Relaxing your hair is a chemical process that permanently straightens naturally curly, coily, or kinky hair. It works by breaking the internal bonds that give your hair its curl pattern, then locking the hair into a new, straighter shape. The results last until new hair grows in, which means touch-ups are needed every 6 to 12 weeks to maintain a uniform look.
How Relaxers Change Your Hair
Your hair’s curl pattern is determined by tiny chemical connections called disulfide bonds inside each strand. These bonds link protein chains together and hold them in whatever shape your genetics dictate, whether that’s tight coils, loose waves, or something in between. A relaxer breaks those bonds apart using a strong alkaline chemical, allowing the hair to be smoothed into a straight position. Once the hair is straight, a neutralizing agent reforms the bonds in their new arrangement. The change is permanent for the hair that’s been treated.
This is the same basic chemistry behind perming, just in reverse. Where a perm wraps hair around rods to create curls before resetting the bonds, a relaxer smooths the hair flat. In both cases, you’re dissolving the hair’s internal structure and rebuilding it in a different configuration.
Lye vs. No-Lye Formulas
Relaxers come in two broad categories, and the difference matters for your scalp and hair health.
Lye relaxers use sodium hydroxide as the active ingredient. They work fast and straighten effectively, but they’re harsh. Their pH ranges from 12 to 14, which is extremely alkaline. That strength is why they’re effective, but it’s also why they carry a higher risk of scalp irritation and chemical burns.
No-lye relaxers use gentler alternatives like calcium hydroxide or guanidine hydroxide. Their pH falls between 9 and 11, making them milder on the scalp. Stylists often recommend them for people with sensitive skin. The trade-off is that no-lye formulas are commonly associated with calcium buildup on the hair, which can leave strands feeling dry and stiff over time. Clarifying shampoos help manage this, but it’s something to plan for.
What Happens During the Process
A relaxer appointment follows a specific sequence, and each step exists for a reason.
First, your stylist will not shampoo your hair. Clean hair and a freshly scrubbed scalp are more vulnerable to chemical burns, so you’ll typically be asked to avoid washing for a few days beforehand. Before any chemicals touch your head, a protective cream (usually petroleum jelly or a specialized base cream) is applied along your hairline and across the scalp to create a barrier against irritation.
The relaxer itself is applied in sections, starting about half an inch away from the scalp and staying away from the ends if they’re already processed or porous. The roots are done last because body heat from the scalp speeds up the chemical reaction there. Processing time depends on your hair’s thickness and condition: fine hair may need only 10 minutes, while coarse hair can take up to 18. Your stylist will check the straightening progress in multiple spots every few minutes.
Once the desired level of straightness is reached, the relaxer is rinsed out thoroughly with warm water for at least five minutes. Then a neutralizing shampoo is applied. This step is critical because it stops the chemical reaction and begins restoring the hair’s pH. Some neutralizing shampoos change color (turning pink, for example) if any relaxer residue remains, signaling the need for additional rinsing.
Touch-Ups and Timing
Because a relaxer only changes the hair that’s already grown out of your scalp, new growth will come in with your natural curl pattern. Most stylists recommend touch-ups every 6 to 8 weeks, though some people stretch to 10 or 12 weeks without issue. The general guideline is to wait until you have 1 to 2 inches of new growth.
Timing matters in both directions. Relaxing too soon risks overlapping the chemical onto previously treated hair, which can cause severe damage. Waiting too long creates a sharp line of demarcation between your straight ends and curly roots, and that junction point is fragile. Breakage tends to happen right where the two textures meet, especially during combing and styling.
How Relaxers Differ From Keratin Treatments
Relaxers and keratin treatments both make hair smoother, but they do fundamentally different things. A relaxer permanently breaks and restructures your hair’s internal bonds. A keratin treatment coats the outside of the hair strand with protein and conditioning agents, sealed in with heat. It reduces frizz and adds smoothness without altering the hair’s underlying structure, and it washes out gradually over a few months.
If you want your curl pattern gone entirely, that’s what a relaxer does. If you want your natural texture softened but not eliminated, a keratin treatment is the less permanent option. The two aren’t interchangeable, and layering a keratin treatment on top of relaxed hair requires caution to avoid overprocessing.
Signs of Overprocessed Hair
Relaxers work by breaking down protein bonds, and there’s a fine line between “straightened” and “damaged.” Overprocessed hair becomes highly porous, meaning it absorbs and loses moisture too quickly. You’ll notice it feels dry and rough, lies in multiple directions at once, and becomes difficult to style.
More advanced damage shows up as breakage, particularly in areas where the chemical sat too long or was applied unevenly. Some sections may look straight while others appear crimped or wavy. Hair can develop a gummy, stringy texture when wet, which is a sign that the protein structure has been severely compromised. Split ends multiply, and your hair may hang limp and look uneven. Frizz becomes a constant problem, which is ironic given that eliminating frizz is often the reason people relax their hair in the first place.
Once hair reaches this point, there’s no chemical fix. Deep conditioning can improve how it feels temporarily, but truly overprocessed hair usually needs to be trimmed away over time.
Health Concerns Worth Knowing
A large study from the National Institutes of Health found that women who used hair straightening products frequently (more than four times per year) were more than twice as likely to develop uterine cancer compared to women who never used them. To put that in perspective: among women who never used straighteners, about 1.64% were estimated to develop uterine cancer by age 70. For frequent users, that number rose to 4.05%. The same research team also found associations between permanent hair products and increased breast and ovarian cancer risk.
These findings don’t prove that relaxers directly cause cancer, but the statistical association is significant enough that researchers flagged it as a concern. The chemicals involved are absorbed through the scalp, and repeated exposure over years adds up. This is particularly relevant for Black women, who use these products at higher rates and start at younger ages than other groups.
Keeping Relaxed Hair Healthy
Relaxed hair has had its internal structure chemically altered, which makes it inherently more fragile than untreated hair. Moisture is the single most important thing you can provide. Regular deep conditioning treatments help replace the protein and hydration lost during the chemical process. Avoid heat styling more than necessary, since relaxed hair is already weakened and high temperatures compound the damage.
Protective styles that keep the ends tucked away reduce mechanical breakage from friction and manipulation. Sleeping on a satin or silk pillowcase (or wrapping your hair) prevents the rough surface of cotton from pulling moisture out of your strands overnight. And when it’s time for a touch-up, make sure the relaxer is applied only to new growth. Overlapping onto previously relaxed hair, even by a small margin, is one of the fastest routes to breakage and thinning.