According to Matias, "Hyaluronic Acid will help to plump the hair, making it look and feel fuller." OPTIMIZED's hydrating mist is a favorite among reviewers because it does just that, in addition to strengthening and moisturizing strands without weighing them down. Since it also contains pH-balanced, vitamin-rich ingredients like biotin, sea buckthorn, and coconut oil, you can even use it on your skin, too.

"One of the best ways to encourage growth and to maintain thicker, fuller hair is to use a shampoo and conditioner that is designed specifically for this," says Butler. "I recommend Actiiv shampoo," which works like your standard shampoo — only it restores strands using plant-based compounds. "Actiiv cleanses your scalp and removes buildup that prohibits growth."

After thoroughly cleansing, Butler recommends conditioning your hair with Actiiv's Recover thickening conditioner. "The only extra step is to leave it on for a few minutes which gives you an opportunity to clean the rest of your body like normal and then rinse away. [...] Their ingredients also are designed to nourish the hair strand and follicle so you are set up for success," Butler notes.

Matias loves "the Wet Brush when it comes to detangling. The bristles are soft and flexible so it easily glides through your tresses." Available in a wide variety of colors, this tool minimizes breakage and damage when brushing especially thin or curly hair — and even though it's called "The Wet Brush," buyers have used it on dry hair without issue, too.

New York-based stylist Rebecca Yang told Bustle she "swears by" this Kevin Murphy Plumping Wash when it comes to thickening and strengthening fine hair. The formula uses ginger root and nettle extracts to invigorate the scalp and reduce DHT — a hormone that can cause hair loss. It also detoxifies and cleanses strands without stripping them of their natural oils.

During shampooing, Matias says, "Make sure you are really massaging your scalp to get blood circulating. It’s amazing to see how many people carry all of their stress in their heads." The Maxsoft scalp brush is an Amazon cult favorite because it helps you achieve a deep, relaxing cleansing every time you shower. The soft silicone bristles encourage circulation, remove buildup, and help your shampoo clean better, while the ergonomic handle is comfortable and waterproof. Choose from three colors.

This liquid hair supplement contains a cocktail of vitamins and minerals like vitamin C, folate, and Vitamin B-12 that you can add to smoothies or juices (or enjoy alone) to help promote strong hair follicles and hair growth, as well as clearer skin and more robust nails. One reviewer noted she has tried every hair vitamin and this one is the best: “Within 3 weeks, my roots were THICK. It was the most growth I experienced all winter long.”

"Protecting your hair is so important," Butler says. "Blow dryers and straightening or curling irons will force a tremendous amount of heat on your hair. A good thermal protectant will coat the hair and help to create a barrier against high heat." HSI PROFESSIONAL is one of the most versatile and popular options on the market. It's sulfate-free, works with all types of styling tools, and uses argan oil to protect your hair up to 450 degrees Fahrenheit.

For those who regularly use flat irons or curling irons, "you may want to invest in products that protect against up to 350 degrees of heat," notes Matias. "My go-to for iron work is Serum Therapiste from Kérastase." In addition to protecting hair against high-heat tools, it also reinforces strands with special repairing fibers, which minimize split ends while maximizing elasticity. Buyers say it's also non-greasy and has a pleasant scent.

"My salon stylist had me try this product for my delicate, thin hair," one reviewer wrote. After trying PURA D'OR's scalp serum, the customer "noticed my scalp is calmer and less irritated! My hair looks fuller/thicker. After my first bottle I had to purchase another." In fact, countless buyers have had great results with the formula, which is loaded with 15 growth-encouraging ingredients like argan oil, biotin, caffeine, stem sells, and DHT blockers.

For a conditioner that helps to protect fragile hair, this anti-thinning conditioner is a highly rated pick that contains biotin, moisturizing argan oil, and amla oil to encourage hair growth. This sulfate-free conditioner keeps strands smooth and thicker looking and one reviewer said, “I have used this conditioner for over a year, and it is the best! My post menopausal hair thinning has become a thing of the past, and my hair looks and feels like it did before menopause.”

"I am a hair stylist and love this product. It works great on fine thin hair WITHOUT it feeling dirty or gummy," one reviewer wrote. "I have used it alone or with other products and find it performs really well." And, according to BOLDIFY thickening spray's 4.4-star rating, thousands of others agree that it's an easy way to boost texture and volume in under 60 seconds, all without weighing hair down.

