Brain

Nutrients connected to Brain

A link means the body needs the nutrient for this, or that low intake is linked to it. It does not mean extra supplements help if your intake is already adequate; each link shows how strong the evidence is.

• Vitamin B1 (thiamin)Established role

  The brain depends on thiamin for energy; severe deficiency can cause Wernicke disease and Korsakoff syndrome.

• ManganeseDocumented risk

  Overexposure to manganese is linked to disturbance of the brain's dopamine system. This is a safety signal, not a benefit.

• TyrosineEstablished role

  Brain cells use tyrosine as the starting material for dopamine and norepinephrine. Normal intake already covers this role.

• Omega-3 fatty acids (ALA, EPA and DHA)Established role

  DHA is a major building block of the brain and retina. This is its normal role; it does not show that extra supplements improve brain function.

• Caffeine supplementsClinically supported

  Caffeine acts on the brain to increase alertness; short-term attention tasks improve in rested healthy adults.

• GABA supplementsEstablished role

  GABA is the main calming messenger in the brain. Whether oral GABA reaches the brain is unresolved.

• NeemDocumented risk

  Swallowing neem oil has caused seizures, coma and brain damage in case reports; this is a documented harm, not a benefit.

• TansyDocumented risk

  Convulsions and loss of consciousness are listed with tansy oil poisoning.

• KratomDocumented risk

  The main compounds activate opioid receptors in the brain; effects range from alertness to sedation and confusion, with dependence risk.

• Thuja (northern white cedar)Documented risk

  Thujone in thuja can cause convulsions; the EU herbal committee calls it a neurotoxicant. This is a safety concern, not a benefit.

• EpazoteDocumented risk

  A toddler who received epazote oil had brain swelling at autopsy and died; Moroccan reports describe toxic encephalopathy in an infant.

• KhatDocumented risk

  Khat stimulants act on the brain; the DEA reports dependence and psychosis with chronic use.

• Star Fruit (Carambola)Documented risk

  Confusion, coma and seizures including status epilepticus have been reported after star fruit in people with kidney failure.

• Belladonna (deadly nightshade)Documented risk

  Central effects include confusion, incoherent speech and hallucinations; one case needed ICU sedation.

• Angel wingDocumented risk

  Poisoning caused acute encephalopathy with deep brain lesions and loss of nerve insulation (myelin) in people with kidney failure.

• Ginkgo NutsDocumented risk

  The toxin is thought to lower GABA and raise glutamate in the brain, leading to convulsions.

• Nutmeg OilDocumented risk

  Altered consciousness and delirium are reported after large nutmeg intakes (spice, not oil).

• Camphor Oil (Dangers)Documented risk

  Seizures after swallowing or heavy skin use.

• Hyssop OilDocumented risk

  Seizures linked to hyssop oil in reviews and case reports.

• Sage Oil (Dalmatian and Spanish)Documented risk

  Seizures are reported after sage oil intake in the EU assessment.

• Vitamin B12Deficiency link

  Memory problems, confusion and dementia from metabolic causes are listed with B12 deficiency.

• IodineDeficiency link

  Deficiency in pregnancy and infancy can impair brain development. This concerns deficiency, not adults with enough iodine.

• CopperDocumented risk

  Copper is linked to brain development, and in Wilson disease extra copper can damage the brain. The brain-development role is described only as 'thought' to matter by the NHS.

• BCAAs (leucine, isoleucine, valine)Documented risk

  In maple syrup urine disease, build-up of these three amino acids is toxic to the brain.

• TaurineLab or animal research only

  Taurine is among the most abundant amino acids in the brain. Its exact actions are not fully known, and this does not prove supplements benefit the brain.

• Caffeine plus L-theanine and brain formulasClinically supported

  Caffeine acts on the brain to promote alertness; blend benefits are unproven.

• Citicoline and alpha-GPCPreliminary or mixed

  The brain is where the compounds are meant to act. Results are mixed and mostly from patients.

• Bacopa monnieriPreliminary or mixed

  Trials test memory and attention; effects on brain structure or disease were not shown in the sources we read.

• Ginkgo bilobaPreliminary or mixed

  Studies examine ginkgo extract for thinking and dementia; results are mixed and do not show prevention.

• Botanical and mushroom nootropicsPreliminary or mixed

  Studied for thinking and memory; results are limited, mixed or null depending on herb and group.

