Fursultiamine also known as thiamine tetrahydrofurfuryl disulfide (TTFD), is a disulfide

Disulfide

In chemistry, a disulfide usually refers to the structural unit composed of a linked pair of sulfur atoms. Disulfide usually refer to a chemical compound that contains a disulfide bond, such as diphenyl disulfide, C6H5S-SC6H5....

 derivative of thiamine, or an allithiamine

Allithiamine

Allithiamine , or thiamine allyl disulfide , is a lipid-soluble form of vitamin B1 which occurs naturally in garlic. It is more bioavailable than the water-soluble form of vitamin B1, thiamine, and is the preferred form to be taken in case of a vitamin deficiency....

. It was synthesized in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 in the 1960s for the purpose of developing forms of thiamine with improved lipophilicity for treating vitamin B₁ deficiency (i.e., beriberi

Beriberi

Beriberi is a nervous system ailment caused by a thiamine deficiency in the diet. Thiamine is involved in the breakdown of energy molecules such as glucose and is also found on the membranes of neurons...

), and was subsequently commercialized not only in Japan but also in Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, and the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. As a vitamin

Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...

, it is available over-the-counter as well.

In addition to to its clinical indication of avitaminosis

Avitaminosis

Avitaminosis is any disease caused by chronic or long-term vitamin deficiency or caused by a defect in metabolic conversion, such as tryptophan to niacin...

, fursultiamine has been studied in clinical trial

Clinical trial

Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...

s for Alzheimer's disease

Alzheimer's disease

Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

 and autistic spectrum disorders with positive but modest benefits. It has also been investigated in improving energy metabolism during exercise and reducing exercise-induced fatigue with conflicting results.