HOW DO YOU USE THE ADVANCED BRIGHTENING KIT AND HOW LONG IS THE SHELF LIFE?Updated a year ago

Mix the entire vial of Hydroquinone as they are all equivalent to 2%. If you want 8%, you would need to add 4 bottles of Hydroquinone powder. If you add the Hydroquinone, it is good for 6 months after mixing. Without HQ, it is good for 9 months after mixing.