Sulbutiamine
Summary
Sulbutiamine is a synthetic vitamin B1 derivative licensed in France for apathy-type states. Its largest placebo-controlled trial, in 326 people with post-infection fatigue, found no overall benefit, and other studies are small or uncontrolled. The FDA says it is not a dietary ingredient, and it is on the US military's prohibited supplement ingredient list.
Key facts
- In a 2025 warning letter the FDA said sulbutiamine is not a dietary ingredient, so declaring it as one misbrands a supplement; the letter did not decide whether it could be used lawfully in other ways. It is not approved as a drug in the US and is on the DoD Prohibited Dietary Supplement Ingredients list.[2][3]
- Arcalion 200 mg: adults only, 2–3 tablets a day (400–600 mg) split between breakfast and lunch, for no more than 4 weeks; not for children or adolescents.[1]
- In 326 general-practice patients with post-infection fatigue, 400 or 600 mg/day for 28 days did not beat placebo overall; a day-7 benefit in women on 600 mg did not last.[4]
- About 100 of roughly 16,000 doping-control urine samples analysed in Moscow in 2009 contained sulbutiamine, mostly collected in competition; one metabolite runs very close to a boldenone steroid metabolite on screening.[11]
- A case report describes a person with bipolar disorder who used ever-increasing amounts, which disrupted psychiatric care.[12]
- 4 graded human outcomes on this page
- October 13, 2026
How it works
ProposedSulbutiamine is a lipophilic disulfide that the body converts to thiamine: after injection, thiamine in plasma behaves exactly like ordinary thiamine, and intact sulbutiamine has never been identified in animal brain after oral or injected dosing. It crosses into the brain more readily than thiamine and raises brain thiamine and thiamine phosphate levels, and animal work suggests effects on cholinergic and glutamatergic transmission. Whether this changes fatigue or memory in people is unproven.[13][8][6]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Fatigue | Grade D | Improved | Observational · n = 1,772 · 2003 | 3 rows |
| Nerve function | Grade D | Mixed | Open-label · n = 30 · 2002 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Weakness and fatigue during infection (added to anti-infective drugs) | Improved | Grade D | Observational · n = 1,772 · 2003 Patients with infections and weakness symptoms seen by 350 physicians (India) Form: Sulbutiamine · Dose: Not stated in the abstract · Duration: 15 days 51.7% reported complete resolution of weakness symptoms; side effects were reported in 0.6%. | 14710977 (opens PubMed)Source [9] |
| Nerve conduction in type 2 diabetic polyneuropathy | Mixed | Grade D | Open-label trial · n = 30 · 2002 Adults with type 2 diabetes and polyneuropathy (Malaysia) Form: Sulbutiamine · Dose: 400 mg/day (dose per a 2020 review) · Duration: 6 weeks Median and peroneal nerve conduction velocity and muscle action potentials improved vs no treatment, but symptom and sign scores did not differ between groups; glucose control was unchanged. | 22969314 (opens PubMed)Source [7] |
| Fatigue in multiple sclerosis | Improved | Grade D | Open-label trial · n = 26 · 2017 Adults with multiple sclerosis and prominent fatigue (Turkey) Form: Sulbutiamine · Dose: 400 mg/day · Duration: 2 months Fatigue Impact Scale total fell from 77 to 60.5 (P < 0.01) with no serious adverse events; clear improvement was seen in 13 of 23 people also on disease-modifying drugs and in none of the 5 who were not. | 28755683 (opens PubMed)Source [8] |
| Chronic post-infection fatigue | No effect | No effect | RCT · n = 326 · 1999 General-practice patients with chronic post-infectious fatigue (France) Form: Sulbutiamine · Dose: 400 or 600 mg/day · Duration: 28 days No overall difference from placebo on a validated multidimensional fatigue scale or other measures; women on 600 mg had less fatigue on day 7 only, with no effect at day 28. 315 of 326 completed. | 10573727 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Sulbutiamine tablets or capsules | Varies[1][13] | French label: rapidly absorbed, with peak blood levels 1–2 hours after an oral dose, a half-life of about 5 hours and urinary elimination. It is converted to thiamine in the body; intact sulbutiamine has never been identified in animal brain after dosing.[1][13] | French label: agitation, headache, tremor, nausea, vomiting, rash and malaise are uncommon; stomach pain and diarrhoea occur at unknown frequency. Overdose causes transient agitation with euphoria and tremor.[1] | Post-infection fatigue, MS fatigue, inhibition during depression, Alzheimer's add-on therapy, diabetic neuropathy and childhood bedwetting |
Studied doses
Doses studied in human trials ranged from 100 mg/day (children with bedwetting, 6 months) to 400–600 mg/day in adults for 4–8 weeks. The French Arcalion label allows 400–600 mg a day in adults for no more than 4 weeks and excludes children and adolescents.[10][4][5][1]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Who should be careful
- Children and adolescents
- The French label says safety and efficacy are not established and it must not be used in this group.[1]
- Pregnancy and breastfeeding
- French label: better avoided in pregnancy as a precaution, and must not be used while breastfeeding.[1]
- US service members
- Sulbutiamine is on the DoD Prohibited Dietary Supplement Ingredients list.[3]
- Tested athletes
- Doping-control labs detect sulbutiamine in urine, and one metabolite appears very close to a boldenone (anabolic steroid) metabolite in steroid screening.[11]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Frequently asked questions
Is sulbutiamine legal in US supplements?
