is this product cruelty-free?

Yes! A+ (and all Sunday Riley products) are certified cruelty free by both PETA and Leaping Bunny

What percent retinol is this? Using drunk elephants 1% retinol cream so curious which is stronger

It is a 6.5% solution of stabilized retinoid blends and botanical retinol-alternative extracts.

what skin products you should not mix with this?? some people say do not use any vitamin c whit this so i'm a little confuse

A+ can be used with Vitamin C, how often really comes down to what your skin enjoys and can tolerate. We encourage anyone who wants to try our high-dose retinoid A+ serum to start slow. Before you start mixing it with other actives we recommend using A+ along with a hydrating moisturizer 2-3 nights a week. After a few weeks of using this way, you can then up your usage to every other evening and continue using it this way for another few weeks. Feel free to email us at hello@sundayriley.com and one of our skincare experts can work with you to create a personalized routine!