Beauty Hair Hair Products & Tools A Celebrity Hair Stylist Recommends This Growth Serum When Clients Want to "Thicken Up" Their Strands Shoppers say it’s like a “healthy vitamin for your scalp.” By Leah Groth Leah Groth Leah Groth is a lifestyle writer with over 20 years of experience covering beauty, fashion, health, and wellness. She’s contributed to various top publications and websites including VeryWell, Health, Glamour, and InStyle. InStyle's editorial guidelines Published on April 25, 2023 @ 11:00PM Pin Share Tweet Email We independently evaluate all recommended products and services. If you click on links we provide, we may receive compensation. Learn more. Getty Images. Photo: Getty Images Here’s an (unfortunate) fact: You are losing strands of hair every day. According to the American Academy of Dermatology Association, it's totally normal to lose between 50 to 100 strands of hair daily. However, for reasons ranging from health conditions and hormones to environmental factors, some people experience more hair thinning than others. Recently, I’ve noticed that my once super-thick head of hair is, well, majorly thinning out. Luckily, one of my closest friends also happens to be a Los Angeles-based celebrity hair stylist, Sean James, and he told me about a hair growth serum he recommends to all the A-listers in his little black book (which includes longtime client Jamie Lee Curtis and Riverdale’s Cole Sprouse). “I always recommend the Kerastase Initialiste Scalp & Hair Serum for my clients to thicken up their hair,” James, who works out of the Matthew Preece Salon in Santa Monica, tells InStyle. One of the main benefits of using Kerastase serum is that it helps to improve the quality of your hair by addressing issues at the root level, he explains. The concentrate infuses active ingredients, including plant-based stem cells, peptides, proteins, and hyaluronic acid into the scalp, “which work together to protect the hair from environmental stressors and promote hair growth,” James says. Kerastase Shop now: $58; kerastase-usa.com An added bonus? While it thickens and strengthens strands and minimizes shedding, the serum also leaves behind shine and luster. James says it’s suitable for all hair types, whether you have fine, color-treated, or damaged hair. Using it is simple, too: Apply it directly onto the scalp on cleansed, towel-dried hair (two full droppers for fine hair and four for thick) and evenly distribute it from the front to back of your scalp. Then just massage it in, comb through, and style as usual. Three applications a week is recommended by the brand. Kerastase promises benefits in just one week, and several customers back this up. One reviewer, who called the serum a “game changer” maintains that their hair “totally transformed from dry and dull to smooth and silky” after three applications. “I cannot imagine my life without Initialiste. It is definitely the best hair product I have ever used.” Another attested to having “healthier, lighter, shinier” hair after two weeks, while an “older” shopper with thinning hair swore that it helped prevent shedding. “I've been using this for about six months, and much much less of my hair falls out. It's like a healthy vitamin for your scalp,” they wrote. “Overall, if you're looking for a reliable product that can help to improve the strength, thickness, and shine of your hair, the Kerastase concentrate is definitely worth considering,” James says. Shop your own bottle of Kerastase’s Initialiste Scalp & Hair Serum for $58. Shop More InStyle-Approved Picks Shoppers Say Their Hair Looks “Fuller” and “Absolutely Gorgeous” Thanks to This On-Sale Growth Serum The “Most Flattering” Jeans From a Denim Brand Celebrities Wear on Repeat Are 65% Off at Amazon 67-Year-Old Shoppers Call Amazon’s Best-Selling $14 Concealer “Absolute Magic” for Erasing Dark Under-Eyes