You can think of hair serum as a protective shield for your hair. Sure, you probably use a conditioner on your hair, but immediately after stepping out of the shower you might blast it with a hair dryer, sizzle it with a curling wand, or expose it to a day in the sun and salt water. That’s where a hair serum can come into play; not only can hair serum safeguard your locks against all of those elements, but invest in a good one and it’ll give your hair a boost of hydration too.
“It is necessary to protect your hair the way you would protect your face with moisturizer,” says Kimberly Gueldner, Amy Schumer’s personal hairstylist. “You would rarely leave the house without moisturizer on your face, and the same philosophy should be applied to your hair.”
Byrdie Researched & Approved
Olaplex No 9 Bond Protector Nourishing Hair Serum is our best overall pick because it forms a shield against pollution for 48 hours, protects against heat damage and adds shine. For a more budget-friendly pick, Garnier Fructis Sleek & Shine can provide an anti-frizz finish for a fraction of the price.
To find the best hair serums on the market, we conducted hours of research—evaluating each option based on their active ingredients and benefits. We also looked for any extra features, like if they could work on all hair types or had a clean ingredient list. After consulting experts and considering dozens of formulas, we landed on these top-rated picks.
Olaplex No. 9 Bond Protector Nourishing Hair Serum
Shields from pollution for 48 hours
Anti-tangle and anti-static
Protects against heat damage
Olaplex’s No.9 serum tops our list because it does it all—hydrates, protects, adds shine—for all hair types. Shield your hair from everyday damage by working a little bit of the serum (a little goes a long way, trust us) through your damp or dry hair, then bask in its lightweight silkiness. The silicone-free formula will leave your hair shiny, soft, and making you wonder where this serum has been your whole life.
Reviewers loved that they got the same results whether they air-dried or heat styled, and that it made their hair look healthy (even when damaged) and silky. They also noted that it tamed their flyaways all day.
Price at time of publish: $30
Key Ingredients: Red algae extract, bond building technology | Hair Type: All | Size: 3 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Garnier Fructis Sleek & Shine Anti-Frizz Serum
Can be used on damp or dry hair
Can make hair look greasy if not used sparingly
Garnier’s Sleek & Shine serum is a prime example that you don’t have to compromise your budget for a good hair day. Whether you have curly, straight, or dry hair, its blend of apricot and argan oils will provide you with a smooth finish—all for under $6.
Price at time of publish: $6
Key Ingredient: Argan oil, apricot oil | Hair Type: All | Size: 5.1 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
MAY11 Revitalizing Hair Oil
Hydrates dry hair
Rehabs chemically damaged hair
Not recommended for blondes
There’s no denying that MAY11’s Revitalizing Hair Oil is an investment, but there’s also no denying how effectively it revives dull hair. NYC-based hairstylist Annie Rush, who particularly loves this oil for anyone with coarse, curly hair, agrees: “A little goes a long way, but a few extra pumps and a thorough brush-through can act like a pre-shampoo treatment for those ‘everyday or longer’ shampoo washers,” she says.
“MAY11 has a rare natural ingredient called neroli oil which deeply penetrates the hair cuticle for dry or damaged hair therapy,” she adds. Bonus: This serum is packed with essential oils, so this will quickly take the place of your favorite perfume.
Price at time of publish: $86
Key Ingredients: Neroli oil, Jamaican black castor oil, hemp seed oil | Hair Type: All | Size: 2 oz. | Cruelty Free: No | Byrdie Clean: Yes
Best for Hair Growth
The Ordinary Multi-Peptide Serum for Hair Density
Helps hair look fuller and thicker
Can be used on all hair types and textures
Must be used continuously for best results
Show of hands: Who wants thicker, fuller, denser, healthier hair? (That’s what we thought.) That’s where The Ordinary’s serum comes to the rescue. Whether you have loss of hair from alopecia or a pregnancy or have patchy eyebrows from overplucking—thanks, early 2000s—this serum will encourage regrowth. Simply apply it to your scalp before bed each night, then wake up to fuller hair in just a few months.
Price at time of publish: $26
Key Ingredients: Redensyl, procapyl, baicapil | Hair Type: All | Size: 2 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Best for Curly Hair
Curls Blueberry Bliss Hair Growth Oil
Nourishes all curly hairstyles
Stimulates hair growth
Strong scent isn't for everyone
Thick, curly, coarse-haired folks, this serum is for you. With the intention to celebrate your natural texture, Curls formulated this serum using blueberry extract, which encourages hair growth while also repairing damage and preventing further breakage. Whether you have waves, curls, or coils, apply this as a pre-shampoo or a finisher, then enjoy the feel of your newly hydrated hair.
