This French Scalp Serum Is Why My Hair’s Suddenly So Thick and Healthy

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links."

It feels as though the methods for making hair look thicker, longer, and more luscious are endless. From soaking hair with rice water to dousing scalps in rosemary oil , there are no lengths people won't go to—including me. I never considered myself someone who suffered from hair thinning or shedding, but I have noticed a bit of volume loss and more strands coming out in the shower lately. It wasn't until I was in Paris earlier this summer and had a scalp analysis that I realized it was time to pay attention to my scalp health. After all, healthy hair starts at the scalp, and I am just in luck because there's a new powerhouse scalp serum on the block.

I love any French beauty secret, so when I found out that Hair Rituel by Sisley, the French brand known for its plant-based, science-backed haircare, revamped its iconic scalp serum, I was first in line to try it. The original Revitalizing Fortifying Serum used plant botanicals, such as sage extract to boost microcirculation of the scalp and boost hair growth, rice proteins to strengthen hair strands, and wheat extracts to protect color, but the new advanced formula, the Revitalizing Fortifying Super Serum Advanced Formula, focuses more on the scalp barrier and a healthy microbiome to get to the root of the problem (quite literally).

"While the gut and skin microbiomes are well understood, there had been a gap in knowledge of the scalp microbiota—until now," Pauline Poussin, the brand's scientific communications manager, tells me. After five years of extensive research, Hair Rituel discovered two bacterial strains that increase hair growth, even in areas affected by triggers such as alopecia. "These bacteria [strains] trigger hair follicles that are dormant from chronic inflammation, which contributes to hair loss," Poussin adds. Just like the microbiome on your skin, your scalp benefits from ingredients that create good bacteria, like the aforementioned strains, and decrease stressors that may cause inflammation to the scalp.

Although the serum is lightweight, the formula packs a punch, with five additional ingredients that make it even more powerful than the original. The first is ginger extract, which has been found to significantly reduce inflammation and balance the scalp microbiome, followed by vitamin B12, which gives the serum its pink hue, soothes the scalp, and protects it from aggressors like heat.

"Just like caring for fertile soil, maintaining an optimal skin environment is essential for the growth of strong and beautiful hair," Poussin says, adding that the microbiome is just one pillar in the formula. "The Super serum goes even further by simultaneously targeting hair longevity." The peptide craze continues as the brand features a tetrapeptide to increase hair thickness and strength—plus, amla extract to combat gray hairs and yeast extract to boost hair density.

I've been quite wary about scalp serums since most weigh my hair down and disrupt my style, but after testing this serum for a month, I am shocked at how easy it was to incorporate into my routine. The serum has the weight of water and instantly sinks into my hair. While it leaves my hair slightly damp, it dries shortly after—or I'll use a blow-dryer to speed up the process. The formula has strong botanical notes of mimosa flower and pepper, which can be strong if you're sensitive to scent, but it didn't bother me. The best part about this serum is that it can be used on wet or dry hair.

The Revitalizing Fortifying Super Serum Advanced Formula is available now at sisley-paris.com and retails for $280.

You Might Also Like

• Grace Jones's Career in Photos

• Michelle Pfeiffer's Style Evolution Through the Years

• Goldie Hawn's Style Evolution Through the Years