Is there anywhere on the net where I can find out the ingredients used by a specific skincare product?

Also, any source to validate if the product leaflets are telling the truth about the ingredients they used?

You want to go to the Environmental Working Group. About a year ago I became obsessed with reading this website. It’s a non profit consumer watchdog kind of site. They have a specific site for cosmetics. Here is the link. Wow, its really interesting, however you’re going to find out a lot of stuff you didn’t want to know about what you’re putting on your skin.