Price at time of publish: $12
Key Ingredients: Blueberry extract, argan oil, castor oil | Hair Type: Curly | Size: 4 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Best for Natural Hair
Laaayed Nourishing & Soothing Serum
Targets hair and scalp dryness
Can be used on damp or dry hair
Blueberry scent may not be for everyone
Leave it to the founder of PuffCuff, the popular hair clamp for thick, curly hair, to create a hair serum for—you guessed it—thick, curly hair. Whether you wear your natural hair in twists, braids, or curls of any kind, Laaayed’s serum will seal in moisture, both in your hair and on your scalp. Use it on wet hair after detangling to define your curls, or add it to dry hair to hydrate.
Price at time of publish: $18
Key Ingredients: Avocado oil, jojoba oil, rice bran oil | Hair Type: Natural | Size: 4 oz. | Cruelty Free: N/A | Byrdie Clean: Yes
Alterna Caviar Anti-Aging Restructuring Bond Repair 3-In-1 Sealing Serum
Seals damaged ends
Reduces blow dry time
Reviewers note it can have a sticky texture
For the ultimate multitasking serum, add a bottle of this Alterna formula to your cart. It repairs damaged hair, adds softness and shine, and protects against heat styling—all in one tiny bottle.
Gueldner is a fan too. “This highly versatile serum makes it a good option for all hair types. The caviar extract helps seal hair cuticles to protect damaged hair,” she says. “I love that it is lightweight and is a great product to layer over. It is a great base product to layer heavier products over if you have thick hair, and it can also be mixed with your deep conditioner to help seal the cuticle and repair the hair.”
Price at time of publish: $38
Key Ingredients: Caviar extract, phytantriol | Hair Type: All | Size: 1.7 oz. | Cruelty Free: No | Byrdie Clean: Yes
Best for Dry Ends
Sachajuan Shine Serum
Seals split ends
Prevents further hair damage
Adds serious shine
Small, but mighty. That’s the best way to describe this petite bottle of Sachajuan serum, which guarantees to give your hair a protective, shiny finish. Just a pump or two of this lightweight serum, which conveniently fits into your TSA-friendly liquids bag, will repair your damaged ends. It quickly absorbs into your locks, so it doesn’t leave behind residue or weigh down your hair either.
Price at time of publish: $36
Key Ingredients: Geraniol, limonene | Hair Type: All | Size: 1.01 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Pai-Shau Biphasic Infusion
Provides serious hydration
Has a citrusy, floral scent
Overuse can cause buildup
“Most serums on the market are purely for shine and polish,” says professional hairstylist Marshall Lin. Pai-Shau’s Biphasic Infusion also provides hydration for the hair, which is what sets it apart. “The ingredients in this serum offer both a treatment as well as the cosmetic benefits of shine.”
The best part of Biphasic Infusion, says Lin, is that it’s oil-free, which is rare for a hair serum. Instead, this formula contains a mix of five steeped teas that each nourish your hair and scalp. “It's genius, actually,” Lin says. Use this on wet hair for a treatment and then again on dry hair once styled for shine. “Since it's oil-free, you can keep applying it and reapplying without having the oily look or having your hair look weighed-down,” he says.
Price at time of publish: $24
Key Ingredients: Pai-Shau's signature tea complex | Hair Type: All | Size: 1 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Stephen Knoll Hydrating Serum Mist
Restores moisture in hair
Convenient spray bottle
Too bulky to travel with
While most hair serums involve working the formula through your palms first, this serum-mist hybrid keeps your hands clean and your hair hydrated with just a few spritzes. Use it as a leave-in protective treatment to counter the effects of heat styling and pollution, or give your hair a midday mist to calm any flyaways. No matter when or how you use it, this mist is a lightweight solution to instantly revitalize your hair.
Price at time of publish: $35
Key Ingredients: Hydrolyzed collagen, safflower seed oil, fructose | Hair Type: All, especially colored hair | Size: 5 oz. | Cruelty Free: | Byrdie Clean: Yes
Best Lightweight Serum
Milbon Hairserum Oil
Two formula options, one for fine and medium hair and another for coarse
Smooths damaged ends and flyaways
May have to reapply throughout the day to keep flyaways down
For a barely-there serum, Rush reaches for Milbon’s oil. “I use this product on every client (blondes included) to finish styling their ends, flyaways, or add shine to any updo,” she says. “This can help as a quick daily fixer upper for damaged or dry ends or at-home lackluster styling.” Made with jojoba oil and shea butter, it leaves a lightweight finish that easily gets washed away with each shampoo without leaving behind any product buildup.
