How do hair relaxers alter hair structure?

Roots

The very strands that crown our heads, particularly those with a vibrant coil or a gentle wave, hold stories far older than any trend or technique. To truly grasp how chemical relaxers alter hair structure, one must first appreciate the inherent architecture of hair itself. It is a living fibre, a testament to biological artistry, born from the scalp and extending into the world, each curl and bend a unique expression of its genetic blueprint. Before we speak of change, we must speak of what is, in its most elemental form.

Hair, at its fundamental level, is a protein filament, primarily composed of Keratin. This remarkable protein is arranged in a sophisticated, layered construction, giving hair its strength, elasticity, and distinctive shape. From the outermost protective layer to the innermost core, each component plays a specific, vital role.

The Hair Shaft’s Inner World

Peering into the microscopic landscape of a single hair shaft reveals three principal layers ❉ the cuticle, the cortex, and the medulla.

• Cuticle ❉ This is the hair’s outermost shield, a transparent, protective layer composed of overlapping, scale-like cells. Think of it as a roof of tiny shingles, all facing downwards towards the hair tip. A healthy cuticle lies flat, reflecting light and giving hair its natural sheen, while also safeguarding the inner structures from environmental stressors and chemical assaults.
• Cortex ❉ Lying beneath the cuticle, the cortex is the heart of the hair shaft. It accounts for approximately 75-90% of the hair’s total weight. This is where the magic of hair’s characteristics truly resides. The cortex contains the long, twisted chains of keratin proteins, bundled together like microscopic ropes. Within these bundles are the pigment granules, melanin, which determine hair color. Crucially, the cortex is also home to the various bonds that give hair its strength and its natural configuration.
• Medulla ❉ The innermost layer, the medulla, is not present in all hair types or even all hair strands. It is a soft, central core, often appearing as a hollow canal. Its precise function remains a subject of ongoing scientific inquiry, though some theorize it may play a role in regulating heat or providing structural integrity in certain hair types.

The Bonds of Being

The resilience and shape of hair, particularly textured hair, depend heavily on the intricate network of chemical bonds within the cortical layer. These bonds are the invisible anchors that hold the keratin protein chains in their coiled or straight configurations.

Among these, the Disulfide Bonds stand as the strongest and most significant. These are covalent bonds formed between two sulfur atoms of the amino acid Cystine, a building block of keratin. Imagine these bonds as strong, rigid ladders connecting the protein chains, dictating the hair’s natural curl pattern.

The more disulfide bonds arranged in a particular way, the curlier the hair. When these bonds are broken or rearranged, the hair’s shape changes.

Other bonds, while less robust than disulfide bonds, also contribute to hair’s structure. These include Hydrogen Bonds, which are weaker and easily broken by water (allowing temporary styling like roller sets or blowouts) and salt bonds, which are also susceptible to changes in pH. These weaker bonds quickly reform as hair dries or its pH returns to normal, allowing the hair to revert to its natural curl pattern.

Understanding this intrinsic biological framework of hair, from its protective outer layer to its protein core and the chemical bonds that define its form, provides the essential context for appreciating the profound chemical intervention that relaxers represent. They do not merely smooth the surface; they reach deep within, seeking to dismantle and reassemble the very scaffolding of the hair shaft.

Hair’s innate architecture, primarily its keratin structure and disulfide bonds, sets the stage for any chemical alteration.

Ritual

The application of a chemical relaxer, for many, transcends a mere beauty treatment; it becomes a ritual, a passage, often steeped in personal and communal significance. This process, however, initiates a powerful chemical transformation, fundamentally reshaping the hair’s inherent structure. It is a delicate dance between potent chemistry and the desire for a particular aesthetic, a process that requires precise timing and understanding.

The Chemical Intervention

Hair relaxers are powerful alkaline formulations designed to permanently alter the hair’s natural curl pattern. They achieve this by targeting the very backbone of hair’s strength ❉ the disulfide bonds. There are primarily two types of chemical relaxers, each employing a distinct chemical agent to achieve the desired straightening effect:

1. Hydroxide Relaxers ❉ These are often referred to as “lye” relaxers (containing Sodium Hydroxide) or “no-lye” relaxers (containing Guanidine Hydroxide, Lithium Hydroxide, or Potassium Hydroxide). Hydroxide relaxers are exceptionally strong alkalis, with pH levels typically ranging from 12 to 14.
2. Thio Relaxers ❉ These utilize Ammonium Thioglycolate as their primary active ingredient, often at a pH around 10. While also alkaline, they are generally considered milder than hydroxide relaxers.

How Do Relaxers Break Bonds?

The fundamental action of both relaxer types involves breaking the disulfide bonds within the hair’s cortex. The mechanisms, however, vary.

Hydroxide Relaxers and Lanthionization

Hydroxide relaxers work through a process called Lanthionization. When these highly alkaline solutions are applied to the hair, the hydroxide ions (OH-) penetrate the cuticle and reach the cortex. Here, they react with the disulfide bonds, removing one sulfur atom from each bond and converting the remaining sulfur atom into a Lanthionine Bond.

