Performance/Hormonal/Cognition

Sulbutiamine

Synthetic thiamine derivative studied for chronic fatigue and erectile dysfunction, with limited but promising older clinical data in specific populations.

score

evidence

Caution

risk

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Use with caution

This supplement may interact with medications, medical conditions or sensitive populations. Review safety before use.

Overview

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Safety

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Quick Take

Niche option for chronic fatigue or psychogenic ED; evidence is small and dated, so most users should prioritize better-studied.

Sulbutiamine is a fat-soluble synthetic derivative of thiamine (vitamin B1) that crosses the blood-brain barrier more efficiently than standard thiamine. Used in some countries for functional asthenia, it increases central thiamine pyrophosphate and modulates glutamatergic and dopaminergic signaling. Small human studies suggest reduced fatigue, with very limited evidence for improved erectile function and memory. Best suited for those with persistent unexplained fatigue or psychogenic erectile dysfunction, though the evidence base is narrow and decades old.

Potential benefits

Reduces fatigue/asthenia

May improve erectile function

May support memory/attention

Protocol

Amount

200-600 mg

Frequency

Once daily, or split into two doses

When

Morning and early afternoon; avoid late-day dosing to prevent sleep disturbance.

Onset Time

1-3 weeks for fatigue benefits; acute alertness effects are possible but less.

Who Should Consider

Adults with chronic functional asthenia

Men with psychogenic erectile dysfunction

Patients with post-viral fatigue

Those seeking non-stimulant fatigue options

How It Works

Sulbutiamine crosses the blood-brain barrier and increases thiamine pyrophosphate in neural tissue, supporting central energy metabolism. Preclinical studies suggest modulation of glutamate and dopamine signaling, while small human trials indicate reduced somatic and psychic fatigue, possibly via enhanced cholinergic tone. Exact molecular targets in humans remain incompletely characterized.

Updated 5/19/2026