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Pyritinol (Pyrithioxine / Encephabol)

Synthetic — disulfide-linked pyridoxine dimer
Evidence Level
Limited
3 Clinical Trials
6 Documented Benefits
2/5 Evidence Score

Pyritinol (also called pyrithioxine, marketed as Encephabol®) is a compound consisting of two vitamin B6 (pyridoxine) molecules linked by a disulfide bridge. Developed by Merck Laboratories in 1961, it's approved in several European countries (Austria, Germany, France, Italy, Portugal, Greece) for chronically impaired brain function in dementia and craniocerebral trauma sequelae. France additionally approves pyritinol as a disease-modifying antirheumatic drug (DMARD) for rheumatoid arthritis. Trials in inpatients with senile dementia (Alzheimer type and multi-infarct) showed significant cognitive improvements at 600 mg/day. The honest framing: a European prescription drug with reasonable evidence for cognitive support in dementia syndromes and unique anti-inflammatory DMARD effects in rheumatoid arthritis; sold as a nootropic supplement in the US since the early 1990s but not FDA-approved. Approach with realistic expectations: this is a pharmaceutical-grade compound with specific therapeutic indications, not a casual nootropic.

Studied Dose Dementia 200 mg 3×/day (600 mg/day); rheumatoid arthritis 200-600 mg/day; nootropic 200-600 mg/day split.
Active Compound Pyritinol (pyrithioxine, pyridoxine disulfide) — two pyridoxine (B6) molecules joined by a disulfide bridge.

Benefits

Senile dementia cognitive support

Senile dementia cognitive support: a 12-week double-blind randomized trial in inpatients with mild-to-moderate dementia (Alzheimer type or multi-infarct) at 600 mg/day showed significant improvements over placebo on cognitive performance tests, clinical global impression, and EEG measures of vigilance. Foundational evidence supporting European regulatory approvals.

Supported by Trial 1, Trial 2

Sustained long-term cognitive benefit

Sustained long-term cognitive benefit: a long-term double-blind crossover study in dementia patients with regional cerebral blood flow measurements showed pyritinol's beneficial cognitive effects sustained during 1-year follow-up. Limited by small sample but supports durability of effects observed in shorter trials.

Supported by Trial 3

Rheumatoid arthritis (DMARD approval)

Rheumatoid arthritis (DMARD approval): France approves pyritinol as a disease-modifying antirheumatic drug for rheumatoid arthritis. A European multicenter study compared pyritinol with auranofin (gold therapy) and found comparable efficacy. Mechanism involves disulfide bridge SH-group anti-inflammatory effects — distinguishes pyritinol from typical nootropics.

Supported by Trial 2

Pediatric learning disabilities (European approval)

Approved in Germany and other European countries for pediatric learning disabilities, developmental dysphasia, postnatal hypoxia, and other pediatric cognitive disorders. Older studies showed effects on behavior and intellectual functioning in learning-disabled children. Older but supportive evidence base.

Supported by Trial 2

Cerebral metabolism enhancement

Pyritinol HCl improves cerebral blood flow and oxidative metabolism in patients with dementia. Mechanism for cognitive improvements via enhanced cerebral oxygen and glucose utilization — pharmacologically classified among cerebral metabolic enhancers for dementia treatment.

Supported by Trial 2, Trial 3

Hangover prevention (historical evidence)

An older double-blind comparison versus placebo showed pyritinol benefit in preventing alcohol-induced hangover symptoms. Limited modern replication but interesting historical use case for acute alcohol-induced cognitive and somatic symptoms.

Supported by Trial 3, Trial 2

Mechanism of action

1

Vitamin B6 (pyridoxine) delivery via disulfide cleavage

In vivo, disulfide bridge cleaves to release two molecules of pyridoxine (vitamin B6) — providing B6 substrate for amino acid metabolism, neurotransmitter synthesis (GABA, dopamine, serotonin via PLP coenzyme), and other B6-dependent functions. Mechanism for general neuroprotection.

2

BBB penetration via disulfide structure

Crosses BBB much more readily than pyridoxine itself due to disulfide structure providing lipophilicity. Accumulates in gray matter regions including hippocampus, cerebral nuclei, cerebellum, cortex. Mechanism for CNS effects beyond simple B6 supplementation.

