Thinning Hair Is Hard, But These Hair-Growth Serums Can Help (2024)

Is your part looking a little wide? Hair feeling thin? First, the good news: Finding the best hair-growth serum, available over-the-counter and in your local beauty aisle, can wave a thickening wand over your hair, making your strands fuller, denser, and more ripe for flipping or fluffing after a few months. But alas, the serums aren’t a cure-all for hair loss. “If one has active hair loss it is important to see a board-certified dermatologist, as there can be underlying issues or a hormonal component at the root of it,” says Margarita Lolis, MD, a board-certified dermatologist and Mohs surgeon based in New Jersey. “With that said, if you just want to promote hair growth and thickness then there are many hair-growth serums available.”

Ahead, Dr. Lolis and other board-certified pros weigh in on the ingredients to look for in the best hair-growth serum (and how they work), provide their recommendations for the most effective formulas you can snap up without a subscription, and deliver some hard truths about what these serums can’t do—and what they certainly can’t do overnight. Nevertheless, anyone looking for smoother, stronger hair can trust that the selection below represents the best serums for bringing your healthy hair visions to life.

Our Top Picks

• Best Hair-Growth Serum Overall: Curology Hair Formula Rx, $90
• Best Pre-Shampoo: Ranavat Fortifying Hair Serum, $70
• Best for Fine Hair: Isdin Lambdapil Hair-Density Leave-In Lotion, $70
• Best for Long Hair: Nutrafol Hair Serum,
• Best Splurge: Sisley-Paris Fortifying Serum for the Scalp, $230
• Best Budget: The Ordinary Multi-Peptide Treatment for Hair Density, $23
• Best for a Dry Scalp: Act + Acre Cold Processed Stem Cell Serum, $86

Frequently Asked Questions

• What serum is best for hair growth?
• Do hair-growth serums work?
• How long does it take to see growth?
• Meet the experts
• How we test and review products
• Our staff and testers

Best Hair-Growth Serum Overall: Curology Hair Formula Rx

Why we love it: Minoxidil, found in classic hair-loss treatments like Rogaine, is one of two topical drugs that the Food and Drug Administration has approved to treat hair loss. (The other, FYI, is finasteride.) “Minoxidil helps prevent the hair from going into sleep mode,” Morgan Rabach, MD, a board-certified dermatologist based in New York, explains. She’s referring to the telogen (or resting) phase of hair growth, in which hair follicles are dormant and the hair stops growing for a time. Hair-growth serums work “only if they have an active ingredient like minoxidil,”says Dr. Rabach, which brings us to Curology’s Hair Formula Rx. The treatment works a little differently from the others on this list: Each treatment is personalized by a dermatologist associated with the brand. To get your customized growth potion, you’ll start by snapping some selfies, answering questions about your hair, and scalp, and then sharing your answers and pics with the brand. After a dermatologist reviews everything, you’ll get a personalized formula containing up to three active ingredients, which could include minoxidil, finasteride, or ketoconazole (an antifungal medication). The treatment is delivered as part of a shipment that provides enough formula for two months; the treatment typically takes three to six months to show a noticeable difference in hair.

Editor Tip: While all genders are FDA-approved for minoxidil use, finasteride is only FDA-approved for use on men.

Key ingredients: ingredients vary, but may include minoxidil, ketoconazole, or finasteride | Who it’s for: The personalized formulas cater to all hair types

Best Pre-Shampoo: Ranavat Fortifying Hair Serum

Why we love it: The Ranavat Fortifying Hair Serum Mighty Majesty is a favorite of Kiran Mian, MD, a board-certified dermatologist at Hudson Dermatology and Laser Surgery in New York City. The flyaway-taming potion blends jasmine oil (for hydration and softness), amla extract (to promote hair growth), and sunflower oil (which helps with frizz control and scalp health.) In all, the serum makes for a smoothing potion that boosts the hair’s shine while protecting it from heat damage. “I love its texture,” Dr. Mian says. “The pump makes it easy to apply, and the formula is not too sticky, making it easy to wash out.”

