How to Use Kérastase Genesis Serum (NZ Stylist Guide)

Updated October 2026. Prices are our live online prices.

The Genesis serum is the product people buy, use for ten days, and give up on. Then they tell us it didn't work. Nearly every time, the problem is how they used it: on the lengths instead of the scalp, three times a week instead of daily, or stopped well before six weeks.

Here's how we tell clients to use it, and how to fit it in with the rest of the Genesis range.

What is the Genesis serum for?

It's a leave-in scalp treatment for hair that's falling because it's weakened and breaking. You notice that as more hair in the shower drain, the brush and on your pillow than there used to be. It's made with ginger root and edelweiss to strengthen the hair from the root.

Being straight about the limits, because they matter: Genesis is haircare, not medicine. It won't regrow a receding hairline or treat pattern hair loss. Sudden shedding after having a baby, illness or a stressful few months is usually temporary (see our postpartum hair guide), and if you're losing hair in patches or it keeps going, see your GP.

How to use Kérastase Genesis serum, step by step

1. Start with a dry or towel-dried scalp. Clean is best, but it doesn't need to be freshly washed.
2. Section your hair. Make a parting down the middle, then two or three more on each side.
3. Apply it along the partings, directly onto the skin, not on the hair. Concentrate on where you notice the most thinning, usually the crown and hairline.
4. Massage for a minute with your fingertips, not your nails. This spreads it and gets the scalp's circulation going.
5. Don't rinse. Style as normal. It's light enough not to make roots greasy.

Morning or night? Either. Most of our clients do it at night, because it's part of a routine they won't skip and there's no styling to worry about afterwards. If you're also using the 8H Magic Night Serum, the Genesis serum goes on the scalp and the night serum on the lengths.

How long does it take to work?

Give it six weeks of daily use. That's how Kérastase designed it, and it matches what we see. The first thing people notice is usually less hair in the brush and the drain, at around the four- to six-week mark. Hair that feels stronger and snaps less when you style it comes after that.

Take a photo of your parting and your brush on day one. Day to day you won't see it, and the comparison is the only honest way to tell.

The full Genesis routine, in order

The serum does the most work, but the shampoo and conditioner matter more than people think. Weak hair breaks most during wet detangling, so a conditioner that lets a comb glide through, like the Fondant Renforçateur, saves hair every wash. Pick your shampoo by your scalp: Hydra-Fortifiant if it gets oily or your hair is fine, Nutri-Fortifiant if it's dry.

For a present, the Genesis Christmas Gift Set ($199.00) has the full-size Bain Hydra-Fortifiant, Fondant Renforçateur and Défense Thermique in a gift box. It doesn't include the serum, so add one if they're worried about shedding.

Genesis serum for men

Men's hair fall looks different, often at the crown and temples, and the Genesis Homme serum is the version for it. It's used the same way, daily on the scalp. Pair it with the Genesis Homme thickening shampoo. The same honest caveat applies: if it's a receding hairline, that's genetic and it's a GP conversation.

Genesis or Densifique?

If not much is falling out but your hair has gone finer and flatter over the years, that's a density problem, and Densifique is the range for it. Plenty of people have a bit of both. In that case, use the Genesis serum on your scalp and wash with Densifique. Our Genesis vs Densifique guide goes through how to tell which you have.

Kérastase Genesis serum questions

How do you use Kérastase Genesis serum?

Apply it to a dry or towel-dried scalp, section by section along your partings, massage in with your fingertips and don't rinse. Use it once a day for at least six weeks.

Do you put Genesis serum on wet or dry hair?

On a dry or towel-dried scalp. Apply it to the skin along your partings, not to the lengths of your hair.

Should I use Genesis serum in the morning or at night?

Either works. Many people use it at night because it's easier to stick to and there's no styling afterwards. The important part is using it every day.

How long does Kérastase Genesis serum take to work?

Use it daily for six weeks. Most people first notice less hair in the brush and shower around the four- to six-week mark.

Does Kérastase Genesis serum regrow hair?

No. It's a haircare product for hair that falls because it's weakened and breaking. It doesn't treat genetic or pattern hair loss, which is a conversation for your GP.

Can I use Genesis serum with other products?

Yes. It's a scalp product, so you can still use your usual conditioner, leave-ins and styling products on your lengths, including a night serum.

Where can I buy Kérastase Genesis serum in NZ?

From authorised Kérastase salons. UKIYO buys direct from L'Oréal New Zealand and ships nationwide from Wānaka, with free shipping over $75.

Every bottle we sell is bought direct from L'Oréal New Zealand and shipped from our salon on Helwick Street in Wānaka. Free NZ shipping over $75.