Olaplex

No. 6 Bond Smoother.

About this product

A leave-in serum designed to strengthen hair and protect against split ends and damage.

Full ingredients

Water, Cetearyl Alcohol, Dimethicone, Isohexadecane, Coco-Caprylate, Neopentyl Glycol Diheptanoate, Behentrimonium Chloride, Isododecane, Phenyl Trimethicone, Propanediol, Bis-Aminopropyl Diglycol Dimaleate, Fragrance (Parfum), Cetrimonium Chloride, Phenoxyethanol, Glyceryl Stearate, Isopropyl Alcohol, Hydroxyethylcellulose, Hydroxypropyl Guar, Sodium Stearoyl Lactylate, Hydroxypropyl Cyclodextrin, Hexyl Cinnamal, Limonene, Citral, Hydrolyzed Vegetable Protein Pg-Propyl Silanetriol, Disodium EDTA, Linalool, Citronellol, Iodopropynyl Butylcarbamate, Hydroxycitronellal, Etidronic Acid, Tocopherol, Geraniol, Potassium Sorbate, Helianthus Annuus (Sunflower) Seed Oil, Phytantriol, Sodium Benzoate, Pseudozyma Epicola/Camellia Sinensis Seed Oil Ferment Extract Filtrate, Tocopheryl Acetate, Vitis Vinifera (Grape) Seed Oil

Guru Score

85%

Yay

5 experts · Moderate agreement

5Gurus

5Yay

0Mixed

0Nay

What they liked

Leave-in conditioner texture
One pump lasts months
Helps strengthen bleached or colored hair

What they flagged

Nothing. None of the experts who reviewed it raised a problem.

What the gurus are saying

This leave-in serum strengthens hair and helps resist split ends and damage between trims, earning particularly strong praise from people with bleached or heavily colored hair. A single pump applied to damp hair before blow-drying covers what's needed, and the concentrated formula is potent enough that one 100ml bottle lasts close to a year for most users.

Synthesized from 5 expert reviews · most recent take February 2026

Type

Liquid

Key actives

Vitamin E

Formula notes

Contains fragranceContains drying alcohol

Where to buy

Amazon → Google → iHerb →

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What the gurus are saying.

Every take we've logged from this product's reviews across YouTube. Click any row to watch the moment they said it.

All takes Yay takes Nay takes Mixed takes Hide sponsored

Dr. Jenny Liu

322k subs

✓Yay

"I did take a break from Olaplex for a while, mostly because I was so about K18, and then recently reintroduced their hair mask and their leave-in, I think it's number six treatment. It's almost like a leave-in conditioner, and I've absolutely been loving it."

No BS Beauty

89k subs

✓Yay

"I've had good luck with [Olaplex] in the past uh I really enjoy"

AliceintheRabbitHole

59k subs

✓Yay

"I love Olaplex, it works really well for me. I have bleached my hair a lot and Olaplex works for me. I know it's a controversial brand, but it works for me."

Dr. Somji Skin

359k subs

✓Yay

"What I like to do at night is use this Olaplex No. 6. This is essentially going to help colored hairs. It's got a lot of essential ingredients for not only hair health but also scalp health as well."

Kelly Driscoll

90k subs

✓Yay

"I used the Olaplex No. 6 Bond Smoother on my damp hair as a strengthening treatment, and look at how much shine my hair has."

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All 5 takes from Kelly Driscoll

5 Star Skincare Empties! ⭐⭐⭐⭐⭐

"I don't think I've ever named Olaplex a favorite, but it is really a favorite. This is a five out of five hair care product for me. I think it really helps to strengthen my hair, helps to keep it in really good shape. I think it helps resist some split ends and damage on my hair in between trims. I really like it. It's about $30, you get 100 ml, this bottle lasts forever for me. I don't wash my hair a ton, so this actually usually lasts me close to a year, honestly. So pretty decent investment, I think. Personally, just use one pump."

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"I'm finishing off with the Olaplex No. 6 Bond Smoother."

Filming Routine | Do Skincare, Hair and Makeup With Me!

"I used the Olaplex No. 6 Bond Smoother on my damp hair as a strengthening treatment, and look at how much shine my hair has."

My Go-To Hair Care Routine

"This is the Olaplex No. 6 Bond Smoother serum and I do this every time that I wash my hair when it is damp I will apply this to my hair. This is another product that helps to strengthen the hair it has like the bonding right, and so it is really good for color treated hair. I do color treat my hair like every six weeks, so my hair is in a very good healthy state but having something like this in my routine just like regularly is really important for just maintaining some health. I do about a pump, it's got this more like a cream gel texture again not too heavy, it's not like an oil based type of hair product at all. I mostly run the majority of the product through the bottom half of my hair first and then when my hands have just a little bit of product that's when I'll start to do the top."

Slow Morning, Late Summer Skincare Routine

"I use a pump of the Olaplex No. 6 Bond Smoother serum for my hair before I blow dry it"

What the evidence says.

Independent of what the gurus think, this is what the published research supports about the main active ingredients here.

Vitamin E

Vitamin E is an antioxidant, and it is often in a formula to keep the other ingredients stable rather than as the active itself. It pairs well with vitamin C, though on its own the evidence for visible change is limited.

Source: NIH, National Library of Medicine

Frequently asked.

What is Olaplex No. 6 Bond Smoother?

A leave-in serum designed to strengthen hair and protect against split ends and damage.

Is Olaplex No. 6 Bond Smoother worth it?

Yes. All 5 gurus who reviewed it give it their stamp of approval, for a Guru Score of 85%.

What is Olaplex No. 6 Bond Smoother's Guru Score?

Olaplex No. 6 Bond Smoother holds a Guru Score of 85%. That is our read on how warmly the experts talk about it, based on the verdicts of 5 expert reviewers we have collected.