Coily Curls Need Careful Care. Bold, beautiful and naturally voluminous, coily curls are made up of thousands of z-shaped strands. Ouidad’s Coil Infusion™ formulas use monounsaturated oils and fatty acids capable of permeating the strand and infusing the hair with nourishment. Moisture glides on and through each strand, keeping 4a, 4b, and 4c curls healthy, luscious and defined.