Truth be told, hair serums are the only styling product I use regularly. My hair is very thick, very fine, but also incredibly fine, which means anything heavy—hair creams, oils, lots of leave-ins—can take it from freshly washed to flat and matted in about thirty seconds. Hair serums, on the other hand, give me benefits without that heavy feeling. A drop or two on the edges adds shine, smoothness, and keeps it looking and feeling healthy.
That being said, hair serum is no longer a specific product. Others are about glazing and polishing—the kind that smooths the edges after air-blasting when you want a glass-like finish. Others focus on strengthening damaged strands or conditioning frizz throughout the day. And my latest favorites are designed to work all night, helping to support hair health while you sleep.
As celebrity hairstylist Glen Operazna explains, the right nighttime formula can quietly do the heavy lifting: in the morning, hair should feel “softer, healthier, smoother, and more resilient, with improved shine and manageability.” He also points out that many of these formulas now include heat protection, which helps protect strands from the styling damage that often follows the next day.
Below are the hair serums I reach for most often—and the different roles they play in my routine.
Night Shift
My favorite type of hair serum is formulated to do its best work while you sleep. These overnight formulas often rely on repairing oils, peptides, or bond-building ingredients that help support damaged strands. I like to apply them from mid-lengths to ends after my nightly shower and just before bed. The formula absorbs overnight—in the morning, my hair feels noticeably softer and ready for work the next day.
Kérastase
Chronologist Overnight Youth Serum
This is the brand new serum from Kérastase that I have been patiently waiting for. I’m already a fan of the Nutritive 8H Magic Night Hair Serum, so I had high expectations. When I first used it, I woke up with smooth, soft hair. It also appears thicker, thanks to its ability to increase the density of each hair cuticle. It’s also perfect for dry, mature hair, so you can trust it to deliver maximum moisture and shine.
R+Co Bleu
Night repair serum Sleeping Masque
Once you get past the price point, this luxurious hair mask serum does wonders for your hair. Think of this as a really rich night face cream that locks in ingredients that hydrate skin for super smooth skin—the Sleep Masque does the same thing, except for your hair.
Glass-Hair Finish
No one can deny the power of super shiny, super shiny hair. It looks good and it’s expensive. These serums are all about polishing, smoothing the cuticle so that light can reveal the hair evenly.
JVN
Renew Rapid Repair Bond Gloss
This serum is a little different than the others as it is an in-shower treatment that is used after shampooing and conditioning. Once installed, leave it on for 60 seconds, then rinse. Treats split ends and smoothes the cuticle.
A dry bar
Liquid Glass High-Gloss Finishing Hair Serum
Anything with the name “Liquid Glass” I pay attention to, and apparently, many others, as it sells well and has glowing reviews. Powered by a nourishing formula, this finishing serum infuses hair with an abundance of hyaluronic acid for continued hydration.
Frizz Fighters
Humidity, heat styling, and sweat all leave my hair in a state that is often difficult to repair. That’s why I prevent it from happening in the first place with a hair serum that smoothes and seals the cuticle. This helps control frizz and prevents moisture from entering the hair shaft, preventing chick.
RŌZ
Milk Hydrating Leave-In Conditioner Hair Serum
The MC team is passionate about all RŌZ hair care products. This milk serum works on all hair types, making it a great universal product for banishing frizz and flyaways thanks to its hydrating power. It also acts as a great detangler, helping to prevent breakage that leads to frizz.
Kenra
A serum for shiny shiny hair
Smooth hair equals less frizz, and this leave-in shine provides moisture resistance for hours on end. I apply this before I heat my hair, and it helps protect it from further damage. And it smells great, courtesy of the fruit and orange scent.
Damage Control
If your hair has been through bleach, color, hot tools, all of the above-these formulas help to strengthen weak strands. Many contain bond-supporting technology, proteins, or strengthening oils that temporarily fill in weak spots along the hair shaft, making hair feel stronger and look flawless.
Olaplex
Number 9 Bond Protector Hair Serum
I can’t name a bond repair treatment without first offering Olaplex, that is, the brand that has made repairing damaged hair their motto. No. 9 Bond Protector is the best in string strengthening and the entire line—which, spoiler, is the best.
Pureology
Power Cure Dream Healer Serum
I am in a committed relationship with Pureology shampoos and conditioners, and I recently welcomed this serum into the family. The formulation relies on a combination of acids that strengthen weak bonds, reduce future breakage, and visibly smooth cracks in the hair cuticle.
The scalp first
Hair health really starts at the scalp, which is why scalp-focused serums have become such a big category. These formulas often include ingredients such as peptides, niacinamide, caffeine, or botanical extracts that help support a balanced scalp environment, conducive to hair growth.
Vegamour
Gro Hair Serum for Hair Reduction
Senior Beauty Editor Samantha Holender recommends this serum as one of the main products responsible for fuller hair in her growth journey. Caffeine stimulates the scalp while turmeric increases the appearance of the hair, and biotin and peptides suddenly penetrate to strengthen the strands.
Nécessaire
Rosemary Serum
FYI, rosemary has been proven to have the same effects as minoxidil, the active ingredient in Rogaine for hair loss. This serum is one of the most natural of the big name brands out there, and testers have seen promising results.
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Meet the Experts
Glen Oropeza, also known as Glen Coco, is a celebrity hairstylist and social media influencer. Her clients include Sydney Sweeney, Kourtney Kardashian, and Megan Fox. Oropeza started her career in Baltimore, then moved to New York to help with fashion events and brands. He eventually settled in Los Angeles, where he worked as a colorist at a West Hollywood salon. Oropeza’s art and skills have attracted the attention of Hollywood’s elite.