Do functional cosmetics really show results if applied consistently?

Things like whitening and wrinkles! As I get older, my skin tone becomes dull and fine lines appear around my eyes, so I’ve become very interested in functional cosmetics for whitening and wrinkle improvement. I make sure to apply them meticulously every day, but I suddenly wonder if using these expensive functional products so diligently actually produces noticeable results. When I look online or in advertisements, they claim your complexion brightens and wrinkles tighten after just a few weeks of use... haha. Honestly, since cosmetics aren't medicine, I worry that they might just sit on the surface of the skin without providing any fundamental improvement. Plus, there is a lot of exaggerated advertising. I’m really curious if it’s merely a preventative measure to keep things from getting worse, or if using them consistently for six months or over a year will actually make the skin clearer and more elastic enough for anyone to notice a difference.