Please ask about yeast. 1. Yeast Resurface , Yeast Radiance™ and Galactomyces Ferment Filtrate (Pitera) is compatible. 2. Willow Bark Extract (Natural Salicylic Acid) can be combined. with Yeast Resurface or Yeast Radiance™ or Galactomyces Ferment Filtrate (Pitera) because you can see in the descrip...