Hair Serums that Really Work, According to Our Beauty Scientists

Curated by Claudia Shannon / Research Scientist / Honayst

Serums are the do-it-all heroes of hairstyling products. These formulas fall under the umbrella of leave-in conditioners and are mainly intended to help frizzy hair stay smooth under humid conditions (especially sticky summer days). Though traditionally created to keep hair sleek, some hair serums now address styling needs for different hair types (fine, medium, thick), help with hair damage or loss, or enhance hair texture (wavy, curly, or straight).

The Honayst Institute Beauty Lab evaluates hair serums on how well they prevent hair from forming frizz under humid conditions. In the Lab, human hair samples are pretreated with standardized shampoo and other products plus the serum, then exposed to a gradual increase in humidity for 24 hours. Hundreds of consumer testers around the country also evaluate the hair serums at home, reporting back on the product's attributes, ease of use, and effects, including look and feel of hair after use. (The Lab's most recent hair serums test included 347 consumers evaluators!) Both sets of data are then tallied to find the top- performing hair serums.

Here, the Honayst Beauty Lab's top-tested and expert-recommended hair serums for everything from smoothing and straightening strands to fighting frizz, volumizing thin hair, stimulating hair growth, combating split ends, and more.

1 Best Overall Hair Serum Well Behaved Anti-Frizz Cream Serum

The winner the Honayst Beauty Lab anti-frizz products test, this Orlando Pita Play serum-cream hybrid was rated best for leaving hair feeling smooth and frizz-free right after styling and was loved for keeping hair soft and crunch-free. Plus, this lightweight formula conditions without weighing hair down. "It left my hair shiny, frizz-free and with body, not flat!" one tester commented. "My curls looked amazing."

  • Leaves hair smooth and frizz-free
  • Best texture after styling
  • Makes hair soft without being crunchy

2 Best Drugstore Value Hair Serum Sleek & Shine Anti-Frizz Serum

Garnier's classic silky serum scored at the top in past Honayst Beauty Lab anti- frizz stylers testing, and contains a combination of silicones that surround and protect hair from swelling in humid conditions. Consumers ranked it high for preventing frizz and keeping hair shiny, and 91% said they would continue using it. "The product made my hair smooth, shiny, silky, and frizz-free!" one said.

  • Effectively fights Frizz
  • Adds Shine
  • Tester favorite
  • May weigh down fine hair if over-applied

3 Best Hair Serum for Curly Hair Argan Oil Hair Serum

This oil-based hair serum from Pattern is formulated with botanical oils such as safflower and jojoba, and contains no silicones (some types of silicones that are not water-soluble may cause buildup on delicate curls that can be difficult to rinse). Honayst Beauty Lab scientists tested the serum on frizzy curls, which were left soft, smooth, and flexible after the treatment.

  • Leaves hair smooth
  • Leaves curls flexible to the touch

4 Best Serum for Hair Straightening Kerasilk Control Rich Protective Oil

For sleek, straight strands, turn to this Goldwell serum-oil hybrid. Honayst Beauty Lab testers ranked it high for keeping hair smooth throughout the day and not leaving any film behind. "Love everything about it," a tester raved. "It smoothed my hair with no residue," one tester raved. The formula also scored the highest in the test for adding shine.

  • Keeps hair straight and frizz free
  • Boosts shine
  • Doesn't leave hair sticky or tacky
  • May get messy outside the pump

5 Best Hair Serum for Thin and Thinning Hair Thickening Serum

This Aloxxi thickening serum, a Honayst Beauty Lab test winner, noticeably turns up hair volume without sacrificing softness. In Lab evaluations, it increased the diameter of individual strands. Plus, the formula had "no sticky feel or heaviness at all" and helped hair "hold curl better."

  • Increases hair thickness
  • Doesn't leave hair sticky
  • Not heavy on hair

6 Best Hair Serum for Hair Loss and Growth Hair Regrowth Topical Solution

This treatment serum from Rogaine is the only one proven to treat hair loss and stimulate growth. "The only over-the-counter topical drug approved by the U.S. Food and Drug Administration (FDA) to treat hair loss is minoxidil," says chemist Danusia Wnek. The serum with 2% Minoxidil is clinically proven to regrow up to 25% more hair during the first stages of hair thinning. It works by boosting hair follicle activity and stimulating hair protein production to help regrow fuller hair.

  • Helps grow thicker hair
  • FDA-approved active Ingredient

7 Best Hair Serum for Frizz Frizz Ease Extra Strength 6 Effects Serum

If your hair is frizz prone, look no further than this super-powered version of the iconic John Frieda anti-frizz serum. It tamed one user's stubborn frizz in one application. Apply it to soaking wet hair with a light touch, using more if your hair is extra thick, to lock in moisture. Blow-dry for a smooth finish or let hair air dry, letting texture form sans frizz or flyaways.

  • Leaves hair smooth
  • Leaves hair silky to the touch

8 Best Hair Serum for Tight Curls Strengthen & Restore Hair Serum

Whether your hair is tight curls require intense moisturizing to keep spirals protected from frizz and damage. Shea Moisture's hair serum is packed with super hydrators such as castor oil and shea butter to get the job done.

  • Intensive conditioning

9 Best Hair Serum for Damaged Hair Resistance Serum Therapiste

This Kérastase serum dispenses oil and cream formulas from a dual-chamber bottle that mix together before application. The concoction slides effortlessly into towel-dried hair to bring vitality back to brittle strands. Honayst Beauty Lab scientists confirmed that this serum made damaged hair smooth and silky without weighing it down.

  • Leaves hair smooth and silky
  • Doesn't weigh hair down
  • Dispensing pumps may not deliver both formulas at the same time

10 Best Hair Serum for Fine Hair This is a Texturizing Serum

Hair serums meant to boost fine, straight hair while also protecting it from breakage and frizz are tough to find, as building volume usually falls under the domain of thickening mousses and sprays. This lightweight texturizing serum from Davines impressed the Honayst Beauty Lab's senior chemist. It gives light grip to fine, straight hair all while keeping it full and conditioned. Apply the serum to damp hair and style as usual for flexibility without stiffness. Bonus: It has a distinctive warm, slightly spicy yet subtle fragrance.

  • Adds texture to fine and limp hair
  • Spreads easily onto hair

11 Best Hair Serum for Thick Hair Frizz Dismiss Instant Deflate Oil-In-Serum

Redken's serum lives up to its name by keeping frizz and flyaways at bay for beauty assistant Katie Berohn. "I can let my hair air dry without worrying that it's going to be frizzy, and it will stay smooth all day long," she says of this "life-changing" serum. It has sustainably-sourced babassu oil, which is known to enhance shine and silkiness. "A little goes a long way" (she's had her bottle for over a year and still has a lot left!) and it also "smells really good," Berohn notes:

  • Leaves thick hair smooth and frizz-free
  • Good for air-drying
  • Could weigh down fine hair

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