GUILT-FREE GLAMOUR!® Shocking Blue AMPLIFIED is a dark cobalt blue hair dye. For best results, we recommend lightening hair to a very light cool-toned level 9 blonde or lighter. All semi-permanent blue hair colors can interact with yellow tones in bleached hair to create a green tint so make sure to do a strand test prior to applying all over to ensure you get the results you want! If you'd like to avoid a possible green undertone, you can add in a purple shade like Purple Haze to offset this effect. When mixed with Pastelizer, Shocking Blue becomes a gorgeous steely, blue-grey pastel shade!  Our Amplified Formula contains up to 30% more pigment than their classic counterparts! Also available in our Classic High Voltage Cream Formula! WEAR IT LOUD!® Details: Style: Amplified Semi-Permanent Hair Dye Color: Shocking Blue Color Description - Dark Blue Hair Dye Volume: 4oz / 118ml Ingredients: Vegan Friendly, PPD Free! Additional Features: Benefits of Conditioning Hair, Resealable Tub For Longer Use, Comes With Instructions, Longer Lasting Formula with 30% More Pigment Duration: up to 6-8 weeks with proper hair care  For Best Results: See Instructions Tab  Tested on celebrities, not animals™.