The Scalp Treatment Giving Users Full, Healthy Hair for the "First Time in Decades" Is Back in Stock

As someone with fine-to-medium hair that sheds a lot, I'm always on the lookout for products that will encourage growth, but most importantly, keep my scalp healthy and balanced. The scalp is, afterall, the (literal) laying ground for happy strands. When it comes to hair care brands that take that scalp-first approach, Act+Acre is one of the best on the market — that's why it's no surprise that its growth-stimulating scalp treatment has been sold out for nearly three months. The good news? The Stem Cell Serum is finally back in stock, and shoppers are ready to "hoard" it.

The Act+Acre scalp treatment is a plant-based serum that focuses on extending the natural hair-growth phase, lessening hair fallout, and soothing the scalp. Made with apple stem cells, aloe vera, and bamboo and pea extracts, the serum can be considered an "anti-aging treatment" for your hair, according to brand founder and trichologist Helen Reavey. "Over time, the scalp begins to produce less collagen, hair follicles get smaller, and the rate of hair growth slows. This can result in less hydrated and thinner hair, with increased fallout," Reavey tells InStyle. "Consistent use of an anti-aging treatment, especially one including apple stem cells, protects the longevity of the scalp to combat the natural aging process."

Shop now: $86; actandacre.com

Reavey explains that apple stem cells, which have anti-inflammatory and antioxidant properties, "are clinically proven to stimulate hair growth." "When added to your scalp care routine, this unique ingredient elongates the process in which the hair sprouts from the follicle," she says. "Extending the growth cycle [can lead] to an increased amount of hair follicles and longer hair."

Customers are impressed with the serum's results, claiming it's relieved scalp itchiness, aided in hair growth, and reduced shedding. One shopper, who described their "middle-aged" hair as "dry and brittle," said they almost gave up on products to help revive their strands until trying Act+Acre's treatment. "After six months of use, my hair is full, healthy, growing (new and old growth), and shiny for the first time in decades," they wrote.

Another shopper raved that after trying the Stem Cell Serum combined with the brand's Hair Cleanse, they "awoke with a different head of hair." "It works," they wrote. "My scalp and hair are healthier…and my long, naturally gray hair shines; the color even looks fresher. These products do a superb job."

No wonder it amassed a waitlist of more than 18,000 people. Add the Act+Acre Stem Cell Serum to your hair care routine before it sells out (again).