When I think of hydrogen peroxide, the liquid in the brown bottle next to the alcohol in my local drugstore comes to mind. I also think of all the ways it can be used: To treat a cut, make a mouthwash, and of course, lighten your hair.
While many people have used hydrogen peroxide on their hair in the pursuit of lighter tresses, that age-old question remains: Should you use this chemical on your strands? Ahead, we get to the bottom of whether or not hydrogen peroxide is safe for your hair with the help of Pureology global artistic director Jamie Wiley, board-certified dermatologist Yoram Harth, MD, and trichologist Helen Reavey.
Meet the Expert
Keep reading to find out everything you need to know about hydrogen peroxide for hair.
Hydrogen Peroxide for Hair
Type of ingredient: Colorless, liquid chemical
Main benefits: Lifts pigment from hair to create a lighter color (think: blonde shades)
Who should use it: In general, anyone can use hydrogen peroxide on their hair. However, it should only be used in a professional salon or at-home formulas created by experts.
How often can you use it: Hydrogen peroxide should not be used more frequently than every six weeks.
Don’t use with: Because hydrogen peroxide is a chemical, it is best not to use it with other chemicals in the same hair process.
What Is Hydrogen Peroxide?
"Hydrogen peroxide is a chemical compound that is used as an oxidizer, bleaching agent, and antiseptic," says Wiley. "[It] will lift the natural melanin from the hair because it works in the hair cortex, the innermost part of the hair that holds the pigment that gives hair its color."
She continues: "Hydrogen peroxide is labeled using a percent or a volume. Both measurements indicate the concentration of oxygen available contained in the bottle. The percentage indicates how much of the content in the bottle is pure hydrogen peroxide [and] the volume indicates the volume of oxygen that is released for every milliliter of content."
Who Can Use Hydrogen Peroxide on Their Hair?
While hydrogen peroxide is frequently used to lighten hair in salon settings—and you can very much leave the salon with your hair healthy and intact—there are things to consider when you use any chemical on your hair. Among these considerations are the health of your strands and scalp. This is especially true when you're thinking of using hydrogen peroxide: Since it is essentially a bleaching agent that lifts pigment and lightens the hair, damage is possible. "Hydrogen peroxide, particularly at high potencies, can be very irritating to the scalp and can lead to weak hair, scalp dermatitis, and even hair loss if not used appropriately," says Reavey.
What Are the Drawbacks of Using Hydrogen Peroxide on Your Hair?
One of the major drawbacks of hydrogen peroxide is that it permanently alters the hair. "Once this pigment has been removed, your hair color has been permanently altered and cannot be reversed," Reavey explains. "The only way to add color back into the cuticle is by depositing a new color onto the hair." Additionally, she says that continued use of hydrogen peroxide and other chemicals commonly used with it—such as ammonium persulfate and ethyl alcohol—can strip moisture from the hair follicles, leaving your hair and scalp dehydrated.
Harth adds that because hydrogen peroxide needs to penetrate the outer layer of the hair—the cuticle—hair and scalp damage can be an issue. "The cuticle damage leads to breakage, split ends, and frizz of the hair," he says. "As a potent oxidizing compound, hydrogen peroxide can irritate the scalp, damage the hair follicles, and increase hair loss. One study found that hydrogen peroxide (H2O2) suppresses hair growth through the downregulation of β-catenin, afunctional protein that has a role in hair growth."
How Can You Use Hydrogen Peroxide on Hair?
With all of the above in mind, Reavey emphasizes avoiding at-home treatments. "You should always go to a hair color professional for color and avoid at-home treatments, as these can be especially dangerous when not applied correctly. Misuse can lead to blisters on the scalp and possible scar tissue if not mixed correctly."
Are There Alternatives to Using Hydrogen Peroxide on Hair?
If all that information about what hydrogen peroxide can do to your hair and scalp has you a little spooked, we've got good news: You have plenty of alternatives. "A great option is using ammonia-free hair dye when coloring your hair," Reavey tells us. "Ammonia-free hair dyes typically do not need to be formulated with hydrogen peroxide, making it ideal for those with sensitive scalps. Another great option is [asking] your stylist to use coloring techniques like balayage that allow you to go longer periods of time in between colorings without feeling the need for a touch-up. The less frequently your scalp and hair are exposed to peroxide, the better."