• Huperzine A and other herbal cholinesterase productsPreliminary or mixed

  Trials looked at thinking scores in Alzheimer's disease; evidence is weak and mixed.

• St. John's wortClinically supported

  Studied for mild to moderate depression; the way it works in the brain is not covered by the sources read, so this is about the condition, not a proven mechanism.

• HorsetailDocumented risk

  Thiamine destruction by thiaminase can contribute to brain damage in people who are already thiamine deficient, per the Canadian position cited by EMA.

• EucalyptusDocumented risk

  Swallowed eucalyptus oil can cause seizures and coma; this is a poisoning risk, not a benefit.

• WormwoodDocumented risk

  Thujone acts on the brain's GABA receptors; seizures are the main acute effect in animal studies.

• Blue lotusDocumented risk

  Case reports describe confusion, sedation and perceptual changes after vaping or an infusion of blue lotus. No benefit for the brain was shown in people.

• Blue cohoshDocumented risk

  Newborn (perinatal) stroke has been reported after maternal use near delivery in case reports; the link is not proven.

• HyssopDocumented risk

  Hyssop essential oil is described as toxic to the nervous system and linked to seizures (e-lactancia); a 1999 report links several essential oils to seizures. Avoid the oil, especially with epilepsy.

• Lion's manePreliminary or mixed

  Small trials in older adults with mild cognitive impairment reported higher test scores than placebo; trials in healthy young adults were mixed. Products and trials differ, so this is promising but limited.

• Graviola (soursop)Documented risk

  Annonacin damaged nerve cells in the lab and brain regions in rats, and mice showed tau build-up after a year of juice; relevance to people is unclear.

• PennyroyalDocumented risk

  Published poisoning cases include seizures, brain swelling and severe epilepsy after exposure, including two infants.

• YohimbeDocumented risk

  Anxiety, seizures and a reported brain bleed are described; cause not proven for the bleed.

• Mucuna pruriens (velvet bean)Preliminary or mixed

  Levodopa from the seed is turned into dopamine in the brain; trials were in Parkinson's only and were small.

• NutmegDocumented risk

  Large amounts can cause delirium and an altered level of consciousness.

• MaceDocumented risk

  A child who ate six dried pieces of mace became very drowsy and stiff; large amounts of mace or nutmeg can affect the nervous system. This is not about cooking amounts.

• False MorelDocumented risk

  Seizures and coma are described in severe, mostly fatal, cases; the mechanism involves lowered GABA in the brain.

• MayappleDocumented risk

  Confusion, lethargy, seizures and coma are reported (IPCS).

• LycheeDocumented risk

  Children in the 2014 outbreak had seizures or altered consciousness; hypoglycin A and MCPG were found in fruit and urine.

• Sage TeaDocumented risk

  Thujone seizure risk at high amounts.

• Star Anise TeaDocumented risk

  Seizure-like episodes and abnormal eye movements were reported in infants after star anise tea.

• Kava, Kratom and Blue Lotus TeasDocumented risk

  Sedation and altered mental state are described for kratom (FDA) and blue lotus (case series).

• Wormwood Tea (Dangers)Documented risk

  Thujone acts on the brain's GABA receptors and can cause seizures.

• Multi-Ingredient Brain FormulasPreliminary or mixed

  The target of these products; human evidence is mixed and ingredient-specific.

• L-theaninePreliminary or mixed

  Trials measured thinking and attention tasks, which are brain functions; effects were short-term and not consistent across tests.

• Fish oilPreliminary or mixed

  The brain is rich in DHA and the NHS notes omega-3 supports a baby's nervous system development. Extra fish oil in adults has only early, mixed evidence for cognition.

• Coenzyme Q10Deficiency link

  Primary CoQ10 deficiency can cause seizures, coordination problems and intellectual disability (rare inherited condition). Not shown to help Parkinson's disease.

• PhosphatidylserinePreliminary or mixed

  Research on supplemental PS focuses on memory in older adults; results are mixed and often from combination products.

• RosemaryPreliminary or mixed

  Memory and thinking scores improved in two small trials; animal work suggests possible mechanisms but this is not proven in people.

• SagePreliminary or mixed

  One small study in 20 healthy older adults found better memory and attention after a single amount of a standardised extract. Evidence is limited.

