Editor's TipEditor's Tip

For best results, condition with Number 4™ Lumiere d’hiver Reconstructing Masque.

Number 4 Hair Care

Birchbox Breakdown

There was a time when we were a bit skeptical about hair oils—the last thing we wanted was a greasy, weighed down ’do. These days, however, we can't imagine a haircare routine without it. This strand-saving elixir gives drab, dull hair a coveted movie star shine (plus a whole host of reparative benefits). Our oil-free days are officially over.

How to Use

Distribute one to two pumps through damp hair, then style as usual. For added radiance, apply one pump of product to dry hair.

Cyclopentasiloxane,C13-14 Isoparaffin,Dimethicone,Dimethiconol,Phenyl Trimethicone,Perfluorononyl Dimethicone,Fragrance (Parfum),Benzyl Salicylate,Butylphenyl Methylpropional,Linalool,Hydroxyisohexyl 3- Cyclohexene Carboxaldehyde,Ethylhexyl Methoxycinnamate,Argania Spinosa Kernel Oil,Helianthus Annuus (Sunflower) Seed Oil,Glycerin,Sodium Ascorbyl Phosphate,Hydrolyzed Soy Protein,Macrocystis Pyrifera Extract,Ribes Grossularia Fruit Extract,Ribes Nigrum (Black Currant) Leaf Extract,Arctium Lappa Root Extract,Avena Sativa (Oat) Kernel Extract,Camellia Sinensis Leaf Extract,Chondrus Crispus (Carrageenan) Extract,Cymbopogon Schoenanthus Extract,Euterpe Oleracea Fruit Extract,Garcinia Mangostana Peel Extract,Hibiscus Sabdariffa Flower Extract,Hydrastis Canadensis (Golden Seal) Root Extract,Ilex Paraguariensis Leaf Extract

More for You!

Product Reviews & Sample Feedback

8,840 Reviews
4.2 out of 5 stars
5 Star
4093
4 Star
3202
3 Star
1193
2 Star
252
1 Star
100
my profile
people who
purchased
sampled
Hair type
Thick
Fine
Straight
Wavy
Curly
Frizzy
Kinky
Dry
Normal
Oily
Hair color
Brown
Blonde
Black
White or gray
Red
Other
Age
17 & under
18-24
25-34
35-44
45-54
55 & over
Apply

Most Helpful Customer Reviews

Be careful
Sampled

Use very sparingly and in small amounts or else your hair will look very greasy

4
Was this review helpful to you? Yes | No 34 of 34 found this review helpful. Was this review helpful to you? Yes | No
Weightless Shine

Love it! I have very very fine, long, color treated hair, so I need a little extra strength/moisture and shine without weighing down my hair any more than usual. I've tried all sorts of serums and glossing creams and stuff in the past with usually average results at best - either I'm not getting the shine results I want or I look like a wet dog, all weighed down with goop. Bought a bottle of this on a whim since I've been such a fan of the other Number 4 products I've sampled, and I'm SO glad I did. This is it.

After a couple of uses, hair is exceptionally shiny and looks healthier than usual. However, my hair is NOT weighed down at all. If anything, it's moving more than usual. And it feels super soft. I'm hoping continued use does improve the health of my hair, but even if not I'd keep using this stuff based on looks alone.

5
Was this review helpful to you? Yes | No 40 of 42 found this review helpful. Was this review helpful to you? Yes | No
A little goes a long way
Sampled

I have very thick, coarse, currly hair. Even small amounts from the sample size smoothed over the top layer of my hair really made me feel like I was getting an extra layer of softening and protection!

4
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Pretty good
Sampled

I really like this product it makes my hair soft and shiny and smells amazing.

4
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
A little bit goes a long way...but so amazing!
Sampled

I absolutely love this stuff. During the winter months, when I brush out my hair, I literally look like I just took a balloon and rubbed it all over my head to make my hair stand on end. With about 2 drops of this amazing hair oil, I can tame my crazy locks and it doesn't weigh my hair down or look greasy. The smell is a big plus too!

5
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Hair oil
SampledPurchased

Love this product and pretty much anything number 4 makes my hair look smooth and neat when I have a lot of breakage on my ends

5
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Great product
Sampled

I was a bit skeptical about this product being greasy but to my surprise it wasn't. My hair is thin and this didn't weigh it down or look greasy at all.

5
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Little amount works great
Sampled

I put just a little amount on my wet hair and then after I blow dry and my hair comes out looking great. Love the smell of the product too.

4
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Smells amazing
Sampled

Not sure how well this actually works, but I now use it every morning simply because it smells so good and since it requires such a small amount it lasts forever!

3
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No
Secret weapon for hair
Sampled

This serum is the perfect product to use for hair styling! It never makes my hair greasy and keeps it looking fresh and perfectly styled all day, just by using the smallest amount!

5
Was this review helpful to you? Yes | No   Was this review helpful to you? Yes | No