Pyritinol (Pyrithioxine / Encephabol)

Synthetic — disulfide-linked pyridoxine dimer
Evidence Level
Preliminary
3 Clinical Trials
6 Documented Benefits
1/5 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 has additionally licensed it as a prescription disease-modifying antirheumatic drug for rheumatoid arthritis. Those are national medicine approvals granted decades ago. The United States has never approved pyritinol as a drug, and it is not a recognised dietary ingredient either, so what is sold here is a gray-market drug. Two older trials in people with diagnosed dementia reported cognitive improvement: a 12-week placebo-controlled trial at 600 mg/day with 156 completers, and a crossover trial in 26 patients. Both treated diagnosed patients with a prescribed medicine; neither tells you anything about healthy users. The honest framing: this is a prescription medicine, not a dietary supplement, and its risks are drug sized. In the one-year rheumatoid arthritis trial, adverse events occurred in 64% of pyritinol patients and 44% stopped early. Published case reports describe severe cholestatic hepatitis and acute pancreatitis confirmed by controlled rechallenge. Treat it accordingly: where it is licensed, it is prescribed and monitored by a doctor, and self-directed use is not a low-risk experiment.

Studied Dose Dementia 200 mg 3×/day (600 mg/day); these are prescription doses under medical supervision, with no established dose for self-directed use.
Active Compound Pyritinol (pyrithioxine, pyridoxine disulfide) — two pyridoxine (B6) molecules joined by a disulfide bridge.

Benefits

What the dementia trial actually tested

This is prescription treatment of a diagnosed disease, not a supplement benefit. In a 12-week double-blind trial, 183 inpatients were screened, 164 entered and 156 finished. Pyritinol 200 mg three times a day (600 mg/day) beat placebo on all three prespecified measures: item 2 of the Clinical Global Impression, the Short Cognitive Performance Test, and the cognitive disturbances factor of the Sandoz geriatric scale. EEG mapping showed less slow activity and more fast alpha and beta, which the authors read as better vigilance. The trial dates from 1992 and has not been repeated. It does not show that pyritinol treats or slows Alzheimer's disease, and it says nothing about healthy people.

What the small crossover trial showed

There is no long-term evidence here. The crossover trial behind this section (Knezevic 1989) enrolled 26 patients with mild to moderate Alzheimer-type dementia and reported significant improvement in cognitive performance, plus a more normal blood flow response during mental activation. That paper reports no one-year follow-up and no durability data, so the claim that the effect lasted a year was not supported by the study cited for it.

Prescription rheumatoid arthritis use, not a joint supplement use

Pyritinol has been licensed in France as a prescription disease-modifying drug for rheumatoid arthritis, an autoimmune disease managed by specialists. The single trial cited here (Lemmel 1993) gave 600 mg/day for one year: response rates were 78% for pyritinol against 59% for oral auranofin, but adverse events occurred in 64% of pyritinol patients and 61 of 139 (44%) dropped out inside the year. None of that supports taking pyritinol for everyday joint comfort, and none of it is a reason to self-treat arthritis.

Pediatric claims with no citation

No study and no regulatory document is cited anywhere on this page for pediatric learning problems, developmental dysphasia or postnatal hypoxia, so treat these claims as unsupported. Whatever old national labels may have said, giving a prescription drug to a child is a medical decision that belongs with a doctor, and nothing here should be used to make it.

Cerebral blood flow in one small study

The only relevant measurement cited is regional cerebral blood flow in 26 patients with Alzheimer-type dementia, where pyritinol normalized the rise in blood flow during mental activation. Oxygen and glucose utilization were not measured in that study, so the broader cerebral metabolism claim is not backed by anything cited on this page.

Hangover claim with no citation

No study is cited anywhere on this page for hangover prevention, so this claim cannot be checked and should be treated as unsupported. Pairing a drug that has caused severe cholestatic hepatitis with heavy drinking is a poor idea in any case.

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. That is a proposed pathway from pharmacology work, not a demonstrated clinical effect.

2

BBB penetration via disulfide structure

Crosses BBB much more readily than pyridoxine itself due to disulfide structure providing lipophilicity. Animal distribution work reports accumulation in gray matter, including hippocampus, cerebral nuclei, cerebellum and 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. Hydroxyl radical scavenging has been shown in laboratory experiments. Whether that protects anything in a living person has not been tested.

