lol no ive heard all the chemicals f*** up your hair, no thx!
I'm a hair stylist and it's true that dyes and lightener can both damage your hair if you don't use them correctly, and you do have to up your hair-care system if you choose to use a permanent dye or choose to lighten it because of the process your hair has to go through for its color to be altered, but it doesn't fry your hair when used correctly :3
If you're curious, the components of permanent haircolor are ammonia, peroxide, and dye intermediates (the synthetic pigment that colors your hair). The ammonia opens up the cuticle (which is the clear layer of overlapping scales that protect your hair and make it look shiny). Once the cuticle is open, peroxide (which is in the developer) dissolves the natural pigment (melanin) in the cortex (the layer of hair below the cuticle where natural and permanent artificial pigment is housed). Then in the last 10 minutes of processing time the dye intermediates enter the hair, and begin forming color molecules in the cortex that are too big to escape back through the cuticle (which is why permanent dyes are permanent).
After using a permanent dye or lightener, it's a good idea to use a shampoo & conditioner especially for color-treated hair. The shampoo will bring your hair back to it's natural pH, and the conditioner will close the cuticle again, helping your hair to retain color, prevent fading, to feel soft and smooth again and to look shiny. If you don't, and your hair feels rough after you've colored it, or lacks shine, it's because the cuticle is still open (an open cuticle, by the way, means rough feeling, easily tangled hair that can't retain moisture, and eventually becomes dry and brittle).
Permanent dyes and lightener aren't the only option, however. If you don't want to make your hair any lighter, and want, instead, to go darker or just to add some color to your hair without going lighter or darker, semi-permanent and demi-permanent dyes are an option. Semi-permanent and demi-permanent dyes don't contain ammonia, so the cuticle stays closed and the natural melanin isn't altered in any way. Instead, color molecules are lodged between the scales of the cuticle and will dislodge over time and wash out when you shampoo. Over time, the color will fade out and your hair will return to it's natural color (assuming you haven't already permanently altered your hair color). Semi-permanent dyes last 4 to 6 shampoos and demi-permanent dyes last 4 to 6 weeks.
No matter what you decide to do, have a stylist do it for you. Color is SO easy to mess up, and sometimes when you lighten your hair after dying it, left-over dye molecules will re-oxidize, meaning that if you dyed your hair pink 6 months ago, let it fade out and you lighten it, the pink can reappear. Stylists know how to address issues like this, but the average person, does not.