Important!
One thing I think we should be careful about in regards to Sulbutiamine, is that since it's fat-soluble, there is probably a much lower tolerable intake threshold than normal Vitamin B1. The B vitamins are all water-soluble normally, as such it's extremely difficult to overdose on them, as the kidneys are capable of excreting excess fairly easily. However, since Sulbutiamine is fat-soluble it can build up in the body. This presents the issue of possibly causing chronic Hypertvitaminosis B1, which medical professionals might not be prepared to treat due to the fact that normally you could probably safely chug a bottle of Vitamin B1 pills and be perfectly fine (negative reactions have only been observed with high-dose intramuscular injections, never from oral intake).
As such, I'd limit daily doses to the brand manufacturer Arcalion's recommendation of 600 mg per day, if that doesn't produce effects, try calculating your therapeutic dose according to 12.5 mg/kg body weight (so 850 mg for a 68 kg/150 lb person).
Sulbutiamine raises thiamine concentrations in the brain however the raised thiamine is not becoming fat soluble, it stays water soluble therefore the risk is not that probable, there isn't information on the metabolization of sulbutiamine after it gives its effects, what I know is that effects start wearing off after few days of withdrawal so on a personal note I wouldn't say it is risky to take it.
What is risky is to take doses that are too large and would cause accumulation overtime, 1500mg with an half life of 5 hours would give you 58,59375mg of sulbutiamine after 24 hours, it is safe if you take this dose for 30 days then withdraw for 48 hours (less than 1mg would remain) and restart the cycle again.
With 600mg it is 23mg that accumulate each day, the difference overtime is not truly significant.
I never managed to have symptoms of vitamin B1 overdose from sulbutiamine however oral B1 consumed in large doses (1,5 grams) gave me palpitations, sweating and racing heart so it seems sulbutiamine isn't that dangerous as you say. If it was the case I would have already experienced these symptoms with my almost 2 month use.
But it's however true that effects accumulate overtime but that's just due to half life and not because it is fat soluble, fat soluble is here to keep higher plasma levels and have an higher half life, it doesn't eternally build up in the body, it does get excreted unless you prove the contrary.
Sulbutiamine has been available during several decades and a lot of people use it for asthenia everyday with no significant adverse effect, there was also a study to assess its clinical effects on Alzheimer patients, (here it's in french :http://www.neuromedia.ca/fr/sante/sulbutiamine.asp), to make it short early alzheimer stage patients took 600mg sulbutiamine a day during 3 months straight, though it doesn't talk about side effects the study was conducted to the end and seemed to be successful in boosting attention, episodic memory and executive memory.
3 months use of sulbutiamine at 600mg would cause a latent accumulation of 2109,375mg sulbutiamine which is quite high.
Also I'm interested by hypervitaminosis B1 due to IM injections, and also I have to say that hypervitaminosis B1 is poorly documented and seems to be almost inexistent.
The most important thing would be to respect half life excretion so that latent accumulation doesn't get to dangerous levels, using it straight for 30 days then withdraw during 2 days is a good compromise and seems to be the safest thing to do, however thanks for pointing that half life problem out as it wasn't really of my concern before.
Edited by renfr, 02 April 2013 - 08:49 PM.