Prosultiamine (Alinamin, Binova, Jubedel, Taketron, Thiobeta, Thiotiamina), also known as thiamine propyl disulfide (TPD), is a disulfide thiamine derivative developed in Japan in the 1950s as a treatment for vitamin B1 deficiency. It has improved lipid solubility relative to thiamine and is not rate-limited by dependency on intestinal transporters for absorption, hence the reasoning for its development. It is also a potential treatment for HTLV, since it has been shown to reduce viral load and symptoms.