Agree with woriedd. The only two topical ingredients scientifically proven to have an effect on the visible signs of skin ageing are retinol (a vitamin A derivative) and broad spectrum SPF (UVA & UVB protectant).
You can buy all kinds of retinol products but so e are quite irritating. I’ve been experimenting with skincare for years and so my skin is fairly tolerant but even I have had issues with a lot of the high street stuff.
Eyes and lips are the first to ‘go’ because the skin is very thin and often doesn’t get sun protection.
I am currently using the Medik8 Crystal Retinal 6 serum, which is a sort of retinol but one that has been tinkered with to be incredibly effective but also incredibly gentle on skin (to do with the the number of conversions retinols have to do on the skin beforehand they become useable for the cells - more conversions = more irritation). It is expensive though, £59 for 30ml. It also has a stated amount of active ingredient.
You can get other retinol products for a lot less money but you might not like the texture (Ordinary, I’m Looking at you) or they might be irritating (La Roche Posay Redermic R, you). Also, be aware that lots of products say that they have retinol (or any ‘special’ ingredient) but don’t state how much, so chances are, you are putting minuscule amounts of active ingredient on your face and consequently are unlikely to see any difference.
You can also get retinol products on prescription (tretinoin is the biggie) but they are harsh on skin, peeling and whatnot. Usually only available through private prescription. I know some people buy from dodgy overseas websites but I wouldn’t advocate buying prescription drugs from unknown, unregulated sources.
You do need to use some form of good quality SPF that gives UVA & UVB protection every day, 365 a year. UV light is the biggest skin ager.