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Quizzes > Science > Chemistry

Take the Chemical Texture Services Quiz: Test Your Lanthionization Knowledge!

Ready to master base relaxer definitions and low-pH hair relaxers? Dive in!

Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
Paper art illustration of hair chemistry quiz elements lanthionization base relaxer icons on coral background

Use this quiz to practice lanthionization basics - what it is, how hydroxide relaxers create it, and what "base relaxer" means. Get quick feedback to check gaps before an exam or salon service, and review with our chemical texture study guide today.

What is lanthionization?
Hydrolyzing the hair cortex
Breaking keratin proteins into peptides
Oxidizing hair cuticle layers
Conversion of disulfide bonds into lanthionine bonds
Lanthionization is the chemical process that converts disulfide bonds in keratin into stable thioether bonds called lanthionine. This modification is irreversible and changes hair texture permanently. It occurs during certain chemical relaxer treatments where disulfide bonds are reduced and rearranged. For more details see .
What component in a base relaxer protects the scalp?
Thio relaxer cream
Base cream barrier
Neutralizing shampoo
Oxidizing lotion
A base relaxer includes a protective base cream that shields the scalp from the high alkalinity of the relaxer solution. The barrier cream prevents chemical burns and irritation during processing. It is applied along the hairline and scalp before the relaxer is combed through. For more information see .
Which bond is targeted by most chemical relaxers?
Disulfide bonds
Hydrogen bonds
Ionic bonds
Peptide bonds
Chemical relaxers primarily target the disulfide bonds in the keratin structure of hair. Breaking these bonds allows the hair to be reshaped and straightened. After reshaping, the bonds are reformed or altered to hold the new texture. Read more at .
Typical pH range of a hydroxide relaxer?
12-14
7-8
9-10
5-6
Hydroxide relaxers are extremely alkaline, with pH values typically between 12 and 14. The high pH raises the hair cuticle and breaks disulfide bonds efficiently. This strong alkalinity also requires protective measures to avoid scalp irritation. Learn more at .
Which amino acid is directly involved in forming disulfide bonds in hair?
Lysine
Glycine
Methionine
Cysteine
Cysteine contains a thiol group that forms disulfide bonds with another cysteine residue, creating cystine linkages. These covalent bonds are critical to hair's strength and elasticity. Chemical treatments often target these bonds to alter texture. For details see .
Which hair layer is most affected by chemical relaxers?
Medulla
Cuticle
Cortex
Follicle
Chemical relaxers penetrate the cuticle to reach the cortex, where the majority of disulfide bonds are located. The cortex is responsible for hair's strength, elasticity, and structure. Altering the bonds in this layer changes the hair's texture permanently. For more see .
What type of bond is formed as a result of lanthionization?
Hydrogen bond
Disulfide bond
Thioether bond
Salt link
During lanthionization, the original disulfide bond is reduced and reconnected as a thioether (lanthionine) linkage. This thioether bond is more stable and cannot be reoxidized back to a disulfide. It permanently alters hair texture. More information at .
Which chemical is not typically used in the lanthionization process?
Sodium hydroxide
Thioglycolate
Ammonium thioglycolate
Cysteamine
Lanthionization involves thiol-containing agents like thioglycolates and cysteamine, which reduce disulfide bonds. Sodium hydroxide is used in hydroxide relaxers but does not cause lanthionine bond formation. It acts as a strong alkali to break bonds hydrolytically. See https://www.cosmeticsandtoiletries.com/formulating/function/conditioning/article/21842854/relaxers-chemistry-constraints-and-advances.
What distinguishes a no-lye relaxer from a lye relaxer?
Lye uses guanidine hydroxide
Lye uses ammonium thioglycolate
No-lye uses ammonium thioglycolate
No-lye uses guanidine hydroxide
No-lye relaxers typically use guanidine hydroxide, formed by combining guanidine carbonate and calcium hydroxide. Lye relaxers use sodium hydroxide as the active alkalizing agent. The different chemistries affect speed and scalp comfort. More details at .
Before applying a base relaxer, what protective step is taken?
Oil scalp with protective cream
Pre-shampoo twice
Dampen hair fully
Apply oxidizing spray
Styling professionals apply a protective barrier cream or oil to the scalp and hairline before a base relaxer. This barrier shields skin from the high-pH solution, preventing burns. Proper application ensures safety and comfort. Read more at .
Which product helps rebuild disulfide bonds after a relaxer service?
Protein filler
Deep conditioner
Clarifying shampoo
Bond rebuilder with bis-aminopropyl diglycol dimaleate
Bond rebuilders containing bis-aminopropyl diglycol dimaleate penetrate the cortex to reform or fortify broken disulfide links. They selectively link free thiols back together, restoring strength. Regular conditioners do not perform this chemical function. See .
Keratin's alpha-helix structure is disrupted by which agent?
Random coil
Triple helix
Alpha-helix coil
Beta-keratin
Keratin in hair adopts an alpha-helix structure stabilized by hydrogen bonds and disulfide linkages. Reducing agents like thioglycolate break these bonds, disrupting the alpha-helix. This allows reshaping during perms or relaxers. Details at .
Which is the correct sequence in chemical texturizing?
Rinse, saturate, neutralize
Saturate, neutralize, rinse
Neutralize, saturate, rinse
Relax, neutralize, cleanse
First the hair is saturated with reducer (perm or relaxer), then neutralized to reform bonds, and finally rinsed to remove all chemicals. Any deviation can lead to incomplete processing or damage. This sequence is industry standard. Learn more at .
