As the name suggests, this best-selling duo is packed with biotin, alongside hydrolyzed keratin, to strengthen weak hair. Safe for sensitive scalps, you can expect to see shinier, thicker strands after a month of use.
Amazon rating: 4.3/5 stars
An Amazon reviewer says: “I have vibrant hair color (pink, blue, purple) and my hair is long and thinning in the upper corners. I also have a spot that has been balding on the side of my head for over a year now. HOWEVER, this does not wash out and fade my hair color, makes it feel super soft and clean AND after two months of using this, I’ve seen my hair grow back longer and thicker. Even little baby hairs have grown in my balding spot.”