Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence – Narrative Review

Dosage: Varies by study.
Thiamine (B1): 100 mg/day for 3 days
Riboflavin (B2): 2–4 mg/day for 8 weeks, or 100 mg before/during endurance exercise
Pantothenic acid (B5): 2 g/day for 2 weeks (older trial)
Folate (B9): 1 mg/day for 3 months (children), 400–800 µg/day for adults in trials
Outcome: Supplementation with B vitamins and other nutrients can reduce symptoms of physical and mental fatigue and improve energy, especially when there is a deficiency or low status.
Summary: Supplementing with B vitamins and key minerals helps fight tiredness, low mood, and poor mental function, especially in people who are lacking these nutrients.

Read more

 A functional evaluation of anti-fatigue and exercise performance improvement following vitamin B complex supplementation in healthy humans – Randomised Controlled Trial

Dosage: 1 tablet daily (Vitamin B1 33.6 mg, B2 10 mg, B6 50 mg, B12 750 μg and other nutrients) for 28 days
Outcome: Improvements in running time to exhaustion, blood lactate, and blood ammonia during and after exercise
Summary: 28 days of vitamin B complex significantly improved exercise endurance and reduced fatigue, with lower blood lactate and ammonia compared to placebo.

Read more

 Vitamin B status in patients with chronic fatigue syndrome – Observational Study

Dosage: N/A (study assessed natural vitamin status, no supplementation given)
Outcome: Basal and activated enzyme activities for B6, B2 and B1 were lower in CFS patients than healthy controls
Summary: People with chronic fatigue syndrome had lower functional levels of certain B vitamins, suggesting a possible link between B vitamin status and fatigue symptoms.

Read more

B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis lifespan – Meta-analysis
Dosage: B vitamin supplementation (varied doses of folate, B6, B12; intervention periods mostly over 12 months)
Outcome: Slowed cognitive decline and reduced dementia risk, especially with higher folate intake and longer supplementation
Summary: Supplementing with B vitamins—especially folate—can help slow down age-related cognitive decline and may lower the risk of dementia if started early and continued long-term.

Read more

 B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review – Review
Dosage: Varies; review suggests benefits from multi-B vitamin supplementation at doses well above the RDA (often 2–10x RDA or more, depending on the vitamin and individual needs).
Outcome: Effects of B vitamins on neurological health, especially cognitive function.
Summary: Supplementing with all B vitamins (not just B6, B9, and B12) at higher than standard doses may best support brain health and potentially help to lower the risk of developing age related brains disorders.

Read more

 Could Vitamins Have a Positive Impact on the Treatment of Parkinson’s Disease? lifespan – Review

Dosage: Varies by B vitamin; examples include 100–200 mg thiamine (B1) daily (IM), dietary B3 (niacinamide/nicotinamide), B6 from food/supplement, and B12 as part of a multivitamin or by injection
Outcome: Association between B vitamin supplementation and protection against neurodegeneration in Parkinson’s disease
Summary: Multiple B vitamins may help protect the brain in Parkinson’s disease, mainly by reducing oxidative stress, inflammation, and cell death in nerve cells.

Read more

Vitamin B1 (Thiamine) – Review

Dosage: 1.1–1.2 mg daily for adults (RDI); higher doses (e.g. 100 mg IV/IM) used for deficiency or clinical treatment
Outcome: Prevents and treats symptoms of thiamine deficiency including neurological and heart issues
Summary: Thiamine is vital for energy production and nerve function. Deficiency can cause fatigue, nerve problems, heart failure, and serious brain disorders, but supplementation is safe and effective at reversing symptoms if caught early.

Read more

 Vitamin B2 (Riboflavin) – Review

Dosage: Typical supplementation is 50–100 mg daily; recommended daily allowance is 0.9–1.3 mg/day for adults, 400 mg/day for migraine prevention, ophthalmic use as 0.146% solution.
Outcome: Prevents and treats deficiency symptoms; used for migraine prevention and eye health.
Summary: Riboflavin is essential for energy production and healthy metabolism. Supplementation corrects deficiency and can help prevent migraines and manage certain eye conditions.

Read more

 Vitamin B3 (Niacin) – Review

Dosage: Typical adult dose: 13–20 mg/day (dietary requirement)
Outcome: Manages cholesterol and triglyceride levels; treats and prevents niacin deficiency (pellagra).
Summary: Niacin is essential for energy production and cell metabolism, and at high doses can lower cholesterol and triglycerides. Side effects and risks increase with high doses.

Read more

 Vitamin B5 (Pantothenic Acid) lifespan – Review

Dosage: Common adult dosage is 5 mg/day; supplements range from 10–1000 mg/day. For cholesterol-lowering: pantethine 600 mg/day for 8 weeks, then 900 mg/day for 8 weeks.
Outcome: Supports energy metabolism, hormone production, healthy skin, and cholesterol management; deficiency is rare.
Summary: Vitamin B5 helps the body turn food into energy, make hormones, and maintain healthy skin, hair, and nerves. High doses of pantethine may help lower cholesterol in some people.

Read more

 Vitamin B6 (Pyridoxine) – Review
Dosage: 10–20 mg daily for deficiency (injection), then 2–5 mg daily (oral) for maintenance
Outcome: Helps prevent and treat vitamin B6 deficiency and related conditions; supports metabolism and nerve function
Summary: Vitamin B6 is essential for over 100 enzymes in the body, mainly helping with metabolism, brain health, and making neurotransmitters. It is safe at usual doses, but very high doses over time can cause nerve problems.