3

Antioxidant activity via SH groups

Disulfide bridge can be reduced to two SH groups, providing antioxidant activity. Pyritinol shown to scavenge hydroxyl radicals. Mechanism for neuroprotection in ischemia and aging-related oxidative stress.

4

Cholinergic enhancement (without direct receptor binding)

Pyritinol enhances acetylcholine release without directly interacting with cholinergic receptors. Mechanism more complex than typical AChE inhibitors — involves membrane fluidity and lipid solubility effects. Mechanism for cognitive effects in dementia.

5

Anti-inflammatory effects

Pyritinol has anti-inflammatory effects relevant to RA approval — likely via SH-group effects on inflammatory mediators and neutrophil function modulation. Distinguishes pyritinol from typical nootropics with documented systemic anti-inflammatory properties.

6

Plasma viscosity reduction and cerebral blood flow

Reduces plasma viscosity and improves cerebral blood flow. Mechanism for cognitive effects in vascular dementia and post-stroke contexts. Cerebral metabolic effects have been demonstrated in dementia patients.

Clinical trials

1
Pyritinol in SDAT/mid Pivotal Clinical Trial

Double-blind randomized placebo-controlled trial (Fischhof PK, Saletu B, Rüther E, Litschauer G, Möslinger-Gehmayr R, Herrmann WM 1992, Pharmacopsychiatry 25(6):205-209, doi:10.1055/s-2007-1014434).

183 inpatients screened, 164 met inclusion criteria, 156 completed trial. Senile Dementia of Alzheimer Type (SDAT) and Multi-Infarct Dementia (mid) of mild-moderate degree. Allocation by Hachinski Ischemic Score, CT scans, EEG. 12-week double-blind treatment phase: pyritinol 200 mg dihydrochloride-monohydrate 3x daily (600 mg/day) vs placebo. Confirmatory statistics included CGI item 2, Short Cognitive Performance Test, Sandoz Clinical Assessment Geriatric scale 'cognitive disturbances' factor.

Pyritinol statistically significantly superior to placebo on ALL 3 target variables. Clinical relevance underlined by descriptive variables and convergence at different observation levels. EEG mapping: pyritinol decreased slow activity, increased fast alpha and beta — reflecting improved vigilance. Foundational positive clinical trial supporting European regulatory approvals for chronically impaired brain function. One of more rigorous racetam-class dementia trials.

2
Pyritinol vs Auranofin in Rheumatoid Arthritis

European Multicenter Study Group clinical trial (Lemmel EM 1993, Br J Rheumatol 32(5):375-382, doi:10.1093/rheumatology/32.5.375).

Patients with rheumatoid arthritis randomized to pyritinol or auranofin (oral gold). Standard RA clinical and laboratory assessments.

Pyritinol showed comparable efficacy to auranofin (oral gold therapy) in rheumatoid arthritis. Foundational evidence supporting French regulatory approval as disease-modifying antirheumatic drug (DMARD). Distinguishes pyritinol from pure cognitive enhancers — has documented systemic anti-inflammatory and disease-modifying properties. Mechanism via SH-group anti-inflammatory effects.

3
Pyritinol Long-term in SDAT Cross-over

Double-blind cross-over trial (Hindmarch I, Coleston DM, Kerr JS 1990).

26 patients with clinical diagnosis of Senile Dementia of Alzheimer's type (SDAT). Randomly assigned in double-blind cross-over trial pyritinol vs placebo. Long-term follow-up 1 year. Psychiatric/neurological exam, psychometric testing, regional cerebral blood flow.

Pyritinol had beneficial effect on cognitive performance sustained during long-term follow-up of 1 year. Memory performance improvement on battery of 7 tests with repeated 300 mg daily doses. Limited by small sample but important for demonstrating durability of effects. Supports clinical use for chronic dementia indications where sustained benefit matters.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated; long-term clinical use in Europe supports safety profile.
Mild GI upset (nausea, abdominal discomfort).
Skin reactions (rash, pruritus) — more frequent than other racetams.
Headache.
Rare but serious: hepatic injury, taste disturbances, pancreatitis, lupus-like syndrome reported with chronic use.
Pregnancy/lactation: avoid (insufficient data despite B6 origin).
Renal impairment: caution.
Long-term safety: moderate European clinical use data.

