TTFD / Allithiamine (fat-soluble B1)
What it is
Thiamine tetrahydrofurfuryl disulfide (TTFD) is a fat-soluble thiamine derivative that readily crosses the blood-brain barrier and cell membranes, achieving intracellular concentrations far exceeding water-soluble thiamine HCl at equivalent doses. Synthesised in Japan for thiamine-dependent conditions, it is used in functional medicine for dysautonomia, POTS, chronic fatigue, Wernicke's encephalopathy, and conditions where standard thiamine fails to normalise function. Small case series and clinical observations show improvements in fatigue and autonomic symptoms. Evidence base relies heavily on case reports and small open-label studies — robust RCTs are lacking.
Dose
25–100 mg/day TTFD; start at 25 mg and titrate slowly; some neurological protocols use 100–300 mg/day under supervision
Time of day & tips
Take with food — sulphur-containing compound that can cause body odour (reduce dose if problematic). Start low and increase slowly. Allithiamine is the garlic-derived precursor with similar fat-soluble properties. Work with a knowledgeable practitioner for neurological applications. Monitor for paradoxical worsening at high doses in some individuals.
Cycling
Usually taken continuously for neurological support. Response assessment typically at 4–8 weeks. No established cycling evidence.
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