Hi,
hair loss for the most part is genetic. If your grandfather on your moms side is bald you're in for a rough ride. Mine is :(
my hair started receding when I was about 23. I think it was because of stress though.
I'm 27 btw and still got my hair...It receded a bit but I have it under control. I use this product called nioxin that really helps. It keeps the roots really clean and the hair strong. It stopped it from receding and hair is actually growing back.
There are a lot of products out there like this. A buddy of mine is using a different shampoo, I dont know the name, and it's helping him too.
Nioxin is expensive but the bottle lasts me 1 year. My hair is short and I wash it every 2 days. For about $100, you get shampoo, conditioner and this product to apply.
Cheers,