Limited evidenceBrain & cognition

Sulbutiamine

A lipophilic thiamine derivative that crosses into the brain more readily than thiamine. Marketed for fatigue and focus on the strength of a handful of small, mostly uncontrolled studies.

Evidence last reviewed: August 2026

What the science says

Fatigue Limited evidence
An open study in patients with multiple sclerosis reported reduced fatigue scores with sulbutiamine, and older trials in post-traumatic asthenia described similar improvements. None was placebo-controlled with an adequate sample, and no trial has tested it for everyday tiredness in healthy adults.
Cognition in Alzheimer's disease as an add-on Limited evidence
A multicentre randomized trial combining sulbutiamine with an acetylcholinesterase inhibitor in early to moderate Alzheimer's disease reported an effect on episodic memory and attention subscores but not on the primary global measure. The finding has not been replicated.
Nootropic use in healthy people Limited evidence
A review of sulbutiamine notes that its pro-cognitive reputation rests largely on rodent object-recognition work and on small clinical series in asthenia; there is no controlled trial of memory or focus in healthy adults.

Dosage & safety

Studied doseClinical use has been 400–600 mg/day, usually in two divided doses taken in the morning. Cycles of a few weeks are typical because tolerance is commonly reported anecdotally.

SafetyReported effects include headache, nausea, insomnia and, less often, agitation or mood elevation; case reports describe misuse and dependence at high doses. It is a prescription drug in some countries and is not approved as a supplement everywhere. Avoid in bipolar disorder, and in pregnancy and breastfeeding, where data are absent. It does not substitute for treating an underlying cause of fatigue.

Scientific references

Role of the Synthetic B1 Vitamin Sulbutiamine on Health
Starling-Soares B, Carrera-Bastos P, Bettendorff L — J Nutr Metab, 2020
Sulbutiamine shows promising results in reducing fatigue in patients with multiple sclerosis
Sevim S, Kaleağası H, Taşdelen B — Mult Scler Relat Disord, 2017
[Effects of the association of sulbutiamine with an acetylcholinesterase inhibitor in early stage and moderate Alzheimer disease]
Ollat H, Laurent B, Bakchine S — Encephale, 2007

Where to buy

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