The FDA said in a 2025 warning letter that sulbutiamine is not a dietary ingredient, so a supplement that declares it as one is misbranded; the letter left open whether it could be used lawfully as a non-dietary ingredient. It is not an approved US drug, and the Department of Defense lists it as a prohibited supplement ingredient.[2][3]
Does sulbutiamine boost energy?
Not convincingly. Its largest placebo-controlled trial (326 people with post-infection fatigue) found no overall benefit. Positive reports come from an uncontrolled MS study of 26 people and an uncontrolled commercial study during infections.[4][8][9]
How is sulbutiamine different from thiamine?
It is isobutyryl thiamine disulfide, a fat-soluble form that is converted to thiamine in the body and reaches the brain more readily than thiamine. In France it is sold as a medicine (Arcalion), and the US FDA does not consider it a dietary ingredient.[4][13][8][1][2]
Can athletes use sulbutiamine?
Anti-doping labs detect it: about 100 of roughly 16,000 samples tested in Moscow in 2009 contained it, mostly in competition, and one metabolite can interfere with steroid screening.[11]
What else has sulbutiamine been tested for?
In depression it showed no antidepressant effect but less psycho-behavioural inhibition (600 mg/day, 8 weeks). A small Alzheimer's trial added it to donepezil. In 450 children with bedwetting, 100 mg/day gave more complete responses than imipramine (52.7% vs 37.3%) in a single trial with no placebo group; the French label still excludes children.[5][6][10][1]
Sources
- [1]ARCALION 200 mg, comprimé enrobé: Résumé des Caractéristiques du Produit. ANSM, Base de données publique des médicaments (updated 16 June 2021), 2021. label
- [2]Warning Letter: Gluten Free Remedies LLC, MARCS-CMS 687832 (Sulbutiamine Plus Brain Support). US Food and Drug Administration, 2025. safety-communication
- [3]Sulbutiamine in Dietary Supplements. Operation Supplement Safety (US Department of Defense), 2023. fact-sheet
- [4][Treatment of chronic postinfectious fatigue: randomized double-blind study of two doses of sulbutiamine (400-600 mg/day) versus placebo].. Rev Med Interne, 1999. RCT
- [5][Effects of sulbutiamine (Arcalion 200) on psycho-behavioral inhibition in major depressive episodes].. Encephale, 2000. RCT
- [6][Effects of the association of sulbutiamine with an acetylcholinesterase inhibitor in early stage and moderate Alzheimer disease].. Encephale, 2007. RCT
- [7]Effects of sulbutiamine on diabetic polyneuropathy: an open randomised controlled study in type 2 diabetics.. Malays J Med Sci, 2002. open-label
- [8]Sulbutiamine shows promising results in reducing fatigue in patients with multiple sclerosis.. Mult Scler Relat Disord, 2017. open-label
- [9]Adjuvant role of vitamin B analogue (sulbutiamine) with anti-infective treatment in infection associated asthenia.. J Assoc Physicians India, 2003. observational
- [10]Comparative evaluation of sulbutiamine and imipramine in the treatment of primary nocturnal enuresis: A randomized controlled clinical study.. J Pediatr Urol, 2026. RCT
- [11]Sulbutiamine in sports.. Drug Test Anal, 2010. observational
- [12]Sulbutiamine, an 'innocent' over the counter drug, interferes with therapeutic outcome of bipolar disorder.. World J Biol Psychiatry, 2006. observational
- [13]Role of the Synthetic B1 Vitamin Sulbutiamine on Health.. J Nutr Metab, 2020. review
What changed
- Initial editorial evidence review: every PMID checked against NCBI esummary (title, year, no retraction or expression-of-concern flag); doses, sample sizes and durations re-read against the PubMed abstract or open full text; grades kept conservative; interactions limited to what a cited source supports.
- Adversarial review: corrected the pharmacokinetic wording to what the 2020 review supports (never identified intact in animal brain), added the FDA warning letter's footnote nuance, quantified the MS subgroup result, and qualified the paediatric bedwetting trial.