Evidence & research
Every claim in the library is tied to the literature. Here are all 82 research summaries in one place, each rated for evidence strength and linked to the underlying studies. Search by supplement or filter by how strong the evidence is.
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Showing 82 of 82 studies
Tongkat Ali and testosterone
Reviews of human trials report increases in testosterone, especially in men with low baseline levels.
Vitamin D and respiratory infections
Supplementation appears to modestly lower the risk of acute respiratory infections, with the largest benefit in deficient individuals.
Magnesium and sleep
Reviews suggest modest improvements in sleep parameters, especially in older adults or those with low intake.
Citicoline and attention
Randomized trials report improved attention and psychomotor speed in healthy adults and adolescents.
Ashwagandha and stress
Standardized extracts reduce perceived stress and cortisol versus placebo in several RCTs.
Collagen peptides and skin aging
A review of randomized trials found oral collagen improved skin hydration, elasticity, and wrinkle depth.
Ashwagandha and sleep
Trials report improvements in sleep quality and onset latency.
MTHFR variants and folate metabolism
The C677T and A1298C MTHFR polymorphisms reduce enzyme activity by 40–70%, impairing conversion of folic acid and raising homocysteine levels.
NAC and OCD / compulsive behaviours
Multiple RCTs show significant symptom reduction in OCD, trichotillomania, and other compulsive disorders with 1,200–2,400 mg/day.
B12 deficiency in vegans and older adults
B12 deficiency is prevalent in vegans without supplementation and in older adults with reduced gastric acid.
Vitamin D and bone fracture prevention
Pooled trials suggest vitamin D with calcium reduces fracture risk in older adults, particularly those who are deficient.
Omega-3 and triglycerides
Consistent dose-dependent reductions in triglycerides across many trials.
Omega-3 and depression
EPA-predominant formulations show modest benefit as an adjunct in depressive symptoms.
L-theanine and stress
Small studies suggest reduced stress and improved relaxation markers.
Calcium, vitamin D, and fractures
Combined calcium and vitamin D reduces fracture risk, especially in institutionalized older adults.
Homocysteine reduction with methylfolate
Active folate forms (methylfolate, folinic acid) are more effective than folic acid alone at lowering homocysteine in MTHFR carriers.
Glycine and collagen synthesis
Glycine supplementation increases collagen synthesis markers, supporting joint and skin health.
Arginine and erectile dysfunction
Supplemental arginine (3–6 g/day) improves erectile function scores in mild to moderate ED in multiple controlled trials.
Collagen for joint pain
Trials in athletes and osteoarthritis patients report reduced joint pain with daily collagen peptides.
Creatine and cognition
Early studies suggest cognitive benefits, particularly under stress such as sleep deprivation.
Caffeine as an ergogenic aid
Consistently enhances endurance and high-intensity exercise performance.
Probiotics and IBS
Some strains improve IBS symptoms, though benefits are strain- and individual-specific.
L-Methylfolate and depression
L-Methylfolate as an adjunct to antidepressants improves outcomes in patients with major depressive disorder, particularly those with MTHFR polymorphisms.
NAC and glutathione
Oral NAC reliably increases blood and tissue glutathione levels across a wide range of populations and conditions.
B12 and homocysteine reduction
B12 supplementation lowers homocysteine, especially when combined with folate and B6.
Glucosamine sulfate for knee osteoarthritis
Reviews find glucosamine sulfate offers small benefits for pain and function, with the sulfate form outperforming hydrochloride.
Psyllium and cholesterol
Meta-analyses confirm psyllium lowers LDL and total cholesterol in a dose-dependent way.
Rhodiola and stress
A standardized extract improved self-reported stress and related symptoms over several weeks in stressed adults.
Ginseng and fatigue
Reviews of randomized trials report reductions in mental and physical fatigue with Panax ginseng versus placebo.
Vitamin K2 and bone density
Some trials report improved bone mineral density and reduced fracture markers, though results vary by population and dose.
Zinc and the common cold
Lozenges started within 24 hours of symptoms may shorten cold duration, though dose and form matter.
Alternate-day iron dosing
Spacing doses may increase fractional absorption by reducing hepcidin spikes.
Creatine for strength and power
Decades of trials confirm improvements in strength, power, and lean mass with resistance training.
Citicoline and age-related cognition
Reviews suggest benefits for memory and cognition in older adults and in post-stroke recovery.
Probiotics and antibiotic-associated diarrhea
Specific strains reduce the risk of antibiotic-associated diarrhea in reviews.
NAC and COPD
High-dose NAC reduces exacerbations and improves lung function in chronic obstructive pulmonary disease.
Glutamine and gut permeability
Supplementation reduces markers of intestinal permeability in critically ill patients, surgical patients, and endurance athletes.
Citrulline malate and resistance exercise
8 g citrulline malate before training significantly increases repetitions to failure and reduces muscle soreness 24–48 h post-exercise.
Riboflavin for migraine prevention
High-dose riboflavin (400 mg/day) reduces migraine frequency in adults and children.
B6, homocysteine, and cardiovascular risk
B6 supplementation lowers homocysteine, especially when combined with folate and B12.
Inulin and gut bacteria
Trials show inulin-type fructans increase Bifidobacteria and support a healthier microbiome.
Rhodiola and fatigue
Standardized extracts reduced symptoms of stress-related and chronic fatigue versus placebo in multiple randomized trials.
