We all want hair that looks and feels like a million bucks, right? Well, folks, it's easier than you think. Incorporating a good hair serum into your routine can really change the game.
There's truly a formula for every hair goal, whether that's growth, extra hydration, or a thicker appearance. I personally fall into the "extra hydration" camp since my hair is incredibly thick and curly, and I can say with confidence that the addition of a moisture-boosting serum really helped the health of my hair.
If you're in the market for a new addition to your haircare routine, you'll definitely want to keep scrolling. I'm sharing a few key serums you should invest in based on your hair goals along with advice from a celebrity hairstylist.
The Best Hair Serums in 2026, at a Glance
- Best Overall: Moroccanoil Mending Infusion Styling Hair Serum
- Best for Fine Hair: R+Co Dallas Biotin Thickening Treatment
- Best for Hair Growth: Act+Acre 2% Stem Cell H2-Grow Complex Scalp Serum
- Best for Frizz: Olaplex No. 9 Bond Protector Nourishing Hair Serum
- Best for Dryness: Bumble and Bumble Hairdresser's Invisible Oil
The Best Hair Serums in 2026
Best Overall: Moroccanoil Mending Infusion Styling Hair Serum
This light yet extremely nourishing hair serum from Moroccanoil nabs the top spot because it's hydrating enough for thicker hair types but light enough for finer ones. Argan oil restores elasticity, smoothness, and manageability, while baobab extract and hydrolyzed quinoa strengthen and further condition the hair.
Pros: Restores hair elasticity, promotes smoothness
Cons: Some say the smell is too strong
Size: 2.5 oz
Key ingredients: Argan oil, boabab extract, hydrolyzed quinoa
Customer review: "I’ve been using this serum every night for a week and I’ve noticed such a big difference in my hair breakage! I dye my hair every 1 to 2 months, so this is a game changer for healthier hair!!"
Best for Fine Hair: R+Co Dallas Biotin Thickening Treatment
Celebrity hairstylist Laurabeth Cabott loves this serum treatment with biotin from R+Co for thinner hair types. "My clients are always raving about how full their hair feels [when they use it]," she says. It's chock-full of hair-strengthening and shine-boosting ingredients like biotin and ginseng root, and quinoa-seed extract and castor oil help repair damaged hair.
Pros: Prevents breakage, adds shine, reduces split ends
Cons: Not ideal for thick hair
Size: 3 oz
Key ingredients: Ginseng root extract, hydrogenated castor oil, quinoa seed extract, rice starch
Customer review: I absolutely love this! Works really well on thinning hair and leaves air dried hair looking so shiny!!
Best for Hair Growth: Act+Acre 2% Stem Cell H2-Grow Complex Scalp Serum
Although several options on this list are great at encouraging healthy hair growth, Act+Acre's formula is our favorite. It also doesn't hurt that it has a near-perfect five-star rating on Sephora's website. It's powered by a Stem Cell H2-Grow Complex that supports hair growth for fuller, thicker, and longer strands. Apple stem cells stimulate hair follicles, and bamboo and pea extracts address premature aging of the hair follicles.
Pros: Reduces itchy scalp, boosts hydration, protects from damage
Cons: Not ideal for sensitive skin
Size: 1 oz
Key ingredients: H2-Grow Complex, hyaluronic acid, bamboo and pea sprout blend
Customer review: "I really like this scalp serum from Act+Acre. I have a super dry scalp that itches and flakes especially in the winter. This makes it feel super hydrated now. Definitely recommend for dry scalp girlies."
Best for Frizz: Olaplex No. 9 Bond Protector Nourishing Hair Serum
If you have a lot of baby hairs that just never want to lie smooth, Olaplex products just might change your life. I use the brand's Bond Maintenance Shampoo and Conditioner ($60), and I can definitely vouch for each's ability to tame frizz—it's truly the best duo I've used in a while. The No. 9 hair serum is equally as good at nourishing hair while reducing things like static and frizz. Additionally, it helps repair broken bonds for stronger hair, blocks daily pollutants, and can act as a heat protectant.
Pros: Promotes stronger hair, protects against free radicals
Cons: Not ideal for thin hair
Size: 3 oz
Key ingredients: Bis-aminopropyl diglycol dimaleate, red algea extract
Customer review: "I started using this product after cutting my hair. I have noticed fewer split ends and fairy knots in my hair. I have been able to grow my hair longer because there are fewer split ends and less breakage."
Best for Dryness: Bumble and Bumble Hairdresser's Invisible Oil
If your hair tends to dry out easily, try an oil-rich formula like this one from Bumble and Bumble. It's completely weightless and won't leave hair greasy, but it does provide a heck of a lot of moisture with coconut, argan, macadamia-seed, sweet almond, and grapeseed oils.
