My hair and I have a love-hate relationship. While I enjoy my length and fullness, the untamable frizz and coarse texture are things I can never get past. to the point where I’m constantly blow drying it straight and my 2B curls rarely see the light of day. I’ve never color-treated my hair before, but I have subjected it to its fair share of trauma — namely, months of chlorine exposure, more than two decades of heat styling and a lifetime of tight hairstyles. Needless to say, my hair is severely dry.
Recently, Olaplaex sent me its No.5 Moisturize & Mend Leave-In Conditioner, a formula that sounded like it could reset my frizz-prone, dehydrated hair.
Below, I share my experience using the product — which debuted in August 2024 — including its ingredients, who it’s best for and how to apply.
SKIP AHEAD How I tried Olaplex’s No.5 leave-in conditioner | My experience with the No.5 Moisturize & Mend Leave-In Conditioner | Who is Olaplex’s leave-in conditioner best for? | Why Trust NBC Select?
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What is Olaplex’s No.5 Moisturize & Mend Leave-In Conditioner?
Olaplex No.5 Moisturize & Mend Leave-In Conditioner
As pioneers in the hair care space, Olaplex put bond building technology — that is, technology designed to strengthen and rebuild weakened hair bonds — on the map. Hair bonds are what give the hair its shape, durability, elasticity and shine, and coloring, chlorine exposure, chemical treatments, daily styling and humidity can damage them. Olaplex products, including its No.5 Moisturize & Mend Leave-In Conditioner ($32) work at a molecular level to repair damage, lock in hydration and protect it from moisture loss.
The leave-in conditioner also uses a sealing complex to help mend split ends. While it works for all hair types, it’s especially beneficial for those with dry, damaged hair that’s in need of moisture, according to Olaplex.
Olaplex has another leave-in product, the No.6 Bond Smoother, which also aims to hydrate and smooth the hair, but it’s more of a styling cream that hones in on frizz control and definition, while the leave-in conditioner hydrates, repairs, mends split ends and protects hair from damage, according to brand.
How I tried the Olaplex No.5 leave-in conditioner
Over the course of three weeks, I tried the leave-in conditioner in several ways: on air dried and damp hair, on damp hair that I then heat styled and in between washes on already-styled hair to refresh. Leave-in products typically clump up on my curls, leaving behind residue and greasiness, so I was determined to see how this product fared particularly when I blow out my hair.
For reference, my Middle Eastern 2B hair is extremely dry from scalp to ends. It’s also prone to frizz — even when I blow it out, it frizzes up when exposed to the slightest humidity. My typical hair care routine involves using a shampoo and conditioner combination (right now that’s the Morrocanoil Hydrating Shampoo & Conditioner, the Moroccanoil Treatment Original and the Drybar Liquid Glass High-Gloss Finishing Hair Serum). After blowing out my hair, I usually follow up with a lightweight hair spray, like the Drybar Seltzer Spritz Flexible Hold Hairspray.
Olaplex recommends starting with one pump if you have fine hair and two pumps for medium to coarse hair, adding more as needed onto clean, damp hair. Then, you can proceed to air dry or heat style. On hair wash days, I use three pumps on my long, thick hair, working the product starting just below the roots and all the way to my ends (avoiding my scalp). When my blown out hair needs frizz control, I applied one to two pumps from the mid-length to my ends and my hair looks freshly styled.
My experience with the Olaplex No.5 Moisturize & Mend Leave-In Conditioner
Despite Olaplex’s popularity — particularly its No.3 Hair Perfector and No.7 Bonding Oil I’ve never remained committed to the brand because I always assumed it was geared more for those with color-treated hair. That’s why when I saw that the leave-in conditioner was made specifically for anyone with dry hair (even those with virgin hair), I was instantly drawn to it.
What I like
Doubles as a styler
After testing this leave-in for a few weeks, I have been pleasantly surprised to see that it far exceeded my expectations. While it’s not marketed as a styling product, that’s exactly what I’ve been using it as. The formula defines my curls and makes them appear more uniform without weighing them down, and it instantly removes all traces of frizz upon application, making my hair appear sleeker and shinier. I’ve worn my hair in its natural state several times since incorporating this into my routine, and it feels good knowing that it’s enhancing my curls while also repairing and protecting my hair from damage.
Moisturizes dry ends
As for my ends, which are typically straw-like, the leave-in conditioner makes them appear more hydrated and healthy. I’m the type to get frequent trims (once every six months), but I can see this formula extending the time in between haircuts because of how nourished it makes my tips look. In fact, it almost feels like a lightweight hair mask for my ends.
When getting a blow out, I always ask for round brush curls because I’ve found that the curls help mask my dry, split ends than if I were to just have it styled straight. Because of how moisturized this leaves my ends, though, I’m more confident sporting straight, non-curled hair.
Easy application
The pump applicator disperses just the right amount of product that doesn’t leak, which is something I appreciate. I also like that the pump has a slight grip to it, which is helpful if you find yourself needing to pump out more after already having residue on your hands from the first application. Aside from this, the product doesn’t feel too sticky, and I don’t feel an absolute need to rinse my hands afterward, making it great for keeping in my gym bag or car.
Drawbacks to keep in mind
Not travel-friendly
While the amount of product in the bottle is TSA-friendly, the packaging is quite bulky and may take up a good amount of space in a toiletry bag. It currently doesn’t come in a mini option, and I’m not sure how likely the brand is to produce one, considering it carries several jumbo value size products, and their mini size offerings only include the No.4 Bond Maintenance Shampoo, No.4 Bond Maintenance Conditioner and two sets). While the packaging feels durable and the cap fits securely onto the bottle, it doesn’t have a lock on the pump for those who plan on traveling with it.
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Who is Olaplex’s No.5 leave-in conditioner best for?
Overall, I highly recommend Olaplex’s leave-in conditioner for anyone struggling with hair damage or those looking to reintroduce moisture into their hair. It’s definitely suitable for all hair types (fine included) since it doesn’t weigh the hair down or make it feel greasy. It’s also great for those with bleached, colored or otherwise chemically treated hair, and can work for those with wavy to slightly curly hair types like mine who want to hydrate and define curls.
Scent-wise, the formula has a sophisticated bubblegum aroma that lingers in my hair even after heat styling (something that’s rare for my hair), so if you’re not someone who prefers scented products this won’t be for you.
As for pricing, the formula is more costly than drugstore alternatives like the Not Your Mother’s Tough Love Intense Bonding Treatment ($11) or the Eva NYC Mane Magic 10-in-1 Split End Mender ($16) — Olaplex’s formula is $32 for a 3.3 fluid ounce bottle. For a treatment that’s thicker and specific to curls, the SheaMoisture Bond Repair Leave-In Conditioner ($13) may be a good alternative that’s less costly.
Why trust NBC Select?
I have more than 10 years of experience covering beauty and skin care topics and frequently try and review new products. For this story, I tested the Olaplex No.5 Moisturize & Mend Leave-In Conditioner for three weeks, considering the ingredients, how it performed on my dry, curly hair and who it might be best for.
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