On this note, anything that can help repair and seal the cuticle will help you get shiner hair. The cuticle is the outermost layer of the hair strand, and it’s made up of tiny overlapping keratin fragments (the most common analogy is shingles on a roof). When these lie flat, hair is less frizzy, better able to hold in moisture, and appears shinier. When your cuticles are damaged—be it from chemical processing, heat styling or physical damage—it can make hair appear duller.
“To understand damaged hair, it’s important to know how hair works. Most hair is made of three layers: the inner fiber called the medulla, the middle layer called the cortex, and an outer layer called the cuticle,” hairstylist Josh Rosebrook explains. “When hair becomes damaged, the cuticle raises, chips, becomes fragile, easily tangled, and loses moisture, luster, and the shine that’s created when the cuticle is flat and smooth.”
The issue, however, is that you can never truly repair damage—you can only cut off the damage or use products to help minimize the appearance. If your hair is shiny at the root but gets progressively duller toward the bottom, it may be a sign it’s time for a trim to snip off dead and split ends. If your damage appears all over (some people just have damage-prone hair; it happens), you’ll want to take every precaution to avoid worsening the issue and use repair-specific products, like protein-infused shampoos and conditioners.