The Revlon One-Step is a cult-favorite tool because it dries, styles, and volumizes hair — in one easy step, and while causing way less damage than a standard straightener or curling iron. Since it's a brush and blow dryer in one, it directs hot hair through the bristles so you can style hair in a single pass. It's also made with a ceramic coating and a negative ion generator to further reduce damage. "My hair is now growing thanks to this," one buyer wrote.

According to dermatologist Joshua Zeichner in an interview with Bustle, Viviscal's supplements help "provide the building blocks to the scalp so follicles can function optimally." This supplement contains ingredients like zinc, biotin, vitamin E, horsetail extract, and iron, all of which help to nourish follicles from the inside out. In short, it has a 4.5-star rating on Amazon because reviewers rave, "Viviscal brought thickness and length."

"Biotin is also a great natural supplement to aid in the hair growth process," Matias says — but there are tons on the market to choose from. This certified vegan biotin supplement is non-GMO and includes calcium. Each veggie soft-gel contains 10,000 micrograms of biotin to support hair growth — and it helps with nails and skin, too.

"Does it dry your hair faster? Yes! Does it cut down on frizz? Yes! Is it super absorbent? Yes! My hair stylist has told me to switch to microfiber towels to dry my hair and now I understand why," one reviewer wrote. In fact, hair stylists regularly recommend the DuraComfort towel because the soft microfiber material minimizes damage and breakage. It's also lightweight so it doesn't put pressure on your roots and removes excess water so you need less heat for styling.

If you "can't seem to grow [your] hair past a certain point," Matias recommends "Extentioniste from Kérastase, which will help to promote longer, stronger hair." The formula is designed to target weaker strands, helping you get past the point of no new growth. It's also cleansing enough to lift away dirt, oil, excess product, and impurities from the scalp, but does so gently while adding nourishing lipids.

Dozens of reviewers say their stylists recommended the Black Orchid hair diffuser, which helps you to create defined, frizz-free curls as an alternative to excessive heat styling. It fits on any hair dryer with a 1.8-inch diameter; then it directs the air through the ventilated fingers, which are extra long to encourage strands into ringlet shapes. The 360-degree airflow dries hair quickly while minimizing damage, and the inner seal helps the tool to stay in place.

According to Butler, "If you are pulling your hair up please avoid elastic rubber bands. They create a high amount of pressure in a specific area. This can weaken the hair and cause breakage." Unlike most elastic options, J-MEE hair bands are soft, seamless, and made with stretchy cotton. They're designed to prevent damage, but they still offer a slip-free hold for various hairstyles. You can get this pack of 100 in three colors combinations: neutrals, rainbow, and all black.

Additionally, Matias says the "Invisibobble is a unique hair tie that really helps to reduce breakage because of its lightweight low-tension hold." Unlike elastic-based hair ties, this one uses a spiral design that gently holds hair up without slipping and without creating creases. Thanks to its smooth surface, it won't tangle or damage hair.

Another stylist favorite: these heat-free curling rods from Tifara Beauty. "I have been trying to grow my hair for years and it has been a long and extremely slow process," one reviewer wrote. "It has also been difficult to find cute hair styles that are 'damage free' until I bought these. I am actually amazed at how well these work." When wrapped into damp hair, the flexible interior holds strands in place while the lightweight foam cushions your head and wicks excess moisture. By morning, reviewers have "beautiful ringlets" with minimal effort and breakage.

When it comes to regrowth, this treatment is a popular one — both among experts and reviewers. "Rogaine foam contains an ingredient called minoxidil, which has been clinically shown to improve thinning hair," dermatologist Zeichner told Bustle. This two-month supply conditions the scalp, exfoliates away old skin that may be blocking follicles, and creates a healthy environment for hair growth. (The company also makes a similar treatment for men.)

This massaging brush combines vibration for circulation, blue illumination for anti-inflammatory effects, and red light wavelengths for strength and growth. It's also USB-rechargeable for convenience. So far, reviewers say it's easy to incorporate into their routines and actually helps with hair regrowth.

Experts:

Patrick Butler, technical director of education at Floyd's 99 Barbershop

Jonathan Matias, lead stylist and colorist at [salon]718 in Brooklyn, New York

Erin Palinski-Wade, RD, CDE, dietician and author