Magnesium and metabolic health
Higher dietary magnesium is consistently associated with improved insulin sensitivity and lower type-2 diabetes risk.
Iron and fatigue in deficiency
Supplementation improves fatigue and work capacity in iron-deficient individuals, even without full anemia.
Caffeine and cognitive performance
Improves alertness, vigilance, and reaction time, especially when fatigued.
Curcumin and osteoarthritis
Trials suggest reduced joint pain and improved function, often comparable to NSAIDs with fewer GI effects.
Tryptophan and sleep
Supplemental tryptophan modestly shortens sleep latency and increases sleep efficiency in several small controlled trials.
Arginine and blood pressure
Meta-analysis of RCTs shows arginine supplementation significantly reduces systolic and diastolic blood pressure.
Vitamin K2 and arterial calcification
Preliminary trials suggest MK-7 may slow arterial stiffening, but larger outcome studies are needed.
Zinc and copper balance
Sustained high-dose zinc induces copper deficiency, supporting combined supplementation.
Copper-zinc balance
Maintaining copper intake offsets the copper depletion seen with sustained high-dose zinc.
Folate and neural tube defect prevention
Periconceptional folate supplementation reduces neural tube defect risk by 50–70% in clinical trials and population studies.
Tyrosine and stress-induced cognitive decline
Supplementation attenuates the decline in working memory and information processing seen under cold-stress and sleep deprivation.
Glutamine and immune function
Perioperative glutamine supplementation reduces infection rates and hospital stay duration in multiple clinical trials.
Citrulline vs arginine for blood arginine levels
Oral citrulline raises plasma arginine levels more effectively than equimolar arginine due to better intestinal absorption and reduced splanchnic extraction.
Boron and mineral metabolism
Boron supplementation reduces urinary calcium and magnesium loss and supports vitamin D status.
Boron and hormones
Short human trials report increases in free testosterone and changes in estrogen and inflammatory markers with daily boron.
Vitamin C and iron absorption
Co-ingestion markedly increases non-heme iron absorption in controlled studies.
Tryptophan, serotonin, and mood
Acute tryptophan depletion reliably worsens mood in vulnerable individuals, supporting the role of the serotonin pathway.
Niacin and lipid profile
High-dose niacin favourably alters HDL, triglycerides, and LDL in dyslipidaemia.
Pantethine and lipids
Pantethine supplementation shows modest reductions in LDL and triglycerides in some trials.
Psyllium for constipation and IBS
Soluble fiber from psyllium improves stool consistency and symptoms in constipation and IBS.
Vitamin C and the common cold
Regular supplementation modestly shortens cold duration but does not reliably prevent colds.
Huperzine A and cognition
Reviews of trials in Alzheimer's disease and cognitive decline report memory benefits, but caution that study quality is low.
Piperine as a bioavailability enhancer
Increases absorption of several nutrients and drugs by inhibiting their metabolism and transport.
Tyrosine and working memory
Improves working memory and cognitive flexibility in demanding but not routine cognitive tasks.
Betaine and athletic performance
Several RCTs report gains in power, strength, or body composition with ~2.5 g/day betaine, though findings are inconsistent across protocols.
Thiamine deficiency and neuropathy
Thiamine deficiency is a well-documented cause of peripheral neuropathy and Wernicke encephalopathy.
Tongkat Ali and stress hormones
A standardized extract reduced cortisol and improved mood scores in moderately stressed adults.
Glycine and sleep quality
3 g of glycine before bed improves subjective sleep quality and reduces daytime sleepiness and fatigue in controlled trials.
Uridine for mood
Small early studies, sometimes combined with omega-3s, suggest possible mood benefits but are limited in size and quality.
L-theanine, caffeine, and attention
The combination improves attention and reduces task-switching errors more than caffeine alone.
5-HTP and serotonin synthesis
5-HTP readily crosses the blood-brain barrier and is decarboxylated to serotonin, raising central serotonin more directly than tryptophan.
Ginseng and cognition
Trials suggest Panax ginseng can improve some aspects of cognitive performance and mood, especially under stress or fatigue.
Uridine, DHA, and synaptic membranes
Mechanistic and animal studies show uridine combined with DHA and choline increases synaptic membrane phospholipids and synaptic proteins.
Glucosamine and joint space narrowing
Long-term trials suggest glucosamine sulfate may slow joint space narrowing in the knee.
Inulin and mineral absorption
Prebiotic fibers can improve calcium absorption and bone mineral density in some studies.
Huperzine A mechanism
Pharmacology studies confirm it is a reversible inhibitor of acetylcholinesterase that crosses the blood-brain barrier.
Betaine and homocysteine
Betaine supplementation lowers plasma homocysteine in a dose-dependent manner via BHMT-mediated remethylation, independent of folate status.
5-HTP and mood
Small controlled trials suggest 5-HTP may improve low mood, but evidence quality and trial sizes are limited.
Curcumin bioavailability with piperine
Piperine substantially increases curcumin absorption in pharmacokinetic studies.
Biotin for brittle nails
2.5 mg/day biotin improved nail thickness and reduced splitting in people with brittle nails.
Reviewed by Vital Matrix Research Team. Research summaries are plain-language interpretations of the cited sources and are for educational purposes only, not medical advice. Many links point to PubMed searches so you can review the wider body of evidence yourself.