Frequently asked questions
Keratin is a structural protein that makes up the outer layer of your hair, says hairstylist Elizabeth Rexroat, owner of STRND Premium Hair Studio. Over time, factors like heat styling, chemical treatments, coloring, and environmental stress can deplete keratin, leaving hair weak, frizzy, or brittle. Keratin-infused products help temporarily fill in gaps along the hair shaft, smoothing the cuticle and improving the look and feel of damage. Keratins in products provide strength, improve elasticity, and can reduce frizz and damage,” Rexroat says.
Do keratin shampoos really work?
Yes—but it depends on the formula and how it’s used. “Keratin smooths and strengthens the hair. It also adds so much shine,” says hairstylist Lona Vigi. Some formulas focus heavily on strengthening without enough hydration, which can actually increase breakage over time. That’s why most pros recommend alternating between keratin and moisturizing shampoos, especially if your hair isn’t severely damaged.
“Some are only going to give you a strengthening element, which isn’t always the best for the hair,” she explains, saying that too much strength and not enough moisture will harden the hair to the point that it can’t bend and move. “That will actually leave you with more breakage,” she says.
This isn’t an everyday shampoo. Unless your hair is particularly fragile or processed, you’re better off alternating a keratin shampoo with a moisturizing formula to keep everything balanced. “Keratin shampoos are best used in rotation with moisturizing shampoos, especially if your hair isn’t severely damaged or chemically treated. Balance is key,” says Cavalcante.
Who is a good candidate for keratin shampoo?
Some formulas focus heavily on strengthening without enough hydration, which can actually increase breakage over time. That’s why most pros recommend alternating between keratin shampoos and moisturizing ones, especially if your hair isn’t severely damaged.
“I will recommend a keratin shampoo to a client who just had a blonding service and needs to replenish the moisture and strength that the color service altered,” says Rexroat. “I will also recommend it to the client whose hair breaks while brushing and has a ‘snowing’ effect [dandruff] even when taking the best care of it.”
“Keratin shampoos are a great support for damaged hair, but they don’t necessarily have the ability to repair it,” says Cavalcante. It can make your hair’s surface smoother and appear healthier, but he recommends a proper in-salon keratin treatment if you’re looking for a more permanent fix.
Is biotin or keratin shampoo better?
Biotin and keratin shampoos have different purposes, says Cavalcante. “Keratin will give a smoothing effect, while biotin is great for scalp health and growth. To get all these benefits, you can find a shampoo that contains both ingredients or rotate the two ingredients every other shampoo,” he explains.
How often should you use a keratin shampoo if you’ve had a keratin treatment?
It’s important that you don’t confuse keratin shampoo with a keratin “safe” shampoo, says Tiffanie Richards, an NYC-based colorist. A keratin ‘safe’ shampoo is a gentle formula you can use if you’ve gotten a keratin treatment, while a keratin shampoo usually has keratin in it. Often, keratin-safe shampoos are free of sulfates and sodium chloride that may break down the in-salon treatment that you want to preserve.
That being said, “you don’t want to overdo the keratin if you have had a treatment,” she says. If your hair is feeling dry and damaged, you can use a keratin shampoo once or twice a week, she notes. Cavalcante recommends alternating between a hydrating shampoo and a keratin-based shampoo to keep a good balance. “Too much protein can result in dry strands,” he shares.
Are there downsides to using a keratin shampoo?
Richards agrees that too much protein can make your hair feel stiff and dry, so you definitely don’t want to overuse a keratin shampoo. It’s also important to note that keratin shampoos won’t cure damaged hair, rather, you can get best results by including it into an existing regimen a few times per week, in addition to a strengthening shampoo. “This combo usually does more long-term than relying on keratin alone,” says Richards. Best results will also come from minimizing heat styling in your hair routine, and always using a heat protectant cream or spray when you use a hot tool.
How we evaluated keratin shampoos
We tested keratin shampoos by evaluating their ingredients, the experience of using them, and their efficacy at keeping our strands silky smooth and frizz-free. Testers aged between 30 and 35 tested over a dozen formulas to narrow it down to seven with potent keratin formulas. The best shampoos also included hydrating ingredients such as coconut oil, shea butter, aloe vera, or glycerin to ensure strands did not get stripped or dried out. They also featured antioxidants like vitamin E, as well as a keratin complex that worked to make strands look and feel softer and smooth. The best keratin shampoos also lathered well and washed out easily, and we noticed a near-immediate difference in the texture of our hair post-wash. Finally, the best ones actually gave us touchably smooth strands and kept flyaways at bay.