Read more

 Vitamin B7 (Biotin) – Review
Dosage: 5– 500 mcg micrograms daily for deficiency, pregnancy, or breastfeeding.
Outcome: Biotin supports healthy hair, nails, skin, and energy metabolism.
Summary: Biotin is essential for breaking down food into energy and is important for healthy hair, nails, and nerves. Supplementation only helps if you are deficient; benefits for healthy people are unproven.

Read more

 Vitamin B9 (Folic Acid) – Review
Dosage: 400 mcg daily for adults (typical); 400–800 mcg daily to prevent neural tube defects in pregnancy; 1–5 mg daily for anaemia or deficiency; up to 15 mg daily in special cases
Outcome: Prevents and treats folate deficiency, neural tube defects, and certain types of anaemia
Summary: Folic acid is essential for DNA production, red blood cell formation, and lowering homocysteine levels. Supplementation is especially important before and during pregnancy to prevent birth defects, and in treating megaloblastic anaemia.

Read more

 Vitamin B12 (Cobalamin) – Review
Dosage: Oral daily 1–2 mg. Doses may vary by deficiency severity and cause.
Outcome: Prevention and treatment of vitamin B12 deficiency and related health conditions.
Summary: Vitamin B12 is vital for making red blood cells and keeping nerves healthy. Deficiency can cause anaemia and nerve problems; supplementation quickly corrects blood and neurological symptoms.

Read more

B Vitamins: Functions and Uses in Medicine – Review

Dosage: Varies based on each B vitamin.
B1 (Thiamine): 1.2 mg (men), 1.1 mg (women)
B2 (Riboflavin): 1.3 mg (men), 1.1 mg (women)
B3 (Niacin): 16 mg (men), 14 mg (women)
B5 (Pantothenic Acid): 5 mg
B6 (Pyridoxine): 1–1.7 mg
B7 (Biotin): 30 mcg
B9 (Folate): 400 mcg
B12 (Cobalamin): 2.4 mcg
Outcome: Disucsses how B vitamins support essential cellular processes and the effects of deficiency.
Summary: B vitamins help the body produce energy, make new cells, support DNA/RNA synthesis, and keep enzymes working properly. Deficiency in any B vitamin can harm cell function but is reversible with proper supplementation.

Read more

‘Niacin Cures Systemic NAD+ Deficiency and Improves Muscle Performance in Adult-Onset Mitochondrial Myopathy’ lifespan – Open-label Human Intervention Study

Dosage: Niacin (vitamin B3), gradually increased from 250 mg/day up to 750–1,000 mg/day, for 4–10 months
Outcome: NAD+ levels in blood and muscle, muscle strength, liver fat, and mitochondrial function
Summary: High-dose niacin boosted NAD+ levels up to 8-fold, improved muscle strength, reduced liver fat, and increased mitochondrial biogenesis in adults with mitochondrial myopathy.

Read more

 Niacin: an old lipid drug in a new NAD+ dress – Review

Dosage: N/A (Mechanisms discussed; not a clinical intervention study)
Outcome: How niacin affects lipid metabolism and NAD+ levels
Summary: Niacin (vitamin B3) helps lower bad fats and raise good cholesterol, but also boosts NAD+, a key molecule for cell energy and repair. Boosting NAD+ may support healthy ageing through better fat metabolism and mitochondrial health.

Read more

A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and ‘At-Risk’ Individuals – Systematic Review and Meta-Analysis

Dosage: Supplements contained at least 3 B vitamins (typically B6, B12, folate; doses ranged from 1–300x daily recommended intake; most studies used B vitamin complexes as part of a multivitamin, given daily for 4 weeks to 2 years)
Outcome: Impact on stress, depressive symptoms, and anxiety in healthy and ‘at-risk’ adults
Summary: B vitamin supplementation reduced stress and anxiety in healthy or ‘at-risk’ people. Benefits were clearer for those with poor mood or low nutrient status at baseline.

Read more

 Dietary intake of B vitamins and their association with depression, anxiety, and stress symptoms – Cross-sectional Study

Dosage: Varied daily dietary intake of B vitamins (thiamine, niacin, pantothenic acid, B6, biotin, folic acid); exact supplement doses not specified
Outcome: Association between B vitamin intake and symptoms of depression, anxiety, and stress
Summary: Higher intake of B vitamins, especially biotin and B6, was linked to fewer symptoms of depression, anxiety, and stress.

Read more

 Associations of depression and intake of antioxidants and vitamin B complex: Results of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) lifespan – Cross-sectional study

Dosage: Dietary intake levels of vitamin B6, folate (B9), and vitamin B12 (amounts assessed by food frequency questionnaire; no supplement doses reported)
Outcome: Relationship between dietary intake of B vitamins and depression
Summary: People with higher intakes of vitamin B6, B9, and B12 from food had lower rates and severity of depression, especially women.

Read more

Dietary Vitamin B Complex: Orchestration in Human Nutrition throughout Life with Sex Differences – Review

Dosage: Varies by vitamin, age, sex, and life stage
Outcome: Reviews how B vitamin needs, effects, and risks of deficiency change across life and differ by sex.
Summary: B vitamins are needed at every age for energy, brain, and body health. Needs rise during pregnancy, growth, and ageing. Deficiency at any stage can cause serious health issues, so a balanced diet and, if needed, supplements are important.

Read more