The phrase "buildable formula" refers to a product, typically in cosmetics or skincare, that can be applied or layered in multiple ways to achieve different levels of coverage or intensity. Full definition
A soft bristle brush and buildable formula leaves fringe with loads of volume and drama, but still with natural softness. (allure.com)
Buildable formula allows you to stick with a single layer of soft focused moisture, or layer up to create a poreless matte finish. (100percentpure.com)
Luxurious buildable formulas for all day, comfortable wear with adjustable coverage. (juicebeauty.com)