Hello, i am a young adult 21years old. i wanted to know whether those various height increasing medicines really help?

Scams: At age 21, you have almost certainly reached your maximum height. The medicines are promoted by people who know they do not work, but that most people will not ask for their money back (they're embarrassed). You're male, though, and you can add lean muscle at the gym and look great regardless of height; you'll be admired for this and it trumps how tall you are. Good luck.