15 Best Hair-Thickening Products to Transform Fine, Flat Strands
Major volume and fullness, coming right up!
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Every year I make the same birthday wish: To magically wake up with thicker, fuller hair. (Spoiler: It has yet to come true.) Which is why I’ve tested more than 100 of the best hair-thickening products out there in my adult life, from hair-growth vitamins to hair-thickening shampoos to hair-growth oils—all in an effort to make my fine hair look denser and more voluminous. To aid in my quest, I consulted three experts: certified trichologist William Gaunitz, celebrity hairstylist Andrew Fitzsimons, and synthetic biologist and beauty expert Evan Zhao to get to the root of the problem and what I can do to fix it.
There are a ton of products out there that can be used to improve your current flat-hair state, and they all work differently. As Fitzsimmons tells Cosmo, “Products like hair-thickening shampoos work by adding volume to the thinner, flatter strands to temporarily give more lift to the overall appearance of the hair.” Gaunitz further adds that he’s found thickening products to be especially effective when they're using chemical volumizers to blow out the cuticle, which is the protective scale-like layer on the outside of the hair shaft. “When a hair-thickening product opens the cuticle,” he tells Cosmo, “it in turn enhances the overall size and diameter of the hair shaft.” And when shopping for hair-thickening products, Fitzsimmons recommends looking for ingredients such as Keratin, caffeine, collagen, or biotin.
Trust me, I know this feels like a lot of info to digest! That’s why I’ve gone ahead and done the research for you to find the very best products you should add to your lineup, and I promise they won’t disappoint. Take a peek at some of my findings below.
Our top picks for the best hair-thickening products in 2024:
Now keep scrollin' for our complete list of hair-thickening products below, featuring reviews from real-life testers who have all waxed poetic about these gold-star formulas. And if when you make it to the very end, read on for expert insight into how to narrow your search to one product and more.
Daisy Maldonado is an associate shopping editor at Cosmopolitan who loves writing about fashion trends, must-have beauty products, and digital culture. When she's not writing, you can almost certainly find her shopping (she knows her credit card numbers by heart) or obsessing over celebrity news. Although she’s acquired an extensive closet over the years, her favorite item she owns is a Harry Styles Love On Tour hoodie she purchased at his concert in Manchester. Daisy's work has appeared on Refinery29, The Daily Beast, E! News, Allure and more. Keep up with all of her chaotic travels, NYC life and fashionable moments on her Instagram.
Marisa Petrarca is a contributing beauty writer for Cosmopolitan.com. In the rare case that she’s not working on a story, you can find her testing new makeup, skin, or hair launches, binge-watching bad reality TV, or diligently working (but failing) to get her inbox to zero. Her work has appeared on The Zoe Report, POPSUGAR, and GRAZIA USA, among others. Follow her on Instagram for corgi photos and shameless self-promotion.
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