We have not tested Kirei in correlation with other products, however, we have so many customers who create their own personalized skin care routine with their existing products combined with Kirei. It is all about creating the perfect customized skin care routine that works best for your skin type and that is what is so fun about skin care.
If you choose to incorporate other products into your routine, we suggest doing so after using step one. This way your remaining steps can still work together with the way they were designed to!
Please email our skincare experts at firstname.lastname@example.org! They will be happy to answer any questions you might have!