Editor tip: The serum can be used as an overnight mask. Just dispense a single pump into your hand, work it through your hair. Alternatively, the versatile salve works on wet or dry hair to tamp down flyaways in a pinch.

Key ingredients: alma extract, jasmine oil, sunflower oil | Who it’s for: damaged, frizzy, dandruff-prone hair

Best for Long Hair: Isdin Lambdapil Hair-Density Leave-In Lotion

Why we love it: Lolis has seen promising results from Isdin’s leave-in lotion, which comes with an extended tip designed for easy application, even in longer hair. As for the formulation, “it’s designed to promote hair growth and reduce thinning by nourishing the scalp and strengthening hair follicles,” Dr. Lolis explains. “It contains key ingredients like biotin, caffeine, and zinc, which work together to improve hair density and resilience without leaving a greasy residue.” Curious about how the ingredients work, exactly? “The caffeine stimulates blood flow to the scalp, supporting healthy hair follicles and encouraging hair regrowth, while biotin and zinc help reinforce hair structure, making it stronger and more resistant to breakage,” she says.

Editor tip: Don’t be afraid to use this liberally. The brand recommends using the lotion at least five days a week and spraying it 14 times with each application.

Key ingredients: dyaminopyrimidne oxide, ginkgo biloba extract, D-biotin | Who it’s for: thinning, oily or fine hair

Best for Fine Hair: Nutrafol Hair Serum

Why we love it: “Nutrafol Women Hair Serum is a powerful topical treatment designed to support visibly thicker and stronger hair,” Dr. Lolis says. She points to its key ingredients—ashwagandha exosomes, pea sprout extract, and maca—as a powerful cocktail for better scalp health and reduced hair breakage. Now, about that ashwagandha: Though the ingredient is thought to help stimulate keratin production and is commonly used in hair potions promising thicker, stronger, healthier hair, Nutrafol’s version of the adaptogen is a bit different. “The ashwagandha exosomes are unique to Nutrafol and are 1500 times smaller than regular ashwagandha,” Dr. Lolis explains. “This allows deeper penetration into the scalp to promote cell renewal and create an optimal environment for hair growth.”

Editor tip: The product has been tested in clinical studies, which had promising results. “Eighty-seven percent of users saw healthier hair in 30 days, and significant improvements in thickness and strength within 90 days of consistent use,” Lolis says.

Key ingredients: ashwagandha exosomes, pea sprouts, Irish moss peptides | Who it’s for: thinning hair

Best Splurge: Sisley-Paris Fortifying Serum for the Scalp

Why we love it: Granted, the price of this French splurge is a little steep, but hear us out. Rather than a drop-it-and-go product, which has its time and place, this serum lends itself to a luxurious experience. First, there’s its addictive fragrance. The blend of citrus, peach blossom, lemon, amber, and verbena doesn’t just smell like a swish salon— it was concocted with ingredients that boost the efficacy of the product. (For example, amber extract is commonly used to treat hair fall, while verbena is thought to stimulate hair growth.) Then, there’s the gossamer-light texture, which lends itself to a lovely scalp massage. But it’s not all pampering: The serum is infused with a highly concentrated blend of plant extracts, vitamins, and minerals to soothe the scalp and strengthen the hair.

Editor tip: If your hair’s looking a little dull, this is even more worth the splurge. Thanks to ingredients like Einkorn wheat and linseed extract, the serum gives the hair an undeniable shine.

Key ingredients: fortifying vitalizing complex (zinc, copper, magnesium, vitamin B, vitamin E), rice protein, vitamin peptide | Who it’s for: irritated scalp

Best Budget: The Ordinary Multi-Peptide Treatment for Hair Density

Why we love it: Known for affordable skincare with few bells and whistles and lots of highly concentrated ingredients, The Ordinary puts peptides at the heart of the The Ordinary Multi-Peptide Treatment for Hair Density. Buzzy in the land of skin care for their ability to stimulate collagen and elastin production, peptides are key players in scalp health as well. The amino-acid chains are known to increase blood flow, help hair follicles grow, and tamp down inflammation—all ideal for hair growth. “This is an affordable and effective option,” Dr. Lolis says of the under-$25 salve. “It utilizes peptides, caffeine, and zinc to strengthen hair at the roots, exfoliate the scalp, and improve circulation. I also love this serum for those with dandruff-prone scalps as it helps reduce buildup and inflammation.”