Why is neutralization essential after perming or relaxing?
Breaks residual thioethers
Reforms disulfide bonds
Strengthens alkaline pH
Removes excess water
Neutralization oxidizes the reduced thiol groups back into stable disulfide bonds, locking in the new shape or texture. Without this step, hair remains weak and prone to breakage. It also brings pH back to a safe level for the hair and scalp. See .
Which compound is commonly used in no-lye hair relaxers?
Guanidine hydroxide
Sodium bromate
Lithium hydroxide
Ammonium thioglycolate
No-lye relaxers often use guanidine hydroxide, formed in situ from guanidine carbonate and calcium hydroxide. It relaxes hair by raising pH and cleaving disulfide bonds without sodium hydroxide. This formula is gentler on the scalp. For more information see .
During lanthionization, how does the pH of the solution behave?
Fluctuates between acidic and alkaline
Drops to acidic
Remains highly alkaline
Stays neutral throughout
Lanthionization requires a strongly alkaline environment to reduce disulfide bonds effectively. The pH generally remains high until neutralization. Maintaining alkalinity ensures efficient thioether bond formation. See .
Thioether bond formation in lanthionization involves which nucleophile?
Thiolate anion
Hydride ion
Hydroxide ion
Ammonia
The thiolate anion generated under alkaline conditions attacks the disulfide bond to form a thioether (lanthionine) crosslink. This nucleophilic attack is essential for irreversible bond conversion. Understanding this step clarifies why a high pH is necessary. More at .
What is the primary difference in disulfide cleavage between perms and relaxers?
Both use reduction
Relaxers use oxidation
Perms use reduction
Both use oxidation
Perm solutions use reducing agents (thioglycolates) to break disulfide bonds gently for curl formation. Many relaxers use strong alkali (hydroxides) that hydrolyze the bonds more aggressively. The mechanisms differ in their chemistry and outcome. For details see .
Lanthionine is best described as:
A thioether link formed from two cysteines
A three-amino-acid peptide
A thioether crosslink of two alanines
An oxidized methionine derivative
Lanthionine is formed when two cysteine residues lose a sulfur atom and form a thioether bond, linking their alpha carbons. This crosslink replaces the original disulfide (cystine) bond irreversibly. It is not a peptide but an amino acid-derived linkage. More information at .
Which oxidizing agent is typically used during neutralization of a perm or relaxer?
Hydrogen peroxide
Sodium hypochlorite
Sodium bromate
Ammonium persulfate
Hydrogen peroxide is commonly used to oxidize reduced thiol groups back into disulfide bonds during neutralization. It stabilizes the new hair structure and halts the reducing action. Other oxidizers are less common in salon chemistry. Read more at .
What does a mercaptan test detect in treated hair?
Thioether bonds
pH level
Hydrogen bonds
Tensile strength
A mercaptan (thiol) test detects free sulfhydryl groups remaining after treatment. The presence of mercaptans indicates incomplete oxidation or neutralization. It is used to ensure proper reforming of disulfide bonds. More at .
Why are buffers added to relaxer formulations?
To add fragrance
To increase relaxer strength
To stabilize pH
To enhance color
Buffers help maintain a consistent pH during the chemical reaction, ensuring predictable bond cleavage and preventing pH spikes that can damage hair or scalp. They balance the alkalinity provided by the active agent. Stable pH improves safety and efficacy. See .
Excessive chemical processing can convert cystine into which irreversible form?
Keratinase
Cysteic acid
Lysine
Methionine
Overprocessing can oxidize cystine beyond disulfide cleavage into cysteic acid, which cannot reform disulfide bonds. This leads to permanent weakening and porosity. Cysteic acid formation is a marker of damage. For more see .
Increased hair porosity after lanthionization is due to:
Increased spacing from thioether crosslinks
Residual oil coating
Cuticle dehydration
Protein deposition
Lanthionization replaces compact disulfide bonds with longer thioether linkages, increasing the spacing between keratin chains. This increases the free volume and porosity of the cortex. More porous hair absorbs moisture differently and feels drier. See .
In thiol/disulfide exchange kinetics during lanthionization, which step is rate-determining?
Nucleophilic attack by thiolate anion
Protonation of disulfide bonds
Disulfide cleavage by hydrogen peroxide
Peptide backbone hydrolysis
The nucleophilic attack by the thiolate anion on the disulfide bond is the slowest, rate-determining step in thiol/disulfide exchange. It requires proper alignment and high pH to generate the active nucleophile. Understanding this helps improve reaction control. More at .
Compared to native hair, the tensile strength of lanthionized hair is approximately:
90% (near native strength)
50 - 70% of original strength
30 - 40% of original strength
Over 100% (stronger than native)
Studies show lanthionized hair retains about 50 - 70% of the tensile strength of untreated hair due to irreversible thioether bonds being less flexible. The loss reflects partial structural compromise. These values guide safe formulation. See .
Which analytical method is most precise for quantifying lanthionine versus cystine in hair samples?
pH titration
Mass spectrometry
FTIR spectroscopy
Gel electrophoresis
Mass spectrometry paired with amino acid analysis provides precise quantitation of lanthionine and cystine levels. It distinguishes mass differences between thioether and disulfide-linked residues. Other methods lack this specificity. For details see .
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Study Outcomes