• California poppyLab or animal research only

  Sedative and anxiety-like-behaviour changes in mice suggest an effect on brain receptors; not shown in people.

• Asian ginsengPreliminary or mixed

  Small research on attention and thinking in middle-aged adults.

• Panax notoginsengPreliminary or mixed

  Injection added to standard care for acute bleeding in the brain gave better outcomes in a meta-analysis. These findings are for a hospital injection used with standard care, not supplements.

• Red cloverLab or animal research only

  Isoflavone extracts protected human nerve cells in the laboratory; not tested for benefit in people.

• GuaranaPreliminary or mixed

  Caffeine-containing guarana had a small effect on thinking speed in healthy adults.

• Wild lettuceDocumented risk

  Reduced consciousness, hallucinations and agitation were reported in poisoning cases.

• Muira puamaLab or animal research only

  In mice and rats, muira puama extracts affected memory, mood-like behavior and nerve-cell survival. No human trial was found.

• MaitakePreliminary or mixed

  One small strain-specific trial of cognition in healthy older adults.

• TremellaPreliminary or mixed

  One small 8-week trial in adults with memory complaints reported benefit versus placebo; it needs repeating.

• Magnolia barkLab or animal research only

  In lab cells honokiol and magnolol strengthen the brain's calming GABA-A signal; this does not show a benefit in people and is why sedative interactions are expected.

• GuayusaPreliminary or mixed

  Task and self-rated focus changes in small trials; not a structural or lasting effect.

• Gastrodia (tian ma)Preliminary or mixed

  The trials we found (migraine, delirium after surgery) tested gastrodin, the purified compound; evidence is limited and not shown for the whole herb.

• ShankhpushpiLab or animal research only

  Brain-related effects are reported in cell and animal studies only.

• Horseradish and wasabiPreliminary or mixed

  One small wasabi extract trial reported better memory in older adults.

• Sarpagandha (Indian snakeroot)Documented risk

  Mood and movement effects are described for reserpine on its label and in a case report.

• Malkangani (intellect tree)Lab or animal research only

  Malkangani seed oil improved memory in rats with a drug-induced deficit. No published human results were found, so benefit in people is not shown.

• Oat straw (milky oats)Preliminary or mixed

  Studied for thinking test performance; results are mixed.

• Sophora flavescens (ku shen)Documented risk

  Matrine caused brain tissue changes in mice; no human data found.

• BlueberriesPreliminary or mixed

  Episodic memory improved in older adults with mild cognitive decline in a meta-analysis; blood flow to the brain did not change in one trial.

• Lettuce (Romaine & Leaf)Preliminary or mixed

  Higher green leafy vegetable intake was linked to slower cognitive decline in one cohort of older adults; observational and not specific to lettuce.

• Golden thread cordycepsLab or animal research only

  Rat memory work with a methanol extract of cultured mycelium; nothing in people.

• Black horehoundDocumented risk

  Lab data show binding to dopamine, benzodiazepine and opioid receptors; RxList advises caution in Parkinson's disease and psychotic disorders.

• Chinese arborvitae seed (bai zi ren)Lab or animal research only

  Brain chemistry changes were seen in mice only.

• Tender nesting polyporeDocumented risk

  A 2025 review lists the fungus among those linked to delayed encephalopathy; only case-level neurological signs were seen in the report we read.

• MCT OilPreliminary or mixed

  Brain ketone uptake roughly doubled in a small Alzheimer disease trial.

• Energy DrinksLab or animal research only

  Animal studies raise concern for the adolescent brain; no human trials in the sources we read.

• Potassium AlumDocumented risk

  Encephalopathy (confusion, seizures) reported after alum bladder irrigation, a hospital procedure.

• Creatine NitratePreliminary or mixed

  One small trial found a thinking-test change only when taken with caffeine.

• MultivitaminsPreliminary or mixed

  Mixed results on thinking tests; a COSMOS blood-marker study (abstract read) found no difference in three brain-injury markers.

• Women's and Men's MultivitaminsPreliminary or mixed

  Small cognitive benefit in one 3-year trial of older adults; see the brain-health note.

• Multivitamins for Adults Over 50Preliminary or mixed

  Episodic memory scores were better with a multivitamin-mineral in COSMOS-Web.

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