I'm starting to use a med called 'concerta' tmrrow. I've googled it and I've found that it's a side effect as stunting height growth. Is it true?

Temporary stunting. Concerta is a stimulant and it can reduce appetite - obviously if one is not eating enough as a child it impacts growth rate, but most studies show that growth delays return to normal once the medication is stopped or if the person getting the medication is properly nourished.