[Product question] Would using Cerave PM & The ordinary's niacinamide serum together be overkill?

Beauty Tips For Body Care
The serum comes in at 10% and last time I checked Cerave's PM lotion contained 4% i really wanted to try out the serum because of the price.. but would adding 2-4 drops into my lotion be too much?
Girls Blog 2015
Submitted by HO0T