SBT 把烟酰胺列为内层常用 INCI，与红没药醇、积雪草提取物、神经酰胺信号分子并列。

需要注意两点：一是浓度与耐受——烟酰胺应从较低频次起步；二是次序——它处于「活性物进入更深层」的阶段，应在保湿与脂质补充之后发挥作用。

换句话说，烟酰胺是加分项，不是地基。屏障尚未修护时先上高浓度烟酰胺，容易引发不适。

Two cautions: start at low frequency to build tolerance, and respect order — it acts after humectants and lipids have done their work.

Niacinamide is a bonus, not the foundation. High concentrations on an unrepaired barrier often cause discomfort.