This French Split-End Serum Made My Hair the Softest It’s Been All Summer (and I Haven’t Cut It Since April)

Let’s face it: split ends are the enemy of every woman with dry, thirsty hair. But for curly girlies like myself, they can be particularly unruly. Still, I haven’t cut my hair since April (who has the time!) and after months in the sun and saltwater, it’s starting to show. My ends are tired. They’re no longer smooth or moisturized, while the rest of my hair feels more coarse in general. Which is why it was time for a hair care shake-up.

The Kerastase Nutri-Supplement Split Ends Serum ($45) proves to be a true warrior in the battle against my dry, dead tendrils, effectively coating my split ends with a silky, nourishing layer that makes my hair look like new the moment it dries. This serum goes beyond mere aesthetics; it penetrates deep into each strand, ensuring that my hair is not just temporarily patched up on the outside, but genuinely nurtured back to health. Its lightweight formula creates a shield of protection of sorts, preventing further damage while giving split ends a chance to heal.

Kérastase, Nutri-Supplement Split Ends Serum — $45.00

Pros: 

• Coats split ends for softness and shine
• Nourishes and strengthens with plant proteins
• Hydrating, but not too heavy or greasy
• Infused with scalp-boosting niacinamide
• Convenient dropper bottle

Cons:

• Expensive for a small bottle (50 mL)

How it works

Among the impressive lineup of ingredients, niacinamide stands out as a secret weapon in this serum. A form of vitamin B3, it’s commonly used as a brightening, barrier-boosting agent in skin-care products, but is also great for hair health. Niacinamide’s ability to enhance the skin’s barrier function extends to your scalp, ensuring a healthier environment for hair growth and stronger, happier strands.

There’s also a burst of plant-based proteins in the formula, which work to zip up unruly split ends and “coat” them for a smoother, silkier look and feel. Hair is primarily composed of a protein called keratin, which provides the structural framework for each strand. Protein-based products work by binding to the surface of the tendrils, replenishing each strand to improve its texture, strength, and appearance.

Together in one, potent concentrate, the Kérastate Split Ends Serum instantly seals split ends for shinier, healthier hair, all while adding a burst of long-lasting hydration for long-term healing.

Why I love it

From the very first time I combed this serum through my strands, I was struck by how effortlessly it coated my split ends. My curls—which had been left parched and lifeless after a summer of UV rays, heat, chlorine, and saltwater—have found new life and feel softer, bouncier, and beautifully renewed.

What sets Kérastase’s Split Ends Serum apart is its unparalleled hydrating power. The oil absorbs like a dream, delivering an infusion of moisture that feels like a tall drink of water for my thirsty follicles. All I do is squeeze a few drops of the oil into my hands and run it through my wet strands, which instantly hydrates them post-shower. The best part? The moisture doesn’t evaporate into thin air. It stays with me throughout the day, even through the next day, ensuring that my hair remains touchably soft and incredibly nourished for hours on end.

I’ve put this serum to the test for a full month, and the results have been nothing short of astounding. My hair has undergone a noticeable transformation; my individual curls are shinier, smoother, and more defined than they were before using Kérastase’s treatment. Specifically, the ends aren’t nearly as ratty as they were four weeks ago, which is a testament to how well this stuff actually works.

My only complaint is that it’s pretty expensive for the amount of product you get. A 50 ml. bottle is currently $45 which isn’t that much bang for your buck. I have thick hair which means I naturally use more product—after a month of using every other day-ish, I have about half the bottle left, maybe even a little less. That said, I try to use it sparingly to savor every moment, I love it so much. Even if I do run out, I’ll probably buy another bottle—these days, $45 is cheaper than a haircut, after all.