B-Complex
Also known as: B vitamins, vitamin B complex
Recommended Dosage
1–1 capsule
B vitamins are a group of eight water-soluble vitamins that play essential roles in cellular metabolism, energy production, and nervous system function. While individual B vitamins have specific roles — B12 for nerve health, folate for DNA synthesis, B6 for neurotransmitter production — they often work synergistically. Methylated forms (methylfolate, methylcobalamin) are preferred as they bypass the MTHFR enzyme pathway that up to 40% of the population has reduced function in.
TL;DR: Group of essential vitamins for energy metabolism, nervous system function, and mood. Methylated forms preferred for MTHFR variants.
Evidence
Grade B
Studies
3
Interactions
3
Forms
1
Evidence Rating: Grade B — Moderate Evidence
Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.
Interaction Warnings
B6 >200mg/day can reduce levodopa effectiveness
Metformin depletes B12; supplement at least 1,000mcg/day
Reduce B12 absorption; supplement
⚠️ Important Notes
- Look for methylated forms (methylfolate, methylcobalamin)
- B2 may cause bright yellow urine — normal and harmless
- B6 >200mg/day long-term: peripheral neuropathy risk
Clinical Evidence (3 studies)
B vitamins and the brain: mechanisms, dose and efficacy
Kennedy DO (2016) — Nutrients
All B vitamins play essential roles in brain function; supplementation benefits even without deficiency
View on PubMedB vitamins reduced homocysteine by 26%
Clarke R et al. (2007) — Arch Intern Med
B12+B9+B6 reduced homocysteine; cardiac risk marker
View on PubMedB12 deficiency: neurological and cognitive consequences
O'Leary F & Samman S (2010) — Nutrients
Deficiency causes neurological damage; supplementation critical
View on PubMedAlternatives to Consider
These supplements target similar goals and may be worth considering alongside or instead of B-Complex.
Vitamin B6
Grade AEssential coenzyme for neurotransmitter synthesis (serotonin, GABA, dopamine). Strong evidence for PMS. Deficiency common in those on OCP or with poor diet.
Omega-3 Fish Oil
Grade AEssential fatty acids with strong evidence for cardiovascular and mental health. EPA-dominant for mood; triglyceride form for absorption.
Vitamin B12
Grade ACritical for nerve function, DNA synthesis, and red blood cell formation. Vegans, elderly, and metformin users are at high risk of deficiency. Methylcobalamin preferred for neurological benefit.
Related Supplements
Vitamin B6
Grade A — Strong EvidenceEssential coenzyme for neurotransmitter synthesis (serotonin, GABA, dopamine). Strong evidence for PMS. Deficiency common in those on OCP or with poor diet.
Vitamin B12
Grade A — Strong EvidenceCritical for nerve function, DNA synthesis, and red blood cell formation. Vegans, elderly, and metformin users are at high risk of deficiency. Methylcobalamin preferred for neurological benefit.
Folate (Vitamin B9)
Grade A — Strong EvidenceEssential for DNA synthesis, methylation, and mood regulation. ~40% of people have MTHFR variants reducing conversion — use methylfolate. Always pair with B12.
Omega-3 Fish Oil
Grade A — Strong EvidenceEssential fatty acids with strong evidence for cardiovascular and mental health. EPA-dominant for mood; triglyceride form for absorption.
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⚕️ Important Disclaimer
This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.
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