Pyritinol
A vitamin B6-derived nootropic (two pyridoxine molecules bridged by a disulfide) marketed in some countries for cognitive impairment. It carries a notable risk of rare but serious hepatic and pancreatic reactions.
01 Overview
Pyritinol (pyrithioxine) is a semi-synthetic compound made of two pyridoxine (vitamin B6) units joined by a disulfide bridge. It has been marketed in Europe for dementia, cognitive impairment and, formerly, rheumatoid arthritis, and is used off-label as a nootropic and hangover remedy.
Its main safety concern is idiosyncratic but serious adverse reactions, including cholestatic hepatitis, acute pancreatitis and, historically, blood dyscrasias — reactions that led to restrictions in some markets.
02 Mechanism
Reported to improve cholinergic transmission and glucose uptake in the brain and to have antioxidant activity; the exact nootropic mechanism is not well defined.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common | 200–600 mg/day | Oral | Typically divided; higher clinical ranges used historically. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Cognitive support in dementiaOlder controlled trials suggested modest benefit in dementia. | Modest | Clinical | |
| Perceived reduction in mental fatigueReported by users; not established in healthy adults. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Hepatotoxicity and pancreatitisIdiosyncratic cholestatic hepatitis and acute pancreatitis have been reported. | Severe | Rare but serious | Clinical | |
| Skin reactions and blood dyscrasiasRashes and, rarely, blood cell abnormalities were reported historically. | Severe | Rare | Clinical |