Anyone else leave the hair salon with the blonde bombshell waves and dragon-sized confidence of Daenerys Targaryen, only to wake up a few weeks later to find your tresses more brass yellow than you'd like?

That's been my experience more times than I could count, and as a result I was getting my hair colored more times than I could afford. Then a new colorist told me about a purple (yes, purple!) color-neutralizing shampoo from Function of Beauty, a paraben, sulfate free and cruelty-free haircare brand with personalized blends for every hair type.

I asked my naturally blonde friends (lucky ducks) about it, and it turns out they've been using purple shampoo this whole time! Function of Beauty's version takes the purple experience to the next level: it's a fully customizable formula made just for your unique hair goals, so in addition to treating your brassiness, you can get heat protection, curl control, frizz ease, whatever your hair needs.

After just a few washes, it was easy to see why purple shampoo is all the rage. Whether I'm adding platinum highlights for summer or going for a natural ashy-blond look for winter, Function of Beauty's purple shampoo keeps my color looking fresher, and fights the brassy yellow creep for longer.

Here's everything you need to know about this amazing new formula.

What is purple shampoo?
Blonde is the only natural hair color that will fade with everyday exposure to the elements, but until now there wasn't a way to counter it without getting your hair re-treated.

Purple pigments in special made shampoos counteract brassiness or orangey tones for blondes in between salon visits. Why purple, you ask?

It's opposite yellow on a color wheel, which means when the just-right amounts are applied to your hair, the pigments naturally cancel out or neutralize unwanted brassy colors.

Why is it necessary?
The drier and more damaged our hair is, the more susceptible it is to turning brassy.

That's why us color-treated blondes are especially prone to brassiness over time—and, unfortunately, going to the salon more often to get rid of it only causes more damage and perpetuates the problem.

Purple shampoo and conditioner saves you time, money, and the health of your hair, all while making sure that your perfect shade shines.

How do I use it?
This depends on how you want your hair to look. If you're maintaining recent highlights, simply lather and leave the shampoo on your roots for 2-3 minutes before rinsing as often as you'd like.

Just like normal shampoo. If you're trying to make your hair more noticeably ashier in tone, let the shampoo sit for longer.

And if you're completely brassy, like I was when I first (thankfully!) found purple shampoo, lather the formula in your hair when it's dry and let sit for up to 10 minutes so it can penetrate your roots and really bring your hair back to life.

I'm not a natural blonde—is purple shampoo right for me?
That's the great thing about purple shampoo: it works for almost everyone! Whether your hair is natural or dyed blonde, bleached, platinum, or gray, chances are you can benefit from purple shampoo.

It even works wonders with lighter brunette shades like chestnut or caramel; if your highlights or ombré are looking a bit too orangey, purple shampoo will have a similar toning and neutralizing effect.

How do I get my purple shampoo?
Simply select the new "reduce brassiness" goal in the Function of Beauty hair quiz and you're all set!

Best of all, you still get to add four more hair goals to your personalized formula, because let's be real, we've got 99 hair goals and brassiness isn't one.

Another great feature of Function of Beauty's customization is that you can add deep conditioning as a hair goal -- this is especially awesome considering other purple shampoos can strip your hair of natural oils.

Function of Beauty has revolutionized customizable shampoo and conditioner, so your formula is custom made for your hair needs. Now, they're offering the perfect purple shampoo, so blondes don't have to compromise the customizable experience to treat their brassiness.

UPDATE: Function of Beauty is giving Topdust readers 20% off their first order. Follow this link and start the hair profile quiz!