Beauty Hair Hair Products & Tools Shoppers With Thinning, Aging Hair Say This French Shampoo Reverses the March of Time “I couldn't find a single product that helped even a little, until I found this line.” By Rachel Nussbaum Rachel Nussbaum Instagram Twitter Rachel is a journalist, writer, and editor who specializes in the beauty and wellness industry, writing about the best, safest products the industry has to offer for InStyle, Byrdie, and Shape. InStyle's editorial guidelines Published on July 11, 2021 @ 10:00PM Pin Share Tweet Email We independently research, test, review, and recommend the best products—learn more about our process. If you buy something through our links, we may earn a commission. Photo: Rosdiana Ciaravolo/Getty Images I am always, always on the lookout for a good hair growth shampoo. As much as I love my curly hair, detangling it is a beast — and while the ordeal's gotten miles easier since welcoming an electric comb into my life (pry it out of my cold, dead hands), at the end of the day my shower's drain catcher wears a sizable toupee. So my eyes lit up when I happened upon the Rene Furterer Triphasic Strengthening Shampoo that cuts down hair loss like a pro. The French brand takes a unique approach to its hair thickening technique; instead of using something like biotin, its shampoo relies on a combination of "ATP Intensif" — also known as adenosine triphosphate — and castor oil, pfaffia extract, and essential oils. According to the brand, ATP helps to maintain existing hair's life and kickstart the growth phase, providing a two-prong block to gradual and sudden hair loss. Hair growth products are a breeding ground for snake oil ingredients, but according to a 2015 study of 102 people with male pattern hair loss, the group that used ATP improved 80 percent, compared to the control group's 32 percent. Hair also turned out significantly thicker in the ATP-treated group, which is great news — however, Dr. Rachel Nazarian, a board-certified New York dermatologist, notes that participants were treated twice a day, so it's not quite a one-to-one comparison. Courtesy Shop now: $32; renefurtererusa.com Switching gears, Dr. DiAnne Davis, a board-certified cosmetic dermatologist, has previously told InStyle that castor oil is helpful for hair growth, since it can increase blood flow to the hair follicles while making your hair look more glossy. "Oils can help scalp health in multiple ways, primarily as it hydrates the cuticle to avoid breaking," adds Dr. Mona Gohara, an associate clinical professor of dermatology at Yale's School of Medicine. "They also can decrease inflammation and dandruff, which can be a cause of hair loss." According to shoppers, the results speak for themselves. "I had immediate results. I had dreaded washing my hair because so much would end up over the drain and in my brush," writes one person. "No more. My hair is lovely and soft, and I have no scalp itch." Other people agree that the effect was stunningly fast, even thinning temples thickening with the shampoo and matching conditioner. "I have been looking for 'the perfect shampoo' as part of my regimen to combat my aging, thinning hair," writes another fan. "Wonderfully cleansing without stripping, no harsh smell, excellent consistency. This is the shampoo I have been looking for." Others say that their hair definitely feels stronger, shinier, and more voluminous, while hair loss during washes has petered out. And as a bonus, another person says it helps them extend how long they can go between showers. Those going through other health trials also found relief, per a reviewer who was being treated for endometriosis. "My hair started falling out by the handfuls. Within two months, I lost 40 percent of my hair," they write. "My scalp was inflamed, hair shedding like crazy, severe itching and breakage. I couldn't find a single product that helped even a little, until I found this line. I noticed today that I have new hair growth popping up at my hairline that definitely wasn't there before. I will be buying the biggest bottle." A different person goes so far as to dub the effects "magic," especially when used in tandem with the brand's whole system. Those with "incredibly fine and thin hair" say it's the first shampoo that doesn't make them hate their hair, and it works so well, one shopper's stuck with it for 30 years. "Saved my hair. About six months ago my hair started to really show its age, including thinning, breaking, and dullness," writes a last reviewer. "This shampoo has done wonders for me. I don't think I'll ever use another shampoo for the rest of my life!" Searching for more hair growth help? This Best-Selling Hair Growth Serum Now Comes as a Dry Shampoo Amazon Shoppers Say This Dermatologist-Approved Biotin Serum Is Better Than Rogaine Shoppers Say This $11 Hair Product Makes Hair Grow Out 'After Over a Decade of Trying'