Vitamin B6 (Pyridoxine HCl)
Also known as: Pyridoxine, Vitamin B6
Systematic reviews and clinical guidelines note that interventional trial data for vitamin B6 are limited and of low quality for many symptomatic indications (for example, leg cramps and premenstrual syndrome), with no consistent, high‑quality evidence of benefit reported in the provided abstracts. In contrast, guideline evidence supports oral pyridoxine responsiveness and therapeutic use in a subset of patients with cystathionine beta‑synthase deficiency. Neonatal seizure guidance also recommends that a trial of pyridoxine may be considered in infants with seizures, though this is a consensus recommendation where evidence is limited.
Last reviewed: 2026-10-14 · 5 indexed studies
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Overview
Vitamin B6 (pyridoxine) is a water‑soluble B vitamin used to prevent or treat deficiency and as adjunctive therapy in several clinical conditions. Evidence from systematic reviews and guidelines indicates limited and mixed trial data for common symptomatic uses, but clear clinical benefit in pyridoxine‑responsive genetic disorders such as some forms of cystathionine beta‑synthase deficiency.
Mechanism & Function
Mechanism of Action
Acts as a cofactor (pyridoxal‑5‑phosphate) for enzymes involved in amino acid metabolism, neurotransmitter synthesis, and transsulfuration pathways; this underlies its role in homocysteine metabolism and influences neurotransmitter levels relevant to seizure thresholds and mood regulation.
Physiological Role
Cofactor in amino acid metabolism and neurotransmitter synthesis; important in methionine catabolism and homocysteine metabolism where responsiveness to pyridoxine can occur in specific genetic defects.
Primary Pathways
Performance / Health Relevance
No robust evidence from the provided abstracts supports use of vitamin B6 to improve exercise performance. Its primary performance‑relevant roles would be indirect, via correction of deficiency affecting general health or neuromuscular function.
Evidence Review
Compare Vitamin B6 Forms
Full comparison2 vitamin b6 forms are indexed. Bioavailability, clinical evidence, and best-use cases differ meaningfully between them.
| Form | Evidence |
|---|---|
Vitamin B6 (Pyridoxine HCl)This page Pyridoxine HCl is a commonly used oral form that is converted to the active cofactor pyridoxal‑5‑phosphate in the body. | 63/100 |
| Vitamin B6 (Pyridoxal-5-Phosphate / P5P) P5P is often considered more bioavailable than pyridoxine HCl as it bypasses the need for liver conversion. However, absorption can vary with gastrointestinal health. | 65/100 |
Practical Use & Dosage
- Minimum Effective Dose
- Not established from provided abstracts
- Optimal Range
- Not established from provided abstracts
- Upper / Caution Level
- Guidance from authoritative sources commonly sets an upper limit around 100 mg/day for adults to reduce risk of sensory neuropathy (use with caution)
- Timing
- Not established from provided abstracts
- Best Format
- Oral pyridoxine hydrochloride
- Bioavailability
- Pyridoxine HCl is a commonly used oral form that is converted to the active cofactor pyridoxal‑5‑phosphate in the body.
- Absorption Considerations
- Not detailed in provided abstracts
Safety & Interactions
Side Effects
- •Gastrointestinal upset (reported in general use)
- •High‑dose chronic use associated with sensory neuropathy (noted as potential toxicity in guideline abstract)
Contraindications
- No specific contraindications provided in the abstracts
Drug Interactions
- •Not detailed in provided abstracts
Who Should Avoid
- •People with known hypersensitivity to pyridoxine
- •Use caution in high‑dose chronic supplementation because of neuropathy risk
Monitoring
In specialised clinical settings (for example CBS deficiency) monitor plasma homocysteine and clinical response; monitor for sensory neuropathy if using high doses long term.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Vitamin B6 (Pyridoxine HCl) typically used or indicated?
