Whats the most effective way to use the Vitamins?
If you’re desperate, use them as soon as possible, but if you want the full effect, do this. Remember that a Pokemon can take about 10 Vitamins before it work anymore on it. It seems that a Pokemon with a much higher Level, gains more stat points if you use a Vitamin on it. For example, a Pokemon at L10 will only gain 1 stat point for each Vitamin used which would mean it would gain 10 points for 10 Vitamins. But if you use one on a L100 Pokemon, it would gain a whopping 40 stat points! So my point here is this, use the Vitamins on a Pokemon when you have trained as far as you can.