SOBOOST are shades that can be mixed with the SoColor and ColorSync Collections to create soft pastel tones or applied full strength to pre-lightened hair for bold, vivid effects. All are intermixable for an endless variety of shade results.
Blue: Ideal for neutralizing unwanted brassiness and warmth when lifting hair; and for adding cool tones to dark hair.
Red: A go-to for intensifying red, red-violet and violet formulas.
Copper: Boost vibrancy in auburns, warm browns and golden blondes.
Yellow: An excellent solution for brightening brunettes and softening a too-strong red.
Check out the Matrix Hair Color Gallery