Important Drug interactions

Levodopa: theoretical reduction of efficacy (B6 effect on peripheral decarboxylation — particularly relevant when not combined with carbidopa).
Penicillamine: theoretical interactions in rheumatoid arthritis combination therapy.
Other DMARDs (gold, methotrexate): combination not standard but possible.
Anticoagulants: limited interaction data.
Most medications: compatible at typical doses.
B6-related: monitor in patients with vitamin B6-related conditions.

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Frequently asked questions about Pyritinol (Pyrithioxine / Encephabol)

What is pyritinol?

Pyritinol is a synthetic compound made of two vitamin B6 molecules joined together, used as a nootropic for cognition and studied in some countries as a medicine for memory and mood. It is not an approved US supplement or drug.

What is pyritinol used for?

It has been studied for cognitive support, including age-related decline, and is sometimes used for mental energy and hangover recovery in community use. Evidence is older and limited.

How much pyritinol is used?

Research and community doses are often around 600 mg per day or more, split. Quality and legal status vary, so caution is warranted.

Is pyritinol safe?

Short-term use is generally reported as tolerated, but rare reports include liver and skin reactions. Long-term self-directed use is uncertain, and it is not an approved US supplement, so consult a healthcare professional.

What is the recommended dosage of Pyritinol?

The clinically studied dose is Dementia 200 mg 3×/day (600 mg/day); rheumatoid arthritis 200-600 mg/day; nootropic 200-600 mg/day split. Always follow the product label and check with a healthcare provider for personal advice.

Is Pyritinol safe, and does it have side effects?

For most healthy adults, Pyritinol is well tolerated at studied doses. Reported effects can include: Generally well-tolerated; long-term clinical use in Europe supports safety profile. Mild GI upset (nausea, abdominal discomfort). It may also interact with some medications. Pyritinol is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Pyritinol interact with any medications?

Possible interactions include: Levodopa: theoretical reduction of efficacy (B6 effect on peripheral decarboxylation — particularly relevant when not combined with carbidopa). Penicillamine: theoretical interactions in rheumatoid arthritis combination therapy. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Pyritinol?

NutraSmarts rates the evidence for Pyritinol as Limited (2 out of 5). It is backed by 3 clinical trials and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Fischhof PK, Saletu B, Rüther E, Litschauer G, Möslinger-Gehmayr R, Herrmann WM Therapeutic efficacy of pyritinol in patients with senile dementia of the Alzheimer type (SDAT) and multi-infarct dementia (MID) Neuropsychobiology. 1992;26(1-2):65-70. doi:10.1159/000118898.PubMedUsed to support: Placebo-controlled trial of pyritinol 600 mg/day in Alzheimer-type and multi-infarct dementia patients; significant improvements in cognitive and global assessments, supporting the senile dementia cognitive support and cerebral metabolism enhancement benefits.
  2. Knezevic S, Mubrin Z, Risberg J, Vucinic G, Spilich G, Gubarev N, Wannenmacher W Pyritinol treatment of SDAT patients: evaluation by psychiatric and neurological examination, psychometric testing and rCBF measurements Int Clin Psychopharmacol. 1989;4(1):25-38.PubMedUsed to support: Clinical trial evaluating pyritinol in Alzheimer-type dementia using psychiatric, neurological, psychometric, and regional cerebral blood flow (rCBF) measurements; supports both cognitive benefit and the cerebral metabolism/circulation mechanism.
  3. Lemmel EM Comparison of pyritinol and auranofin in the treatment of rheumatoid arthritis. The European Multicentre Study Group Br J Rheumatol. 1993;32(5):375-82. doi:10.1093/rheumatology/32.5.375.PubMedUsed to support: European multicenter RCT comparing pyritinol to auranofin (gold salt) as a disease-modifying antirheumatic drug (DMARD) for rheumatoid arthritis; confirms pyritinol's DMARD approval indication in Europe.