Pyritinol is a water-soluble, semi-natural drug which is derived from vitamin B6. It is also known as pyrithioxine or pyridoxine disulfide. Pyritinol was created in 1961 by Merck Laboratories, and is the result of joining two vitamin B6 compounds at their sulphur molecules. Their joining in this way is known as a disulphide bridge.
This drug has seen the most use in Europe, where several patented versions have been developed. In the early 1970s, pyritinol was sold as an over the counter (OTC) drug in many European nations. It was marketed as an aid for those with cognitive or memory function issues, and was also used to treat children with learning disorders.
There are several countries, including Great Britain, where pyritinol has not been licensed for use, but the drug is widely available over the Internet. In the United States, the Food and Drug Administration (FDA) has no official position on pyritinol, and the drug is relatively unknown in the rest of North America. Clinical tests conducted in the early part of the 1990s showed that participants who ingested pyritinol had an increased reaction time, but showed no improvement in memory function.
In the United States, the most common exposure to this drug has been as a dietary supplement, rather than an OTC drug. Pyritinol supplements fall in to a class of compounds known as nootropic, a term coined by a Romanian doctor in 1964. Nootropic compounds are said to increase mental functions, including cognition and memory. They are also known as smart drugs or memory enhancers. The term nootropic is a blend of two Greek words, and literally means mind-bending.
The action mechanism by which nootropic compounds operate is not fully understood, and the efficacy of such drugs has not been well documented. There are several schools of thought regarding how these compounds supposedly increase mental functioning, including theories that they increase the brain's oxygen supply, or that they change the availability of certain neurochemicals. Cognition, memory, and intelligence are not easy to quantify, making the job of empirically testing nootropic compounds difficult.
One of the main alleged benefits offered by pyritinol is an increased ability to deliver glucose to the brain. Unlike all other parts of the body, the brain can only function by utilizing glucose, and cannot rely on fat to produce energy. The brain is also unable to store glucose, and so must have a continuous supply. According to a study conducted in 1980, patients with brain glucose uptake levels at 50% of normal saw a significant increase when pyritinol was used. In a healthy individual, this increased glucose uptake would theoretically translate to increased energy, and more rapid brain function.