If blonds have more fun and brunettes are smart and sophisticated, then pastel-haired ladies just might be the closest things to real-life unicorns. We kid—but only a little. If there’s one thing that makes colour-loving women swoon, it’s pastel hair.

Once a microtrend reserved for punks and ravers, cotton-candy strands are enjoying a resurgence and, dare we say, have spilled over into the mainstream. Top-tier celebrities such as Rachel McAdams, Kate Bosworth, Sienna Miller and Nicole Richie are embracing the style.

Are you ready to take the pink, peach or purple plunge? Still need some guidance? To get all the details on successfully going pastel, we chatted with Carolyn Mila, colourist at Medulla and Co., Toronto’s rainbow-hair colour authority. 

Placement is key

Beginner: If you’re fresh to the candy-colour hair game and looking to test the waters, Mila suggests dyeing a slice of hair. “Take a section on the inside part of the hair—not the top layer or under layer—somewhere in the middle.” This way, you won’t notice the colour until you pull your hair into a ponytail or move your hair around.

If you don’t have blond hair, you’ll need to lighten (bleach) the hair first and then apply your pigment. You can try hair dye or a more temporary product like hair chalk. We love L’Oréal Professionnel HairChalk and Kevin Murphy Color Bug.

Intermediate: Punch up your colour game by trying pastel ombré—graduated colour that’s darker at the roots through the midshafts, then gradually gets lighter from the midshafts to the ends.

Since this requires lightening the ends, you should be going to a salon, says Mila. Once the ombré effect is achieved, your colourist will deposit the pastel hue on the lifted hair.

Mila suggests trying smoky lavender hues. “Purples fade the best; they fade on-tone because purple counteracts brassiness.” That means you’ll be left with a brilliant blond once the purple washes out.

Expert: Go big or go home and try an all-over pastel shade. This will require you to lighten your hair—professionally—from root to tip. “Even lightening is the most important part of achieving pastel hair,” says Mila. “Once you have reached that blond, you can experiment with the pastel hues at home.”

Try mixing two parts conditioner with one part temporary colour from Manic Panic, a semipermanent dye that comes in rainbow of hues. Mila suggests leaving the mask on for five minutes, then rinsing it out.

The five best hues to try
Lavender: Smoky cool lavender looks good on all skin tones and fades beautifully; however, it's one of the hardest to achieve, says Mila.
Rose gold: A warm golden pinkish-peach is the best way to describe “rose gold” locks. This hue looks magical in the form of highlights or ombré hair.
Grey: Thought going grey was a hair nightmare? Think again. This is the most coveted kooky hair colour trend of 2015. It’s also tied with lavender as one of the most difficult shades to achieve.
Baby pink: An all-over powdery pink hue looks beautiful on all complexions; it also makes us reminisce about My Little Pony.
Teal: This saturated shade looks best on cropped hair with ombré placement. It plays nice with darker roots.

How to make it last
The most difficult part of soft candy floss shades isn’t achieving the colour, it’s keeping it around. “All pastel shades last only one to three washes; they’re high-maintenance,” says Mila.

Get comfortable with a good dry shampoo because you’ll need to abstain from washing your hair as much as possible. You can also replenish the colour with the conditioner-plus–Manic Panic hair mask.

Finally, Mila says to enjoy the ride as it fades out. “Some weeks it will look awesome, and others it will look a little strange, but then it will look awesome again.”

Read more:
Should you dye your hair red?
The lowdown on organic hair colour