Do vitamins give instant stat increases or does the stat increase over time?

Question

I know all about EV training and how to stop raising EV of a stat once it adds up to 252.

But Im a little confused because I used ten proteins (100 EVs) on my larvitar lv5 and his attack didn't go up at all. i gave two lv5 larvitars one exp share each and their stats went up the same. The other one got no vitamins.

Are the changes visible later on in levels? - Or did i completely s***w up and waste 100,000 dollars?

Answer 1

EVs are distributed over the levels. If you did all the EV training at level 99, then the stats would of shot up by 63 or so points. At level 5, it has 95 levels to distribute 63 stats. Please note this is not taking IVs into consideration

Answer 2

For what game?