Editor tip: The lightweight formula is designed as a leave-in treatment. Massage it into a clean and dry scalp once a day—preferably at night, so it can treat the scalp as you sleep.

Key ingredients: peptides, caffeine, zinc | Who it’s for: thinning hair, hair loss, dandruff

Best for a Dry Scalp: Act + Acre Cold Processed Stem Cell Serum

Why we love it: Act + Acre is the brainchild (scalp-child?) of Helen Reavey, who’s not only a hairstylist but Harry Styles’s go-to trichologist. She designed the line to bring a premium touch to scalp care, and her Cold Processed Stem Cell Serum is a cult classic among beauty editors and industry pros. The formulation’s star ingredient is apple stem cells, which have been cold-processed to keep their nutrients intact. Acting as growth factors for the hair, the stem cells help reduce hair thinning and fallout; they also increase hydration and boost collagen production. If you’re scratching your scalp as you read this, this part is for you: The serum also contains aloe vera, which instantly soothes itchiness and keeps the scalp hydrated in the long term.

Editor tip: In an instructional video for the serum, Reavey divulged one of its off-menu perks: the hydrating potion can also be used on the face.

Key ingredients: apple stem cells, bamboo leaf extract, pea extract | Who it’s for itchy, dry scalp

Best for a Sensitive Scalp: Vegamour GRO Hair Serum

Why we love it: The Vegamour GRO Hair Serum is one of Dr. Lolis’s go-tos. “It uses plant-based ingredients like red clover and mung bean to stimulate hair follicles, boost density, and reduce shedding,” she says. “It’s ideal for those experiencing thinning hair and has strong clinical evidence backing its claims.” On top of that, ”the serum is clean, lightweight, and safe for all scalp types—even sensitive scalps,” Dr. Lolis says. The recommended course of action: Apply a full dropper of serum to the scalp every day; results should start to show in about 90 days.

Editor’s tip: If the product is used as intended, each bottle should last about a month. Therefore, if you’re feeling good about this, you may want to stock up on a three-pack.

Key ingredients: turmeric, caffeine, mung bean and red clover blend | Who it’s for: thinning hair of all types and textures

Best Spray-On Serum: Aveda Invati Ultra Advanced Revitalizing Scalp Serum

Why we love it: Aveda’s Invati Ultra Advanced Revitalizing Scalp Serum is almost entirely made of naturally derived ingredients (it’s 94-percent natural, to be exact). Included is the brand’s Follicle Vitality Complex, a blend of three antioxidant-rich botanicals: eclipta prostrata, alpina, and ginger. “Antioxidants can protect the scalp from oxidative damage, which is critical for long-term hair health,” Dr. Lolis says. The serum comes in a spray bottle with an extended tip that targets hard-to-reach areas on the scalp. To use it, lift the hair in sections and spray the serum until it’s covered the whole scalp; then go about your day. Added perk: The scent is Aveda’s signature Pure-Fume, a spa-channeling mix of lavender, sage, sandalwood, and vanilla.

Editor tip: The serum was designed to work as part of a four-step system. For extra credit from the Aveda gods (or if you just really love the brand), try using the Invati Ultra Advanced Exfoliating Shampoo and Thicken Conditioner first, the Scalp Serum next, and the Fortifying Leave-In Treatment or Thickening Foam as a final touch.

Key ingredients: ginseng-turmeric blend, organic amla, Follicle Vitality Complex | Who it’s for: dry, thinning hair

Frequently Asked Questions

What serum is best for hair growth?