Vitamin B6 (Pyridoxine HCl) is most commonly used for: Correcting or preventing deficiency, Support for homocysteine metabolism in specific genetic disorders, Adjunctive trial therapy for certain neonatal seizures, Symptom relief in conditions such as premenstrual syndrome or leg cramps (investigational). Cofactor in amino acid metabolism and neurotransmitter synthesis; important in methionine catabolism and homocysteine metabolism where responsiveness to pyridoxine can occur in specific genetic defects.
How does Vitamin B6 (Pyridoxine HCl) work?
Acts as a cofactor (pyridoxal‑5‑phosphate) for enzymes involved in amino acid metabolism, neurotransmitter synthesis, and transsulfuration pathways; this underlies its role in homocysteine metabolism and influences neurotransmitter levels relevant to seizure thresholds and mood regulation.
What is the recommended dose of Vitamin B6 (Pyridoxine HCl)?
The optimal range is Not established from provided abstracts. with a minimum effective dose of Not established from provided abstracts. Best taken: Not established from provided abstracts. Upper / caution level: Guidance from authoritative sources commonly sets an upper limit around 100 mg/day for adults to reduce risk of sensory neuropathy (use with caution).
What are the side effects of Vitamin B6 (Pyridoxine HCl)?
Reported side effects include: Gastrointestinal upset (reported in general use); and High‑dose chronic use associated with sensory neuropathy (noted as potential toxicity in guideline abstract). Monitoring: In specialised clinical settings (for example CBS deficiency) monitor plasma homocysteine and clinical response; monitor for sensory neuropathy if using high doses long term.
Does Vitamin B6 (Pyridoxine HCl) interact with medications?
Known or theoretical interactions: Not detailed in provided abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid Vitamin B6 (Pyridoxine HCl)?
Vitamin B6 (Pyridoxine HCl) is generally not recommended for: People with known hypersensitivity to pyridoxine; Use caution in high‑dose chronic supplementation because of neuropathy risk; and No specific contraindications provided in the abstracts.
How strong is the evidence for Vitamin B6 (Pyridoxine HCl)?
Evidence level: Moderate (overall score 63/100), based on 5 indexed studies on SuppIndex.
Research & References (5)
ESPEN micronutrient guideline.
ESPEN guideline on micronutrients reviewed available physiological, observational and interventional data for multiple micronutrients including vitamin B6 and produced practice recommendations; authors noted a limited number of interventional trials and a generally low level of evidence.
Leg cramps.
Systematic review of treatments for idiopathic and pregnancy‑related leg cramps included vitamin B6 among evaluated interventions but the abstract does not report convincing positive results; overall quality was assessed with GRADE and evidence was summarised alongside other interventions.
Premenstrual syndrome.
Systematic review of interventions for premenstrual syndrome listed pyridoxine among many evaluated treatments; the review highlights difficulties synthesising data due to heterogenous symptom scales and trial designs.
Guidelines for the diagnosis and management of cystathionine beta-synthase deficiency.
Guidelines for cystathionine beta‑synthase deficiency state that some mildly affected patients respond to pyridoxine and that pyridoxine responsiveness should be tested; maintaining lower plasma homocysteine concentrations is recommended to reduce complications.
Treatment of seizures in the neonate: Guidelines and consensus-based recommendations-Special report from the ILAE Task Force on Neonatal Seizures.
ILAE neonatal seizure guidelines recommend that a trial of pyridoxine may be attempted in neonates presenting with seizures (consensus where evidence was limited), as part of a diagnostic and therapeutic approach.
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Research Overview
Moderate EvidenceCite this ingredient
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Stable URL
https://thesuppindex.com/ingredients/vitamin-b6-pyridoxine-hcl
SuppIndex. (2026). Vitamin B6 (Pyridoxine HCl): Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/vitamin-b6-pyridoxine-hcl
Based on 5 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
Commonly included in multivitamin/mineral products; caution with other high‑dose B6 sources to avoid excessive total intake.