I want to use this after my retinol at night, but i‘m not sure if the niacinamide percentage is high enough. I wanted a 3-5% concentration, would it be possible to integrate an extra niacinamide serum of that percentage if it‘s too low in this product?
The concentration of niacinamide in this product is most likely below 3% (I'd guess it closer to 1%, but we don't know for sure), so it won't hit your goal of 3-5%, I'd add a niacinamide before it going for something with a moderate concentration - something like this one https://whatsinmyjar.com/product/vichy-mineral89-defence-serum-4-niacinamide