Sulbutiamine is a synthetic, fat-soluble derivative of thiamine (vitamin B1), developed in Japan in the 1960s to treat beriberi. It crosses into the brain more easily than thiamine and is promoted for fatigue and focus.
Also known as: isobutyryl thiamine disulfide.
A small study in multiple sclerosis used 400 mg once a day for two months (Sevim 2017). These are study protocols, not a recommendation.
The NIH Dietary Supplement Label Database lists sulbutiamine products labeled as dietary supplements, such as BulkSupplements.com Sulbutiamine and Natural Factors BioCoenzymated Benfotiamine 150 mg plus Sulbutiamine. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling. Drugs@FDA lists no approved sulbutiamine product.
What studies show: evidence is very limited. In an uncontrolled study (no placebo group) of 26 people with multiple sclerosis, fatigue scores fell from 77 to 60.5 over two months; improvement was seen only in people also on disease-modifying treatment (13 of 23) and in none of the 5 who were not (Sevim 2017). A 2020 review said only a limited number of studies exist after 50 years and randomized trials are needed (Starling-Soares 2020).
Sports: the Moscow anti-doping laboratory found sulbutiamine in about 100 of roughly 16,000 urine samples in 2009, mostly collected in competition, and noted that one of its breakdown products looks similar to a breakdown product of the steroid boldenone in standard testing (Sobolevsky 2010).
Safety: no serious adverse events occurred in the multiple sclerosis study (Sevim 2017). The sources here do not describe drug interactions.
We could not find a single published half-life or time to peak for sulbutiamine that applies to a supplement dose, so we do not list one.
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