It is, in effect, a bandage. Romanowski agrees: “I’m skeptical that bond builders help very much, even if they do create some new hair bonds. I think it is just a bit of ‘science washing,’ because when you break the hair bonds you rearrange the molecules in such a way that you can’t easily restitch bonds in the proper spots.” It seems a majority of the effectiveness of these products are the conditioning ingredients, he adds, which can indeed improve the look and feel of damage.

If you have very bad damage, or even hair loss, see a dermatologist to talk about scalp and follicle health — creating a healthy environment for new growth means healthier hair as it grows.

How should I decide which bond repair products to use?

If you want to give bond repair a try, go for it — when used properly, these products won’t actively hurt your hair. Too much protein can dry out your hair, says Dr. Osted. But typically, the proteins used in hair products are hydrolyzed proteins, meaning they are water-soluble, says Romanowski. “Unless you are using a leave-in product, nearly all of the protein is simply rinsed down the drain. Again, it is just a compelling marketing story that proteins are helping your hair.”

But the “bond building” products on the market today can still provide nourishing conditioning ingredients to damaged hair, like behentrimonium chloride, dimethicone, and silicones, which Romanowski says “are really good at mitigating hair damage.”

When in doubt, ask your stylist. “Sometimes people aren’t sure of what products to use, and make assumptions about what products they need which can cause more problems,” says New York City-based hairstylist Stephen Thevenot. “Your stylist has a wealth of knowledge and can help you come up with a plan to treat your hair. There likely isn’t going to be a one-product-fix-all solution.”

Rinse-Out Treatments

“This treatment is packed with vitamins A and E and 18 essential amino acids,” says Toth, hence the “20” in the name. It also coats hair in lipids, which protects hair from pollution and environmental damage.

Toth appreciates that this rinse-out treatment offers “ hydrating ingredients like avocado, coconut, and green tea seed oils.” It also smells like a lush Balinese garden, which is reason enough to work this into our routine.

Shampoos and Conditioners

It smells like a fancy French salon without the fancy prices. (Now that’s chouette.) Even better is how it can deeply condition your hair at just the first step of your routine — eliminating the need for another treatment. (Though, we won’t discourage you from indulging in a hair mask just for self-care.)

Kenra Professional’s Triple Repair line is new to the market and includes a shampoo, conditioner, and serum. We’re particularly into the shampoo, since in addition to “bond-building” amino acids (which are good for hair health even if they aren’t creating new bonds), it has peptides to protect hair from more damage down the line.

This new color-safe, affordable conditioner is great for curly or coily hair, thanks to super-nourishing amla oil and shea butter (which may weigh down straight or fine hair types). It’s also formulated with amino acids to help repair damage from heat, color, and protective styles.

Leave-In Treatments

This leave-in treatment has a lightweight gel texture and thanks to hyaluronic acid, is particularly healing for dry or frizzy hair types. “I love that it gives hairstyles some hold and will help to define curls,” says Toth. While it’s not a bond builder (or “filling” any gaps, perse), it can help to improve visible damage.

There’s a lot of guesswork when it comes to finding ingredients that your hair responds to, so we love that this hybrid serum-cream treatment can be adapted to your hair type (straight and wavy or curly and coily) via customizable shots. Senior editor Jesa Marie Calaor loves its lightweight texture and how it defines her medium-coarse, wavy hair.