I Tried "Hair Filler" & My Strands Have Seriously Never Looked Healthier 

I recently opted for hair filler. 

You might read that sentence and imagine some sort of syringe injecting my strands with cuticle-plumping ingredients, or a hair transplant treatment—but to be honest, dear reader, hair filler is way less scary than it seems. In fact, you've probably already dabbled in some hair-filling formulas yourself. 

When I say "hair filler," I'm talking about protein-rich ingredients that penetrate the strand and reconstruct broken hair bonds, leading to healthier, smoother, and more defined strands. If this sounds similar to a bond-building treatment, well, that's because that's exactly what it is—hair filler and bond-builders are essentially one and the same. 

"We can't recreate the exact protein that is in our hair [with topicals], but synthetic and naturally sourced proteins can repair and stand in place like a Band-Aid," NYC-based hairstylist Matt Newman says regarding bond-builders. These proteins help fill in the gaps between broken hair bonds for the time being. Hair filler… Get it? 

As you coat the strands with these bond-building ingredients (buzzwords include keratin, biotin, hydrolyzed quinoa, amino acids, bond-building, or silk protein) and rebuild those amino acid chains, you protect them from further breakage and strengthen their ability to withstand physical and environmental stressors. 

Plus, when you strengthen the structure of those hair bonds, your strands appear shinier and softer, with less noticeable split ends (protein treatments help seal down the cuticle, thereby preventing splits from making their grand entrance). 

I will always hold a special place in my heart for Garnier Fructis. It's a brand I grew up with, and the lime green bottles take me back to roaming the drugstore aisles, contemplating which formula would help me achieve the elusive hair-commercial-level locks. I ended up a devout Sleek & Shine girl and remember marveling at how soft my hair felt after each wash—like silk. 

The difference lies in the updated formula. For the full collection, Garnier has committed to cleaner, more responsible formulas for the full collection, all products cruelty-free and without sulfates, parabens, phthalates, and DMDM hydantoin (a formaldehyde-releasing preservative).

This Hair Filler treatment also skips mineral oil, an ingredient that commonly helps with moisture retention and decreases frizz but can also cause buildup and clog the hair follicles. 

Again, this is a pre-shampoo treatment, meaning, you'll use it as step one in your shower lineup. That may sound like a commitment, but you don't even need to hop out of the shower once you apply (whereas some bond-building formulas require a 20- to 30-minute marinating time). 

Wet your hair, apply the treatment, and let it sit for 5 minutes before rinsing out—just enough time to use a body scrub, shave, contemplate your life choices, etc.

Just remember that hair filler is an intense protein treatment, and you don't want to overdo it. The exact cadence will depend on your hair's porosity and breakage level, but as a general rule, save it for a deep treatment once or twice a month.