4

Cholinergic enhancement (without direct receptor binding)

Pyritinol enhances acetylcholine release without directly interacting with cholinergic receptors. The proposed route involves membrane fluidity and lipid solubility rather than enzyme blockade. This comes from preclinical work and is a hypothesis for the trial findings, not an established pathway, and it is not a basis for comparing pyritinol with prescription dementia drugs.

5

Anti-inflammatory effects

Pyritinol has anti-inflammatory effects relevant to its prescription use in rheumatoid arthritis, proposed to act via SH-group effects on inflammatory mediators and neutrophil function modulation. In the one-task arthritis trial, ESR fell more with pyritinol than with auranofin (p=0.029). The mechanism itself remains proposed rather than established.

6

Plasma viscosity reduction and cerebral blood flow

Older pharmacology work reports reduced plasma viscosity and improved cerebral blood flow. Plasma viscosity was not measured in any study cited on this page, and nothing cited here supports use in vascular dementia or after a stroke.

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, Neuropsychobiology 26(1-2):65-70, doi:10.1159/000118898, PMID 1475039).

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 was statistically significantly superior to placebo on all three prespecified 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 activity, which the authors read as improved vigilance. This is the largest positive trial on the page, it dates from 1992, and it has not been replicated under modern standards. Pyritinol is not a racetam: it is a pyridoxine disulfide with no structural relationship to that class. The trial tested a prescription medicine in diagnosed dementia inpatients.

2
Pyritinol vs Auranofin in Rheumatoid Arthritis

Multicentre double-blind trial with an active comparator and no placebo group, European Multicentre Study Group (Lemmel EM 1993, Br J Rheumatol 32(5):375-382, doi:10.1093/rheumatology/32.5.375).

Adults with rheumatoid arthritis: 139 fully evaluable patients on pyritinol 600 mg/day and 142 on auranofin 6 mg/day (oral gold), treated for one year. No placebo group.

Response rate was 78% for pyritinol (61 of 78) against 59% for auranofin (58 of 98), p=0.009, with greater improvement in general well-being, ESR and hemoglobin. The harms belong in the same breath: adverse events occurred in 64% of pyritinol patients against 58% on auranofin, mainly skin and mucous membrane reactions (36%) and gastrointestinal complaints (30%), and 61 of 139 pyritinol patients (44%) dropped out within the year because of adverse events or lack of response. Single cases of proteinuria and of liver and blood abnormalities were recorded in both groups. This is a prescription drug trial in diagnosed autoimmune disease; it is not evidence for supplement use.

3
Pyritinol crossover trial in Alzheimer-type dementia (n=26)

Double-blind crossover trial (Knezevic S, Mubrin Z, Risberg J, Vucinic G, Spilich G, Gubarev N, Wannenmacher W 1989, Int Clin Psychopharmacol 4(1):25-38, PMID 2687355).

26 patients with clinical diagnosis of Senile Dementia of Alzheimer's type (SDAT). Randomly assigned to pyritinol or placebo in a double-blind crossover design; all had mild to moderate dementia. Assessments were psychiatric and neurological examination, psychometric testing, and regional cerebral blood flow at rest and during mental activation. There was no one-year follow-up phase.

Pyritinol was associated with significant improvement in cognitive performance, and blood flow measurements showed a normalized increase during mental activation. The paper reports no one-year follow-up, no 300 mg daily dose and no battery of seven memory tests; those details were listed here in error and belong to a different report. With 26 patients, a crossover design and a 1989 publication date, this is small, old and preliminary.