This conversion is a permanent alteration. Once a disulfide bond is transformed into a lanthionine bond, it cannot reform back into a disulfide bond. This irreversible change is what gives hydroxide relaxers their powerful and permanent straightening capability. The hair’s natural coiled structure is effectively dismantled at its core, allowing the keratin chains to shift into a straightened configuration.

The hair is then smoothed and rinsed, and the new, straightened shape is set. Unlike thio relaxers, hydroxide relaxers do not require a separate neutralizing step to reform bonds; the lanthionine bonds are stable in their new arrangement.

Thio Relaxers and Reduction

Thio relaxers operate through a different chemical pathway, primarily a Reduction reaction. The ammonium thioglycolate acts as a reducing agent, adding hydrogen atoms to the sulfur atoms in the disulfide bonds. This addition breaks the disulfide bonds, converting the cystine amino acids into two separate Cysteine molecules.

Once these bonds are broken, the hair can be physically manipulated into a straighter shape. The hair is then rinsed, and a neutralizing solution, typically containing hydrogen peroxide, is applied. This neutralizing step is crucial for thio relaxers.

The oxidizing agent in the neutralizer removes the added hydrogen atoms, allowing the cysteine molecules to reform new disulfide bonds in the hair’s new, straightened configuration. This re-establishment of bonds locks the hair into its altered shape.

Relaxers chemically dismantle hair’s disulfide bonds through lanthionization or reduction, permanently reshaping the natural curl.

The application of relaxers is a precise procedure, demanding careful attention to timing and product selection. Over-processing can lead to significant damage, as the chemical agents continue to break down the hair’s protein structure beyond the point of straightening, leading to fragility and breakage. The strength of the chemical and the duration of its contact with the hair are critical variables in this chemical ritual.

Relay

Moving beyond the immediate chemical reaction, the story of hair relaxers extends into a more profound consideration of their long-term effects, not only on the physical hair strand but also within broader societal and health contexts. This is where the scientific understanding converges with lived experiences, revealing complexities that transcend simple cosmetic outcomes. The persistent use of these chemical agents raises significant questions about hair integrity, scalp health, and even systemic health disparities.

Long-Term Structural Integrity of Hair

The permanent alteration of disulfide bonds, particularly through lanthionization with hydroxide relaxers, fundamentally compromises the hair’s natural strength and elasticity. Hair that has undergone chemical relaxing often exhibits a reduced cystine content, the amino acid essential for forming strong disulfide bonds. This biochemical change renders the hair more susceptible to damage.

Consider the hair’s resilience ❉ naturally coiled hair, while appearing delicate, possesses a unique spring-like quality that allows it to resist breakage under tension. When this natural architecture is chemically straightened, the hair loses much of its inherent shock absorption. Microscopic studies have shown that relaxed hair frequently displays increased cuticle damage, with lifted or absent cuticle scales, leaving the inner cortex vulnerable. This damage can manifest as:

• Breakage ❉ The hair shaft becomes brittle and prone to snapping, particularly at the mid-shaft or ends.
• Dryness ❉ A compromised cuticle struggles to retain moisture, leading to chronically dry and dull hair.
• Thinning ❉ Repeated chemical exposure can weaken the hair strand itself, leading to a perception of reduced density over time.

A study by Khumalo et al. (2010) revealed that the cystine levels in frequently relaxed hair were comparable to those found in individuals with Trichothiodystrophy, a rare genetic disorder characterized by extremely fragile, brittle hair with abnormally low sulfur content. This striking comparison underscores the severe impact relaxers can have on the hair’s core protein structure, leading to a state of induced fragility.

Scalp Health and the Silent Burn

The highly alkaline nature of relaxers poses a direct threat to the scalp. Chemical burns are a common occurrence during relaxer application, even with careful technique. These burns can range from mild irritation and redness to severe lesions and scarring.

The scalp, being a highly vascularized area, readily absorbs chemicals. When the skin barrier is compromised by burns or abrasions, the absorption of chemicals from relaxers can increase significantly.

Repeated exposure to these chemicals, often through minor, unnoticed burns, contributes to chronic scalp inflammation. This inflammation is a suspected factor in the development of certain types of hair loss, such as Central Centrifugal Cicatricial Alopecia (CCCA), a progressive form of scarring alopecia that disproportionately affects Black women. Research indicates that the prevalence of CCCA is higher in individuals who have relaxed their hair for more than five years.

Beyond the Strand ❉ Systemic Health Considerations

A more unsettling aspect of relaxer use, and one that has gained significant attention in recent years, concerns the potential for systemic health impacts. Many hair relaxers contain Endocrine-Disrupting Chemicals (EDCs) such as phthalates, parabens, and formaldehyde-releasing agents. These substances, absorbed through the scalp, can interfere with the body’s hormonal balance.

Recent research has brought forth compelling, albeit sometimes controversial, data points linking relaxer use to various health outcomes, particularly among Black women who are the primary consumers of these products. A significant study published in the American Journal of Epidemiology in 2023, part of the Boston University Black Women’s Health Study (BWHS), found that women who reported using hair relaxers had a slight reduction in the likelihood of pregnancy. The study, involving over 11,274 participants, revealed that current and former use of hair relaxers, greater frequency and duration of use, and sustained scalp burns from the products were associated with lower chances of becoming pregnant. This finding underscores the potential for systemic effects beyond direct hair damage, raising questions about reproductive health.

