I Tried Olaplex’s Buzzy New Hair Serum & I Have *Thoughts*

In our series Trial Run, TZR editors and writers put the buzziest new beauty products to the test and share their honest reviews. This week, our beauty writer is testing the new OLAPLEX No. 9 Bond Protector Nourishing Hair Serum.

Hair titan, OLAPLEX makes free-radical-fighting history today by releasing its new No. 9 Bond Protector Nourishing Hair Serum, a water-soluble serum that provides antioxidant protection against pollution and free radicals while adding moisture to dry strands and mending broken bonds. Phew, that was a mouthful, but this product really *does* wear many hats.

I know what you might be thinking: is pollution really *that* bad for the hair? Dr. Joshua Zeichner, associate professor of dermatology and director of cosmetic and clinical research in dermatology at Mount Sinai Hospital reveals to TZR, “[pollution] can cause free radical damage which contributes to premature graying, weakness of the hair shafts themselves, and dulling of hair color. Oxidative stress from pollution may also contribute to hair thinning.”

In addition to protecting your tresses against the many free radicals that are out in the world, this serum also contains hydrating ingredients to add moisture to dry hair, and film-forming polymers to provide additional protection against damaging pollutants while adding shine and reducing frizz. Given that I live in a major metropolitan city (NYC), and my dry hair just so happens to reveal more split ends each and every day, I decided to give the No. 9 Bond Protector Nourishing Hair Serum a whirl. Here’s are my thoughts.

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Fast Facts

• Price: $28
• Best for: Protecting the hair from pollution damage and rebuilding broken bonds.
• Your rating: 4.5/5
• Brand: OLAPLEX
• Clean/Cruelty-Free? Yes
• What we like: Its lightweight texture and seamless introduction to my hair care routine.
• What we don't like: The antioxidant protection in this product lasts 48 hours and you can only use it on damp hair. This means you’ll have to wet your hair in between washes to reapply this. (Re-wetting the hair might not bode well for people who only wash their hair once a week.)

My Dry, Limp, City Hair

I’ve always managed to keep my 2B curls healthy from root to tip when my hair was shorter, but now, with my hair reaching below my chest, I’m finding it more and more difficult to maintain moisture and keep split ends at bay. Additionally, although I’m sure I’d never call another city home, NYC’s atmosphere is not the best for my beauty routine. My hair (along with my skin) suffers from pollution, which is evident through my frizz, loss of shine, and limp texture.

OLAPLEX No. 9 Bond Protector Nourishing Hair Serum

So, what makes my (and possibly every beauty editor’s) ears perk up at the launch of the OLAPLEX No. 9 Bond Protector Nourishing Hair Serum? Much like OLAPLEX’s other products, the No. 9 serum contains the brand’s multi-patented bond-building technology, Bis-Aminopropyl Diglycol Dimaleate to mend frayed hair.

What sets this leave-in product apart from the brand's other styling products is its ability to ward off free radicals and repair current damage caused by pollution in all hair types.

The Science Behind Olaplex No.9

Let’s get into the nitty-gritty of how exactly this serum works, shall we? First, it contains hydrating ingredients like hyaluronic acid and panthenol that bind to the strands to add moisture to dry and damaged hair. The star of the show, however, is red algae from the South of France, which, “is a very strong antioxidant that protects against different free radicals,” according to Lavinia Popescu, chief scientist for OLAPLEX. This gives the serum the ability to soak up any unwanted free radicals before they reach your hair, much like your favorite antioxidant serum would do for your skin.

Plus, this formula contains film-forming polymers that neutralize free radicals for up to 48 hours and even guards the hair against heat styling up to 450° Fahrenheit. Dr. Zeichner adds, “Polymers in hair care products coat the surface of the hair to hydrate, protect, reduce frizz, and improve shine of the hair.”

My First Impression Of Olaplex No.9

When I received the serum, I must admit that it was a great unboxing day. For starters, I was shocked at how big this product is — at a whopping 90mL, it’s about two times bigger than most hair serums I currently have in my collection.

I was also impressed by how lightweight the texture is: it has the same consistency of a water-gel serum that one would use on the skin, without any slimy, oily residue that most hair products in its category tend to offer. Plus, it’s virtually scent-free, making it great for those who are sensitive to fragrances.

How To Use Olaplex No.9

Popescu recommended I apply the No. 9 serum to damp hair, starting at an inch away from the scalp and going down to the ends (when the chief scientist for OLAPLEX tells you to do something, you listen). Popescu reveals that it is critical to apply this serum to damp hair, stating, “while the hair is wet, the cuticles are more open, and the product can make its way underneath the cuticles and protect from pollutants both the outside and the inside.” I use it after every wash since I wash my hair every two days. If you *do* wash your hair less frequently than I do, OLAPLEX recommends re-wetting your hair in between washes to reapply this every 48 hours.

Since this formula is water-soluble, it is fairly thin — it’s best to use it right at the start of your hairstyling routine, before applying any other creams or oils.

The Results

After my initial application, I was pleasantly surprised to see that my hair didn’t look or feel weighed down at all. It was as though there was nothing in my hair, but I could see that my curls looked shinier and healthier. I didn’t notice a ton of added definition in my texture immediately, but after using this product plus a hair oil for three weeks, my curls are more defined, and my ends look and feel stronger. Plus, the results are long-lasting — my hair remained soft and shiny in between washes.

Is Olaplex No.9 Worth It?

I’d definitely say that the OLAPLEX No. 9 Bond Protector Nourishing Hair Serum is worth both your time and money. This serum costs a comfortable $28 for 90 mL, which is in the median price range for most hair serums with almost double the amount of product as others on the market. It’s an effortless addition to my hair care routine since it’s *so* lightweight, easy to apply, adds shine right off the bat, and adds texture to my hair while repairing my ends in the long run. Plus, it helps to shield my hair from pollution and free radicals, which is welcome for my NYC lifestyle.

Product Specifications:

Product name: OLAPLEX No. 9 Bond Protector Nourishing Hair Serum

Ingredients: Sodium Hyaluronate, Panthenol, Red Algae Extract, Polymers, Bis-Aminopropyl Diglycol Dimaleate

Size: 90 mL/3.0 fl. oz.

Suitable For: All hair types.

BDG product reviews and recommendations are written and conducted by writers and editors with expertise in their fields. Testers often have specific experience with the situation or product at hand, and/or their review or recommendation is provided in consultation with experts. You can learn more about our standards here.