Vitamin B1 is referred to as thiamine as CFC mentioned above. Its apart of the B complex and is a major factor in metabolic efficiency. I think the RDA was like 1mg or something extremely miniscule. Basically if you somehow manage to achieve thiamine deficiency without having compounding medical issues exacerbating the possibility of malnutrition or missing specific intrinsic factors that are associated with successful absorption then you need to learn how to eat again or you really need to lay off the shellfish.
Now to confuse myself. There is quite a few thiamine derivatives, thiamine vitamers and even thiaminase (an ezyme that breaks down the thiamine molecule) Some types of thiamine derivatives have no physiological significance to preventing deficiency, but are catalysts in other metabolic equations. Its honestly pretty confusing to me and I've never taken the effort to make sure I get adequate intake of thiamine or to try to understand the complex system that its involved in. Some forms of thiamine such as AThDP (Adenosine thiamine diphosphate) are not even fully understood and have no perceived significance at this moment. They just know it exists.
Just to add to another layer of confusion. Thiamine as itself is actually a vessel for other naturally occurring thiamine derivatives.
Every cell in our body responds to thiamine and with that being said thiamine deficiency is felt at all physiological levels. It tends to be more pronounced at the neurological level because its a major factor in oxidative metabolism. You can fall into a coma if the deficiency was allowed to fester for long enough and subsequently lead to death. Now I don't know about you, but I'm not too fond of dying anytime soon.
Had to look up what Benfotiamine was. Here is the fancy name...
S-benzoylthiamine O-monophosphate which is a synthetic S-acyl derivative of your good friend, thiamine. Just for some background information, S-acylation is the chemical process of linking two molecules together with a thioester bond. A thioester is the result of esterification of carboxylic acid and thiol. What does this mean? I really don't know, but if you are willing to dive further than me than here is a great link.
https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/pentose.htm
The alleviation of the sciatica is achieved by utilizing the Pentose Phosphate pathway.
Being utilized as a pre-workout supplement. I'm not 100% following. Are you trying to prevent any aggravation to the nerve? A preventative measure to help alleviate oxidative stress? I don't know of any vitamin belonging to the B complex being an absolute make or break in reference to pre-workout supplementation. I guess if you were really interested in experimenting you could megadose pantothenic acid (Vitamin B5) it helps promote the breakdown of lipids which could give you an incredibly unrecognizable net increase in lipolysis.
Cobalamin with its respective molecules (cyno,methyl,adenosyl) could cause a temporarily spike in body temperature if administered via I.M within 30 minutes before exercising. It produces very mild thermogenic activities, but B12 aids in metabolic regulation. I guess if you wanted to be very technical I could see B6 being an ingredient in pre-workout supplements. This is because its actually pretty difficult to identify any process in the body that doesn't utilize B6. B6 also plays a major role in how effective your body utilizes carbohydrates for energy.
I mean the whole vitamin B Complex has been associated as the energy vitamins and that statement does have some truth to it. Would missing out on B Complex supplementation be overwhelmingly detrimental to a successful workout? Nope.
