If you've ever seen the words keratin, bond-building, or repairing stamped on your hair care labels, guess what? You probably have a protein treatment on your hands! These products are beloved for fortifying hair at the structural level, as the protein-infused ingredients can shimmy their way into the hair bonds and repair them from the inside-out (hello, salon-quality strands), but it's crucial you use them correctly. Overdo it on the protein, and you may wind up with hair that's even more brittle and strawlike (don't worry; we'll explain). 

If you're dealing with desperately dry, damaged hair, don't fret: This expert-backed guide will help your tresses spring right back to life. 

Fun fact: Your hair is actually made up of protein—about 95% of it, in fact, comprises the protein keratin. It's quite literally what gives hair its structure. But those amino acid chains can become broken over time—by heat styling, chemical processing, and other physical stressors (harsh brushing, too-tight hairstyles, and the like). That's where protein-infused products come in: These can help reconstruct those broken bonds, thus leading to stronger, smoother, and more defined strands. 

"A good protein treatment can aid in the repair of severely damaged hair, hair growth, and the penetration and healing of a dry, flaky scalp," says celebrity hairstylist Annagjid "Kee" Taylor. See, a major key to encouraging hair growth is protecting the length you already have, and having breakage-prone strands can make those hair growth goals nearly impossible. By strengthening and rebuilding those amino acid chains, protein treatments can protect the hair from damage and keep it healthy—and as a general rule, healthy hair grows way faster.

And when you strengthen the structure of those hair bonds, your strands appear shinier and softer, to boot. Not to mention, you can manage split ends (no, you cannot technically "mend" split ends, but protein treatments are great for sealing down the cuticle and preventing those splits from making their appearance).

If your hair doesn't have enough protein, it can appear dry, brittle, and strawlike. A lack of protein also affects the strands' elasticity, so Newman recommends what he calls the "stretch test." 

One important caveat: Yes, protein treatments can work wonders for brittle, damaged hair, but it is possible to overdo it, which (sigh) also results in brittle, strawlike strands. See, your hair has a delicate protein-moisture balance: "Your hair still requires a proper combination of moisture (which allows it to expand without breaking) and protein (which strengthens hair from the inside out)," says Taylor. "Overtreatment with protein can cause hair to lose elasticity, making it dry and brittle." It's a concept called "protein overload," and here's what to do about it, if you think you may have gone overboard.

You can find bond-building ingredients in a host of hair care products—shampoos and conditioners, leave-ins, and the like—but protein treatments will typically come in mask form, as they have a higher concentration of protein-infused ingredients to really repair those hair bonds. That said, they shouldn't be part of your everyday hair care routine, but here's how to fold one into your repertoire:

Like pretty much all matters of hair care, your curl pattern, porosity (aka your hair's ability to absorb and hold on to moisture), and styling habits can all affect how much protein you should include in your routine. 

For example, someone who uses hot tools on the regular might need to add more protein, as consistent heat styling can break down hair bonds and damage the cuticles. Additionally, "If you're one to wear your hair in a ponytail or high bun often, it's likely that your hair will experience breakage," notes Taylor, which may require more protein to help fill the gaps in the hair shafts. On the other hand, water evaporates rather quickly from high porosity hair, which means you may need to focus more on moisture than protein. Get to know your hair's unique complexities—we cannot stress it enough! (And here's a quick hair porosity test, if you're curious.)

Generally speaking, though: "It is safe to use a protein treatment weekly for the first month of using it," notes Fitzsimons. "After that first month, I wouldn't recommend using it more than once or twice a month, as adding too much protein in your hair can leave it feeling brittle and susceptible to breakage." If you'd like to break the schedule down further, catch Taylor's timeline below: 

Here, the protein treatments we adore right now.

Protein treatments are beloved for strengthening hair bonds, repairing breakage, and enhancing hair's smoothness and shine. Just make sure you're using these products correctly and keeping your hair type, porosity, and styling habits in mind—protein products work wonders, but remember, it's easy to get too much of a good thing.