It’s okay to expect a lot from your hair growth serum, especially when you’re shopping for the best hair growth serum. “A good hair growth serum should reduce hair shedding, increase hair, diameter, increase the growth phase of hair, decrease scalp inflammation, and be gentle on the scalp,” Dr. Amin says. “The ingredients I look for are rosemary oil, amla oil, caffeine, green tea, and coconut oil, to name a few. These ingredients have been shown to improve hair strength, promote growth, and undo damage.”

Dr. Lolis adds that many common conditions that cause hair loss—including androgenic alopecia and telogen effluvium—are triggered by the hormone dihydrotestosterone (DHT), which can bind to hair follicles and cause them to shrink. “With androgenic alopecia, we typically prescribe medications that block DHT, an enzyme that causes hair loss. However, there are many natural DHT blockers to look out for such as saw palmetto and zinc,” she says. The Ordinary’s Multi-Peptide serum and Sisley-Paris Fortifying Serum for the Scalp

both contain zinc. Otherwise, Dr. Lolis suggests: “Look for active ingredients like biotin and caffeine, which improve hair strength and stimulate growth.”

Do hair-growth serums work?

“Many hair-growth serums include non-medicated ingredients,” Dr. Amin says. (Translation: You don't need a prescription for most of them.) “The efficacy of the serums is difficult to ascertain because there are not many randomized controlled clinical trials.”

However, anecdotally, Lolis has seen evidence that the serums work—especially when they’re used as intended. “Ingredients like biotin and caffeine support the scalp’s environment, helping nourish hair follicles, which can result in denser, stronger hair [over time],” she says. In short, the how-tos on the packaging are required reading, and you should try to adhere to the recommended guidelines if you want to feel blessed in the hair follicles department.

How long does it take to see growth?

“Most users report seeing visible improvements, such as reduced shedding and new hair growth, after about three months of consistent use,” Dr. Lolis says. Dr. Mian agrees, adding that patience is key here. “Hair-growth serums can take a while to show their efficacy,” she says. “I would use a serum for at least three months before deciding if it’s working or not.”

Meet the Experts

• Margarita Lolis, MD, a board-certified dermatologist and Mohs surgeon based in Hackensack, New Jersey.
• Kiran Mian, MD, a board-certified dermatologist at Hudson Dermatology and Laser Surgery in New York City.
• Morgan Rabach, MD, a board-certified dermatologist at LM Medical in New York City.

How we test and review products

We always enlist a range of testers for our makeup vertical, but hair-care products and tools are another story. While there are certainly products that can be used across different hair textures, lengths, curl patterns, thicknesses, colors (natural and unnatural), and needs, hair products are often created with specific consumers in mind. Many are created in order to address a concern (dandruff, breakage, brittleness) or to work most effectively for a specific hair type (4C curls, wavy hair, gray hair). You wouldn't want to pick up a purple shampoo that’s only been reviewed by someone with, say, auburn hair, or a diffuser that’s never been tested by anyone with curls—right?

For our review of the best hair growth serums, we enlisted the help of multiple editors, writers, contributors, and dermatologists to find the most hydrating, strand-softening formulas out there. Testers considered performance across four primary categories: efficacy, texture and experience, fragrance, and packaging. For more on what's involved in our reporting, check out our complete reviews process and methodology page.

Our staff and testers

A beauty product is a personal purchase. You might be searching for a face cream to address persistent dryness or a new nail product to add to your Sunday self-care routine; you may simply be browsing around for the latest launches to hit the hair market. No matter what you seek or your individual needs and concerns, Allure wants to ensure that you love anything we recommend in our stories. We believe that having a diverse team of writers and editors—in addition to the wide range of outside testers and industry experts we regularly call upon—is essential to reaching that goal.

After all, can we really say a skin-care product is the "best" for people over 50 if the only testers we've solicited opinions from folks who have yet to hit 30? Can we honestly deem a high-end diffuser worthy of your hard-earned cash if it’s never been tested on curls? We're proud that our staff spans a wide range of ages, skin tones, hair textures, genders, and backgrounds, which means that we are able to fairly assess any beauty product that comes into the beauty closet.

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