Fursultiamine is a derivative of thiamine (vitamin B1) designed to improve bioavailability and tissue penetration compared to standard thiamine. The use of thiamine and its derivatives to support or treat peripheral neuropathy has a scientific basis, particularly in the context of neuropathy associated with thiamine deficiency (such as in chronic alcoholism or malnutrition). Several clinical studies, mostly from Japan where fursultiamine is commonly used, have shown that high-bioavailability thiamine derivatives (including fursultiamine and benfotiamine) can improve neuropathic symptoms, such as numbness, tingling, and pain, especially in diabetic and alcoholic neuropathy.

However, the quality and scale of these studies are moderate, with some randomized controlled trials and observational studies indicating benefit, but larger, high-quality trials are still needed. Most of the data support efficacy for neuropathies where thiamine deficiency is a contributing factor; evidence is less robust for other types of neuropathy. International guidelines sometimes mention thiamine derivatives as supportive therapy, but they are not considered first-line treatments for peripheral neuropathy of all causes. Overall, there is moderate scientific validation for the use of fursultiamine in certain neuropathies, justifying a mid-range evidence score.