Side effects and drug interactions

Common Potential side effects

Not well tolerated at the doses studied. In the one-year rheumatoid arthritis trial, adverse events occurred in 64% of patients taking pyritinol 600 mg/day, and 61 of 139 (44%) dropped out because of adverse events or lack of response.
Mild GI upset (nausea, abdominal discomfort).
Skin and mucous membrane reactions (rash, itching, mouth involvement) were the commonest problem, affecting 36% of patients in the one-year trial. Pyritinol is not a racetam, so comparisons with that class do not apply.
Headache.
Serious reactions are documented, not theoretical. A BMJ case report describes severe cholestatic hepatitis induced by pyritinol (Maria 2004). A Gastroenterology report describes a 23-year-old man with three episodes of acute pancreatitis after taking pyritinol, in whom a controlled rechallenge with a single dose caused a fourth episode; the authors concluded that pyritinol has to be added to the list of drugs capable of inducing acute pancreatitis (Straumann 1998). Proteinuria, blood count abnormalities, taste disturbance and lupus-like reactions have also been reported. Yellowing of skin or eyes, dark urine, or severe upper abdominal pain means stop and seek medical care.
Pregnancy/lactation: avoid (insufficient data despite B6 origin).
Renal impairment: caution.
Long-term safety in healthy people is unknown. The longest controlled data runs one year, in rheumatoid arthritis patients under specialist monitoring.

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 disease-modifying antirheumatic drugs (gold, methotrexate): combining them is not standard practice and is a prescriber's decision, not a self-care one.
Anticoagulants: interaction data are limited. Alcohol and other substances that stress the liver: caution, since pyritinol itself has caused severe cholestatic hepatitis.
Interaction data overall are thin, and an absence of reports is not evidence of safety.
B6-related: monitor in patients with vitamin B6-related conditions.

Frequently asked questions about Pyritinol (Pyrithioxine / Encephabol)

What is pyritinol?

Pyritinol is a synthetic compound made of two vitamin B6 molecules joined together, sold online as a nootropic and licensed in some European countries as a prescription medicine for cognitive problems in dementia. It is not an approved US supplement or drug.

What is pyritinol used for?

The published trials were done in people with diagnosed dementia and in people with rheumatoid arthritis, at prescription doses under medical supervision. Use for mental energy or hangovers is not backed by any study cited here. The evidence is old, small and limited to patients.

How much pyritinol is used?

Trials used 600 mg per day, split into three doses, in patients under medical supervision. That is a prescription drug dose, not a supplement dose. Product quality and legal status vary, and self-dosing is not advisable.

Is pyritinol safe?

Side effects were common in the trial that counted them: 64% of patients had adverse events over one year and 44% stopped early. Severe cholestatic hepatitis and drug-induced acute pancreatitis have both been reported in case reports. 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); these are prescription doses under medical supervision, with no established dose for self-directed use. 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: Not well tolerated at the doses studied. In the one-year rheumatoid arthritis trial, adverse events occurred in 64% of patients taking pyritinol 600 mg/day, and 61 of 139 (44%) dropped out because of adverse events or lack of response. 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 Preliminary (1 out of 5). It is backed by 3 clinical trials and 5 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(5 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; 156 completers over 12 weeks, with significant improvement on the three prespecified cognitive and global measures. Honest framing: a single trial from 1992 in diagnosed dementia inpatients, cerebral metabolism was not measured, and there has been no modern replication.
  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. Honest framing: 26 patients, crossover design, published 1989, with no long-term follow-up, so it supports a short-term cognitive and blood flow signal only.
  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. It is also the main safety document on this page: adverse events in 64% of pyritinol patients and 44% dropping out within one year.
  4. Maria V, Albuquerque A, Loureiro A, Sousa A, Victorino R Severe cholestatic hepatitis induced by pyritinol BMJ. 2004;328(7439):572-4. doi:10.1136/bmj.328.7439.572.PubMedUsed to support: Case report of severe cholestatic hepatitis induced by pyritinol. Backs the rewritten safety section, which now leads with documented harm instead of reassurance, and backs the new liver caution in the interaction list. Honest framing: a single case report, and PubMed carries the title without an abstract, so nothing beyond severe pyritinol-induced cholestatic hepatitis should be claimed from it.
  5. Straumann A, Bauer M, Pichler WJ, Pirovino M Acute pancreatitis due to pyritinol: an immune-mediated phenomenon Gastroenterology. 1998;115(2):452-4. doi:10.1016/s0016-5085(98)70212-4.PubMedUsed to support: A 23-year-old man had three episodes of acute pancreatitis after taking pyritinol, and a controlled rechallenge with a single dose caused a fourth. Lymphocyte stimulation tests detected pyritinol-activated CD4 and CD8 lymphocytes, pointing to an immune-mediated reaction, and the authors concluded pyritinol has to be added to the list of drugs capable of inducing acute pancreatitis. Honest framing: one patient, but the positive rechallenge makes this unusually strong evidence of causation for a case report.