Relaxing your hair permanently straightens it by breaking the internal bonds that give each strand its natural curl pattern. A chemical cream penetrates the hair shaft and restructures it from the inside out, so curly or coily hair lies flat. The change lasts until new growth comes in, which is why touch-ups are needed every 6 to 12 weeks.
How Relaxers Change Your Hair’s Structure
Each strand of hair gets its shape from tiny chemical bridges called disulfide bonds, which link protein chains inside the hair’s inner layer (the cortex). Curly and coily hair has these bonds arranged in a pattern that pulls the strand into spirals. A relaxer breaks those bridges apart using a strong alkaline solution, allowing the protein chains to shift. Once the hair is smoothed straight, a neutralizing step locks the bonds back into place in their new, straightened position.
This isn’t a surface-level change. The relaxer’s high pH forces open the outer protective layer of the hair (the cuticle), like lifting shingles on a roof, so the chemicals can reach the cortex underneath. That’s why relaxed hair behaves so differently from natural hair: the fundamental architecture of each strand has been rearranged.
Lye vs. No-Lye Formulas
There are two main types of relaxers, and the difference comes down to the active ingredient. Lye relaxers use sodium hydroxide, which is extremely alkaline and works quickly. They tend to straighten more effectively but can be harsher on the scalp. No-lye relaxers use a two-part system: one component contains guanidine carbonate, and the other is an activator, usually calcium hydroxide. You mix them right before applying. When combined, they form guanidine hydroxide, which is gentler on the scalp but can leave mineral deposits on the hair that make it feel dry over time.
Both types work through the same basic mechanism: raising the pH high enough to open the cuticle and break disulfide bonds. And with both, the degree of straightening is directly tied to the degree of damage. Reducing the concentration of the active chemicals results in less straightening but also less harm to the hair.
What Happens to the Hair Shaft
Relaxing takes a real toll on the physical structure of your hair. Research published in the Anais Brasileiros de Dermatologia describes what happens under a microscope: the scales of the cuticle lift and separate, their edges become irregular, and fissures can form. In some cases, the cuticle lifts so severely that the inner cortex is exposed. The distance between individual cuticle scales increases, meaning the hair’s protective barrier is permanently compromised.
This damage shows up in practical ways. Relaxed hair absorbs water more easily because its protective layer is disrupted, but it also loses moisture faster. It becomes more porous, which is why it can feel dry even shortly after conditioning. Breakage resistance drops, so strands snap more easily under tension. The hair also loses some of its natural elasticity, the springy quality that lets a strand stretch and bounce back without breaking.
Signs of Overprocessing
If a relaxer is left on too long, applied too frequently, or overlaps onto previously relaxed hair, you can end up with overprocessed strands. The telltale signs are hard to miss once you know what to look for. Overprocessed hair feels dry and sometimes “gummy,” meaning thin and stringy when wet, almost like it could dissolve between your fingers. It may lie in random directions and be full of flyaways.
You might also notice uneven texture: some sections look straight while others appear crimped or wavy, because the bonds were damaged inconsistently. Breakage often shows up as short, broken pieces around the hairline or crown. Split ends multiply, and hair can hang limp from their weight, giving an uneven, ragged appearance. If your hair reaches this point, the damaged portions can’t be repaired and need to be trimmed away over time.
Caring for Relaxed Hair
Because the cuticle has been permanently altered, relaxed hair needs consistent help maintaining moisture and strength. The two pillars of a relaxed hair routine are hydration and protein, and they need to stay in balance. Too much moisture without protein leaves hair mushy and weak. Too much protein without moisture makes it stiff and brittle.
For moisture, look for water-based deep conditioners, leave-in conditioners, and products containing humectants like glycerin or aloe vera. These help replace the hydration that porous, relaxed hair constantly loses. For strength, periodic protein treatments containing ingredients like keratin, hydrolyzed wheat protein, or silk protein help reinforce the weakened hair shaft and reduce breakage. Most people with relaxed hair benefit from alternating between moisture-focused and protein-focused deep conditioning sessions.
Immediately after relaxing, a neutralizing shampoo is essential. Its job is to bring the hair’s pH back down from the extreme alkalinity of the relaxer to a normal, slightly acidic range (around pH 4.5 to 5.5). Skipping this step or rushing through it leaves residual chemicals in the hair, which continue breaking bonds and cause progressive damage.
Long-Term Health Concerns
Repeated relaxer use over years has been linked to a form of permanent hair loss called central centrifugal cicatricial alopecia, or CCCA. This condition, seen primarily in women of African descent, causes scarring on the scalp that destroys hair follicles, starting at the crown and spreading outward. A study in the International Journal of Trichology found that women diagnosed with CCCA were more than 12 times as likely to have used chemical relaxers compared to women without the condition.
Beyond hair loss, a large study tracking nearly 34,000 women over 11 years raised concerns about broader health effects. Researchers at the National Institute of Environmental Health Sciences found that women who used hair straightening products more than four times in the previous year were more than twice as likely to develop uterine cancer. Among women who never used straighteners, an estimated 1.64% would develop uterine cancer by age 70. For frequent users, that number rose to 4.05%. The same research team had previously identified links between straightening chemicals and increased risk of breast and ovarian cancer.
These findings don’t mean that everyone who relaxes their hair will experience these outcomes. But they’ve prompted many people to weigh the cosmetic benefits against potential risks, particularly with long-term, frequent use.
What Relaxing Won’t Do
A relaxer only affects the hair that exists at the time of application. New growth comes in with your natural curl pattern, which is why a visible line of demarcation develops between the straight, relaxed ends and the curly roots. Touch-ups target only the new growth to avoid overlapping chemicals onto already-processed hair, which is one of the most common causes of breakage and overprocessing.
Relaxing also won’t make damaged hair healthy. It’s a permanent chemical alteration, not a treatment. If hair is already compromised from color, heat styling, or previous chemical services, adding a relaxer on top compounds the damage rather than improving the hair’s condition. Starting from a healthy baseline and spacing applications appropriately gives the best results with the least structural harm.