Subscribers’ Q&A: Using more than 5% niacinamide? Making a Pepha Tight formula?

In the May Q&A, Csoap asked: 1. I know Niacinamide isn’t recommended over 5-6%, but want about combining in application? I have 2 products I love that have 4% each. I sometimes use them together. I haven’t seen flushing but my skin turnover is amazing! But this combo can cause flushing, correct? If you use too…