Your body needs vitamins in order to form complex aminos to operate. But your body only needs to make so many of them - especially if you are an adult, not pregnant, or not suffering from a disease of some sort.
The very premise that loading up your body with "excess" vitamins beyond what you need is already pretty fraught. Building a house without enough lumber can lead to long term deficiency - but loading up a construction site with more materials than are needed shouldn't automatically be assumed to be good.
The reality is that the modern diet has already solved so many common nutrient deficiency diseases (pellagra and goiters were a shockingly common diseases 100 years ago) that maxing out on vitamin intake has become more of something like a speculative hobby than anything else.
The very premise that loading up your body with "excess" vitamins beyond what you need is already pretty fraught. Building a house without enough lumber can lead to long term deficiency - but loading up a construction site with more materials than are needed shouldn't automatically be assumed to be good.
The reality is that the modern diet has already solved so many common nutrient deficiency diseases (pellagra and goiters were a shockingly common diseases 100 years ago) that maxing out on vitamin intake has become more of something like a speculative hobby than anything else.