Seriously what will happen if I use this "Light Reddish Blonde" on my medium golden brown

excellence 9RB light reddish blonde..... starting color... medium golden brown (but dyed, was light blonde before)

Can I at least get a nice lighter slightly reddish color?

will it lighten much at all or should I blonde it first? I want it lighter. its a 9!! thats one of teh highest numbers so i thought itd do the trick id be happy with DARK reddish blonde................ doesnt have to be super light like box,

Seriously what will happen if I use this "Light Reddish Blonde" on my medium golden brown hair?????

It will turn red... and sometimes orange.

Seriously what will happen if I use this "Light Reddish Blonde" on my medium golden brown hair?????

Yes it will lighten for you but it could go orange too. Because of the brown in your hair. You could always try a beauty school to change your color. They are cheap and will be able to get the right color the first time and then you could use what you bought the next time to keep it up.