Pros: Adds shine, protects against breakage, softens
Cons: Can feel greasy to some
Size: 3.4 oz
Key ingredients: Coconut oil, argan oil, grape seed oil, macadamia oil, sweet almond oil, safflower seed oil
Customer review: "I have dry relaxed hair. I have been on the hunt to find a good moisturizing hair serum that works well on my fine to medium hair. This works amazing."
Best for Thick Hair: Mizani 25 Miracle Nourishing Oil
Having thick hair can be a struggle—take it from someone who knows. You need something hydrating, especially if you also have curls, but the formula can't be too much, or it will weigh down your already thick mane. Mizani's Nourishing Hair Oil definitely solves that problem. It contains a blend of coconut, jojoba, and sunflower oils to strengthen, moisturize, and add softness to the hair without making it greasy.
Pros: Reduces frizz and adds shine
Cons: Some say the scent is too strong
Size: 4.2 oz
Key ingredients: Jojoba oil, coconut oil, sunflower seed oil
Customer review: "Lovely! My hair looks so healthy and feels so smooth. I usually have major frizz issues, and this greatly improved that"
Best for Curly Hair: Davines This Is a Curl Building Serum
My stylist recommended this curl serum to me a few years ago, and I never looked back. First, it smells like a dream, so I always look forward to putting it on. Second, it adds so much softness and definition to curls without making them crunchy or causing buildup on my scalp. It's also flexible and hydrates beautifully. Do yourself a favor and give it a go. I don't think you'll regret it.
Pros: Adds shine and definition
Cons: Some users find it sticky
Size: 8.45 oz
Key ingredients: Glycerin, vitamin B5
Customer review: "There’s no better product than this one for my curls! It smells delicious. You don’t need to put too much product and it works just fine! Helps with the frizz for humid places too."
Best for Natural Hair: Adwoa Beauty Baomint Protect + Shine Oil Blend
Like curls, natural hair textures tend to get dry easily and need a lot of extra moisture. This Adwoa offering is more of an oil blend than a serum, but it supports a healthy scalp, moisturizes deeply, and helps prevent future hair loss with a blend of antioxidant-rich oils.
Pros: Prevents hair loss, moisturizes, supports scalp health
Cons: Some say the smell is too strong
Size: 7.2 oz
Key ingredients: Fractionated coconut oil, pomegranate seed oil, grapeseed oil
Customer review: "I love how this product seals in moisture. It’s super hydrating but not sticky like other serums and oils. I love using it on my scalp with my braids because it doesn’t cause build up. It also works great on my natural hair."
Best Drugstore: OGX Nourishing + Coconut Milk Anti-Breakage Serum
Strand breakage can be extremely frustrating, but with the right tools in your arsenal, it can be a thing of the past. This OGX serum helps strengthen, repair, and hydrate hair with coconut oil and coconut milk. Whipped egg white protein in the formula also helps promote smoother, shinier hair.
Pros: Adds shine, smells good, strengthens hair
Cons: May be too heavy for fine hair
Size: 4 oz
Key ingredients: Coconut oil, coconut milk, whipped egg white protein
Customer review: "This is one of the best affordable hair oils. It applies easily, and it's not too thick or heavy on my fine hair. It smells amazing! Helps my hair with strength and prevents breakage."
What to Look for in a Hair Serum
The best hair serums offer a variety of benefits, but you'll want to pick one based on your current hair goals. If you want to promote growth, Cabott has a bit of advice. "There are several key ingredients that go into [hair growth–promoting] products—the main ones being biotin, peppermint, and keratin," she says. Of the three, biotin is the most common ingredient you'll see in a formula that's meant to promote strand growth.
Those with dry hair who need extra hydration may want to go a different route. "If you're lacking moisture, look for something with coconut, aloe, or vitamins such as B5," Cabott adds. Thinning or fine hair types should invest in a thickening serum. These types of serums plump the hair follicle to give strands a fuller, more voluminous appearance. Those with thick hair will want to look for something lightweight and hydrating that won't weigh the hair down, and curly, coily, and natural hair types will want formulas that lock in extra hydration since they tend to dry out easier.
How We Chose
As with all of our buying guides at Who What Wear, we compile our edits based on original testing and expert recommendations. To find the best hair serums for this roundup, we leaned heavily on expert insight and our knowledge as beauty experts. We also considered several factors, including key ingredients and size. We're aware of how important these factors are for a wide range of needs and preferences, so we made sure to list out all the helpful details. Of course, customer reviews were also kept in mind when creating this list.
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Since 2006, Who What Wear has been a digital fashion, beauty, and lifestyle publication and community where people can discover the latest brands, trends, and must-have products to help define and evolve their personal style. Think of Who What Wear as your most trusted style and shopping resource.
This story was published at an earlier date and has since been updated.