By taking a multi, you wont notice anything in the gym. Taking a multi has nothing to do with athletic performance (in any area) what so ever. Taking a multi will not make you faster, give you more strength, make you bigger, etc etc.
A multi vitamin is to supply you with nutrients for metabolic processes in the body, and the reason we take them is to get an adequate amount. Most of us take in a hair more just because we are very active. BUT at the same time too, we probably eat better than the average person, so we really dont need that much contrary to belief. You will have people take 1,000s of a % of something higher than they need ALL the time, and of lots of them, and for reasons unknown. A good multi as in one a day is fine.
In fact new research is coming out about how the more people take, the more problems they actually have. Some still sway the other way. There is no DEFINITIVE answer quite yet, but if an RDA is 100% of a nutrient, and you take 200-300% you should be just fine. People say... What does the FDA know about RDA? Again, it is 100%, and we take into consideration being very active, so we up it.
And to restore...what you are pissing out are your water soluble vitamins your body is not using. This is why it is of no use to over-do them. Your body is NOT utilizing them, and they are being excreted. So yes, part of the neon yellow is an excess of b-vitamins.
Throttle... B-vit do contribute to energy metabolically. But again, they contribute, not provide. And as far as diminishing, the only way to really get a benefit from them for that particular reason is INJECTION only as there is no other way for them (like B12) to be effective.