Hair growth is personal, results depend on the cause of your hair loss, and most importantly, patience is key. For that reason, I worked with wider Glamour team members and expert contributors to test each hair serum over several weeks and months. You'll find videos, before and after photographs by myself and Beauty Editor Maisie Bovingdon below.
We reviewed the full ingredients list of every hair serum before we start testing, before considering how each hair serum feels on the scalp (is it sticky, greasy or soothing?), how easy it is to use, and whether we felt it to improve thickness, reduce fallout or support healthy regrowth.
For each of the hair serums we've featured, we're working on getting them tested on even more editors with different hair types, textures and concerns – and over time, you'll be able to see results illustrated by even more video.
For total visibility, there's a list of hair growth serums at the bottom of this guide that I haven’t personally trialled but which are currently being tested by a Glamour contributor or myself. To ensure they're still worthy of a (albeit snappy) place on this page, I've still done a deep dive: comparing formulas to those we have tested, speaking to hair experts and trichologists, and pulling insights from real customer reviews to make sure they deserve a spot here.
I’ve been a beauty journalist for six years now, five at The Mirror and one at Glamour, and testing products has always been part of the job. But my interest in hair growth serums became personal last year in the lead-up to my wedding. After Googling “how to grow my hair” more times than I’d like to admit, hair serums were the one product that kept coming up again and again. I’ve never struggled with thickness, but length was a different story, especially after years of bleach damage. I was determined to go extension-free on my wedding day, so investing in a hair growth serum felt like a non-negotiable.
I won’t pretend one serum single-handedly transformed my hair. I was also booking regular trims, using weekly hair masks and seriously cutting back on heat styling. But I genuinely believe a good hair growth serum played a huge role in helping me retain length and improve overall condition. Now my hair is the longest and healthiest it’s ever been. That said, it’s not a quick fix. Growth takes time and consistency, so if you’re working towards a big event like I was, I’d recommend starting at least six months in advance to really see the benefits.
READ MORE: The best eyebrow growth serums our team has tried, or shop our guides on the best eyelash growth serums.
The UKHair serum is lightweight and doesn’t leave your roots greasy.
I started using the UKLash Hair serum before my wedding.
Condé NastWhy we love it: "The UKLash Hair Serum is the serum I’ve used most consistently over the past few months – and which has genuinely made a difference to my hair. My regrowth around the hairline is stronger and fuller, and even my hairdresser commented on the difference in density.
"It's lightweight, doesn’t leave your roots greasy – and the formula is packed with scientifically proven active ingredients that work to repair, protect and promote healthy hair growth. TBH, one glance down the ingredients label left me convinced it'd do its job. For me, the stars of the show are AnaGain™(Pea Sprout Extract), Phytic Acid and Turmeric. These three heroes work together to revitalise and stimulate hair growth at the scalp, while the addition of Lemon Fruit Water conditions and protects the hair follicle, preventing breakage and in turn reducing hair loss.