Review (5/5): Lasts forever on bleached hair!
This stuff is amazing. I don't know what they put in my hair at the salon, but even with only washing my hair in cold, and not every day, it still was fading almost immediately. I mixed just a little of this half and half with conditioner and left it on the pink part of my hair for half an hour, and it boosted the color right up! At first I did that every other week, but right now it's been a good 2 and a half months (and I gave up on cold washes a month ago - I visited Peru where it is winter, and wanted the hot showers!), and while the ends have faded a bit, most of my hair is still vibrant hot pink. I think when I get my roots done I'll just have them bleach it and put this on myself, since it seems to work and stay far better than what they used.
Also, there's plenty in this bottle! I only have about a third of my hair pink, but it's long and thick, and I've still only used less than a quarter of a bottle after 3-4 uses. It doesn't need to be full strength to work, in my experience, so I expect this bottle will last a good long time.
As with all fun color dyes, this will stain everything! Be careful, wear gloves, put vaseline around your hairline, put a shower cap or something on while you're letting it set, or you'll have pink where you don't want it!
Edit - it's now been over 10 months since I last touched up the color, and 10 months since I gave up taking special care of it. That's nine months of HOT showers, and not doing anything special, just plain shampoo and conditioner as I would usually do. There were parts at the ends that were lighter bright pink with hints of peachiness, but the majority was still a very bright hot pink! Not as dark as freshly dyed, but still very bright and vibrant. I had a ton of roots obviously, but the color was still fantastic. Last night I bleached my roots and re-dyed, and now my hair is even more super vibrant bright pink. I'm very pleased. I've finally got to the bottom of the bottle, so I'm re-ordering. Atomic Pink is my color. (Also, highly recommend Manic Panic's Dye Away wipes. They do a great job getting the stray dye spots off your ears and arms, and help a bit with surfaces too.)