Dakota Johnson's effortlessly tousled brunette hair is one of her most defining features, and now we know maintaining those glossy, healthy strands takes more than good genetics. The Madame Web star reportedly keeps her hair in top form with a cult-favorite supplement that's available on Amazon. According to Marie Claire, Johnson takes Nutrafol Women's Balance Hair Growth Supplements to keep her iconic strands long and healthy. You can get undone-yet-glamorous hair with this formula that's designed to promote growth and shine from the inside out. Get it See it: Nutrafol Women's Balance Hair Growth Supplements at Amazon! Please note, prices are accurate at the date of publication but are subject to change. Nutrafol is beloved by celebs, stylists and dermatologists alike for its clinically tested ingredients that target the root causes of hair thinning, including stress, hormones and aging. Formulated with medical-grade botanicals like ashwagandha, saw palmetto and marine collagen, these capsules help improve hair growth, thickness and strength in as little as three months. Reviewers Say This Hair Growth Mask 'Is Legitimately the Only Thing That Has Ever Helped Hair Grow' As someone who has used Nutrafol in the past, I can attest to how quickly you'll see results (not to mention how easy it is to add this supplement to your routine). Like many women, I experienced hair loss after giving birth to my daughter. I added Nutrafol to my daily supplement regimen and noticed thicker, fuller hair after just three months! Unlike quick-fix gummies, Nutrafol works from within to balance the body's natural hair-growth cycle. Each serving helps boost scalp health and encourage stronger follicles, resulting in fuller, more resilient hair - something Johnson's soft, voluminous waves prove effortlessly. One Amazon reviewer called the hair growth supplement "the top product for women with hair thinning and hair loss," and confirmed it's well worth the price. "You start seeing results in three months." Another reviewer said Nutrafol "exceeds expectations" and that they've "stopped shedding" and have hair that "feels and looks fuller." It's no wonder Johnson's signature hair always looks camera-ready. With Nutrafol in her routine, she's giving her locks everything they need to thrive from the inside out, and now you can too! Get it See it: Nutrafol Women's Balance Hair Growth Supplements at Amazon! Please note, prices are accurate at the date of publication but are subject to change. Looking for more healthy-hair heroes? Explore more from Nutrafol here, and check out top-rated hair growth vitamins on Amazon. Don't forget to browse Amazon's Daily Deals for more beauty must-haves! Bethenny Frankel Says These Hair Growth Supplements Actually Work Us Weekly has affiliate partnerships. We receive compensation when you click on a link and make a purchase. Learn more!