I am still 25 years old (going 26 this June), but I have already started using peps this year. So, technically, I started using peps at the age of 25 1/2 years old. I might have started earlier than 30, but still, I can't recommend it to you. Why? You are still in your early 20s. It seems like you have just gotten out of being a teen. Just wait until your mid or late 30s and you can already do the pep shots.
peptides at the age of 21? Dear, you are clearly going to ruin your natural gh output. That means that you won't get a lot from using it anyway aside from shedding too much money. Think twice.
Mate, you better wait until you are 30. I was 27 years old when I first got interested with peptides. However, due to the recommendations of other users, I decided to wait until I turn 30. I just turned 30 years old two days ago and I am very happy to tell you that my peptides are already on their way. I did not regret waiting for three years. After all, I am sure that I will get the best out of it as I have followed the recommended starting age of using peptides.