The vitamin c I have has retinol too so I use it at night. Plus the niacinamide has done an amazing job of keeping my oiliness at bay during the day so I like using it in the AM.
Why do you use Niacinamide vs. Vitamin C in the morning? I've heard Vit C is best for daytime bc of it's antioxidant properties. Curious if you prefer niacinamide!