Long-term relaxer use can compromise hair’s natural strength and elasticity, leading to increased fragility and susceptibility to damage.

Furthermore, a 2022 study by the National Institute of Environmental Health Sciences (NIEHS) found that women who frequently used chemical hair straighteners had a higher risk of uterine cancer. Specifically, it was estimated that women who never used hair straighteners would have a 1.64% risk of developing uterine cancer by age 70, but for frequent users, this risk increased to 4.05%. This research, along with other studies linking relaxer use to breast cancer and uterine fibroids, highlights a concerning public health issue that disproportionately affects Black women. The societal pressures to conform to Eurocentric beauty standards have historically driven the widespread use of relaxers, often beginning at young ages, perpetuating a cycle of chemical exposure and potential health risks.

Why are Certain Populations More Affected by Relaxers?

The disproportionate health impacts observed in Black women stem from a confluence of factors. Historically, and even in contemporary contexts, societal pressures have often favored straightened hair textures for perceived professionalism and acceptance. This has led to a higher prevalence and frequency of relaxer use within this demographic, often beginning in childhood.

A study found that 89% of 1,555 African American women reported ever using chemical relaxers, with 96% of those first using them before age 19. This prolonged and frequent exposure to the chemicals, sometimes for decades, contributes to the elevated risks.

Moreover, studies by organizations like the Silent Spring Institute have revealed that a significant percentage of hair products marketed to Black women contain undisclosed hormone-disrupting chemicals, with some products even containing chemicals banned in other countries. This lack of transparency in product labeling further exacerbates the problem, leaving consumers unknowingly exposed to potentially harmful substances. The intersection of cosmetic practices, cultural norms, and regulatory gaps creates a complex landscape of health disparities.

Societal pressures have led to a higher prevalence of relaxer use among Black women, contributing to disproportionate health impacts.

The dialogue surrounding hair relaxers is thus not merely about hair science; it encompasses a deeper societal conversation about beauty standards, health equity, and the systemic factors that influence personal choices. Understanding these intricate layers is essential for a truly comprehensive perspective on how chemical relaxers alter hair structure and, by extension, human well-being.

Reflection

As we step back from the intricate dance of chemistry and keratin, a broader understanding of hair’s resilience and vulnerability comes into view. The journey through the hair shaft’s anatomy, the precise mechanisms of chemical alteration, and the profound, often overlooked, societal and health ramifications of relaxer use, leaves us with a deepened appreciation for the stories our hair can tell. Each strand, whether naturally coiled or chemically smoothed, holds a history of care, choice, and circumstance.

This exploration invites a mindful pause, prompting us to consider not only the visible transformations but also the silent shifts occurring within and around us. The pursuit of beauty, in all its forms, carries a weight of responsibility, a call to seek knowledge and to honor the inherent strength and delicate balance of our being.

References

• Khumalo, N. P. Stone, J. Gumedze, F. McGrath, E. Ngwanya, M. R. & de Berker, D. (2010). ‘Relaxers’ damage hair ❉ Evidence from amino acid analysis. Journal of the American Academy of Dermatology, 62(3), 402-408.
• Khumalo, N. P. & Jessop, S. (2010). The pH of lye and no-lye hair relaxers, including those advertised for children, is at levels that are corrosive to the skin. South African Medical Journal, 100(11), 748-750.
• Díaz, M. & García, M. (2022). Effects of chemical straighteners on the hair shaft and scalp. Anais Brasileiros de Dermatologia, 97(1), 86-96.
• James-Todd, T. et al. (2023). Hair Relaxer Use and Risk of Uterine Leiomyomata ❉ The Black Women’s Health Study. American Journal of Epidemiology.
• James-Todd, T. et al. (2023). Hair Relaxer Use May Affect Ability to Conceive. Boston University School of Public Health.
• Wise, L. A. et al. (2012). Hair relaxer use and risk of uterine leiomyomata in African American women. American Journal of Epidemiology, 175(11), 1132-1140.
• Bertrand, K. et al. (2023). First Large Study of Hair Relaxers Among Black Women Finds Increased Risk of Uterine Cancer. Boston University.
• White, A. J. et al. (2022). Use of Hair Products in Relation to Uterine Cancer Risk. Journal of the National Cancer Institute, 114(12), 1636-1643.
• Chen, Y. et al. (2019). Frequent use of chemical hair straighteners and risk of breast cancer. International Journal of Cancer, 145(5), 1279-1286.
• McDonald, S. (2024). Black Hair Relaxers ❉ Hidden Dangers and Fibroid Connections. Houston Fibroids.
• Swee, W. (2017). Chemical Hair Relaxers Have Adverse Effects ❉ A Myth or Reality. Journal of Clinical and Diagnostic Research, 11(1), WC01-WC04.
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• Cosmetic & Toiletries. (2020). Defying Damage ❉ Understanding Breakage in Afro-textured Hair.
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