence perceived stress, selected mood measures, and performance on certain cognitive tests. However, results vary by strain, population, outcome, and study design, so broad claims about probiotics as general mood or cognition enhancers are not established.
Human trials suggest that olive leaf extract may lower blood pressure modestly in some adults, particularly those with elevated blood pressure, but results are not consistent. The evidence is short-term, extract-specific, and not yet strong enough to establish a reliable general effect.
Controlled human studies suggest that aged garlic extract may modestly lower blood pressure in adults with elevated readings, while evidence for arterial function and cardiovascular risk markers remains preliminary, product-specific, and insufficient to establish effects on heart attacks, strokes, or mortality.
Human trials suggest grape seed extract may modestly influence blood pressure in some groups, but results are inconsistent and study populations are limited. Direct evidence for improved cognition is weaker: randomized trials in older adults with mild cognitive impairment and healthy young adults did not show a consistent cognitive benefit.
Human studies suggest that Pycnogenol can influence endothelial-dependent blood-flow measures and selected cognitive or oxidative-stress markers, but the evidence is based on small trials, surrogate outcomes, and several non-randomized registries. Benefits for cardiovascular events, disease progression, or broad cognitive enhancement remain unestablished.
Human trials suggest cocoa flavanols can produce short-term changes in regional cerebral perfusion or cortical oxygenation, especially in some healthy older adults. However, these vascular signals have not translated consistently into better cognitive performance, and large long-term trials in older adults have found no overall cognitive benefit.
Controlled human research suggests that a standardized oral lavender-oil preparation, Silexan, can reduce anxiety-rating scores over roughly six to ten weeks in adults with subthreshold anxiety or generalized anxiety disorder. The evidence is promising but product-specific, short-term, and not sufficient to establish effects for every lavender supplement or population.
Human studies suggest that some sage preparations can improve selected memory or attention-test scores, especially after acute use in healthy adults. Evidence in Alzheimer’s disease comes mainly from one small, short placebo-controlled trial. Formulations differ substantially, and long-term safety and real-world cognitive benefit remain uncertain.
Controlled human studies suggest that rosemary preparations can produce small, short-term changes in selected memory, attention, alertness, or processing-speed measures. However, the evidence is limited, heterogeneous, and insufficient to establish a reliable or lasting cognitive benefit.
Human research on gotu kola is limited and inconsistent. Small trials suggest possible short-term effects on working memory, alertness, or laboratory startle responses, but broader evidence does not establish reliable benefits for memory, attention, or anxiety symptoms.
Randomized trials suggest saffron extract may reduce depressive-symptom scores in some adults, but the evidence is based largely on short studies, small earlier samples, varied populations, and product-specific formulations. Newer trials show both modest benefit and no clear effect, so the findings support interest rather than firm conclusions.
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