Price at time of publish: $35
Key Ingredients: Jojoba oil, shea butter, soybean oil | Hair Type: All | Size: 4.1 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Best Sustainable Packaging
Hairstory Hair Oil
Sent in a reusable glass bottle with recyclable refills
Treats dry and dull hair
Suitable for all hair types and textures
Can make your hair look greasy if overused
As much as we adore trying new beauty products, we don’t exactly love all of the packaging waste that goes hand-in-hand with it. That’s why we especially love Hairstory’s approach to packaging with this hair serum, which arrives in a reusable glass bottle with recyclable refills. The fact that it repairs damaged hair and smooths frizz too? All the better.
Price at time of publish: $35
Key Ingredients: Argan oil, evening primrose oil, jojoba oil | Hair Types: All | Size: 2 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Goldie Locks Signature Serum
Receive two complimentary hair care samples with every purchase
Helps against humidity
Comes in a heavy glass bottle
When traveling, every centimeter in your TSA-approved liquid bag is prime real estate. But that doesn’t mean your hair should have to endure copious amounts of sunshine, chlorine, humidity, or sea salt without the help of a serum. Nab one of these travel-sized Goldie Locks serums and your hair will be shiny and frizz-free, no matter where you’re vacationing. Plus, with its secure cap you can feel confident it won’t leak all over your other liquids. (The worst.)
Price at time of publish: $32
Key Ingredients: Rose water, vanilla bean, white truffle | Hair Types: All | Size: 1.7 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Best Clean Formula
Ceremonia Oil Mist con Aloe Vera Nourishing Hair Elixir
Nourishes damaged hair
Reviewers note that packaging could be better
This nourishing hair serum is not only completely vegan and made with natural ingredients (aloe vera, chia seed oil, and more)—it's also able to hydrate, add shine, and tame frizz for all hair types. Since it has an oil-mist hybrid formula, it only takes a few spritzes to take your hair from damaged and dull to looking healthy and glossy.
Price at time of publish: $26
Key Ingredients: Aloe vera, chia seed oil, coconut oil | Hair Types: All | Size: 2 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Best for Scalp
Nécessaire The Scalp Serum
Proven to show results
Takes time to show noticeable growth
The health of our hair is important, but our scalp health is arguably just as—or maybe even more—important. This serum is able to hydrate with hyaluronic acid and strengthen the scalp with niacinamide. A healthy scalp leads to thicker, healthier hair, and it also includes a peptide blend that's been proven to accelerate hair growth.
Price at time of publish: $58
Key Ingredients: Biomimetic peptide blend, hyaluronic acid, niacinamide | Hair Types: All | Size: 2 oz. | Cruelty Free: Yes | Byrdie Clean: Yes
Our top overall pick in hair serums is the Olaplex No 9 Bond Protector because it protects the hair from environmental stressors and heat while making the hair silky and shiny. We also love the more affordable Garnier Fructis Sleek & Shine, which tames frizz and keeps hair smooth in humid conditions.
Meet the Expert
What to Look For in a Hair Serum
When scanning the ingredients list, Gueldner notes that one ingredient in particular shouldn’t be there: alcohol. “Alcohol is extremely drying on the hair and can often continue to damage hair that might be compromised,” she says. “A product with an oil base is best for restoring moisture and elasticity.”
Frequency of Use
In general, lightweight hair serums can be used daily to protect your locks against the elements and heat styling. For thicker, oilier products, aim to treat your hair with them once or twice a week. Read the directions to determine the recommended frequency of use, then experiment with it, varying the amount of product and frequency you use it depending on your hair’s needs.
What is hair serum used for?
“It coats the hair and protects it from the elements and heat styling,” says Gueldner. The benefits don’t end there though. A hair serum can nourish and hydrate your hair in addition to controlling frizz and locking in split ends. Depending on your hair type and goals, use it as a base product or as a finishing product, alone or under a heavier cream or oil.
“Hair always needs hydration,” says Lin. “It works anytime, but for a clear result, apply anytime your hair feels dehydrated, which can be before and after you spend a day under the sun, experience a weather change, or are going through some health issues that may be taking a toll on your hair.”
Can you use a face serum in your hair?
Oftentimes, yes. Since hair and skincare serums are made with many of the same ingredients, a facial serum can generally be used interchangeably with a hair serum.
Why Trust Byrdie
Seasoned commerce writer Megan McCarty has been covering the best of the best of fashion and design for over 15 years. Her work can be seen in InStyle, Domino, Architectural Digest, Bustle, and more. Her long locks would be lifeless without the help of her favorite serums, several of which made this list.
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Madaan P, Sikka P, Malik DS. Cosmeceutical Aptitudes of Niacinamide: A Review. Recent Adv Antiinfect Drug Discov. 2021;16(3):196-208. doi: 10.2174/2772434416666211129105629. PMID: 34844552.