  1. Define Lanthionization -

    Readers will be able to explain what is lanthionization, detailing the chemical conversion of cystine bonds into lanthionine bonds in hair.

  2. Identify Hydroxide Relaxer Treatments -

    Readers will recognize hair that is treated with hydroxide relaxers and describe its structural and cosmetic characteristics.

  3. Explain Sulfite Compatibility -

    Readers will understand the sulfites used as low-pH hair relaxers are compatible with hair proteins and scalp chemistry.

  4. Clarify Base Relaxer Concepts -

    Readers will articulate the base relaxer definition cosmetology and its application in professional hair texture services.

  5. Differentiate Relaxer Types -

    Readers will compare lanthionization to other relaxer systems, highlighting pH levels and processing requirements.

  6. Apply Quiz Insights -

    Readers will apply their knowledge in a quiz format to reinforce understanding of low-pH hair relaxers and chemical texture treatments.

Cheat Sheet

  1. What is Lanthionization? -

    Lanthionization is the chemical conversion of cystine disulfide bonds into lanthionine by replacing one sulfur atom, permanently restructuring the hair's keratin network. For example, R - S - S - R + 2 OH - → R - S - CH2 - CH2 - CH2 - S - R in a basic environment illustrates this transformation. Use the mnemonic "Lan-thi-one less S" to remember that lanthionine contains one fewer sulfur than cystine (J. Soc. Cosm. Chem, 1978).

  2. Mechanism of Hydroxide Relaxers -

    Hydroxide relaxers, such as sodium or potassium hydroxide, elevate pH above 12 to cleave disulfide bonds and enable lanthionization of hair that is treated with hydroxide relaxers. Once bonds break, the hair cannot re-form cystine links, making the change permanent. Research from the International Journal of Cosmetic Science explains how concentration and application time control relaxation strength.

  3. Base Relaxer Definition in Cosmetology -

    In cosmetology, a base relaxer definition cosmetology describes a chemical relaxer applied with a protective base cream on the scalp to prevent irritation. Base relaxers differ from no-lye formulas by requiring this barrier and often deliver a smoother application. Milady's Standard Cosmetology text details the protocol for base application and timing.

  4. Characteristics of Hair Treated with Hydroxide Relaxers -

    Hair that is treated with hydroxide relaxers exhibits permanently broken disulfide bonds and compromised elasticity due to lanthionine formation. Its lanthionized structure has reduced tensile strength and can feel coarser or more porous. The University of Minnesota Extension notes that proper neutralization and conditioning are critical to minimize damage.

  5. Sulfites in Low-pH Hair Relaxers -

    The sulfites used as low-pH hair relaxers are compatible with acid-balanced shampoos and color-treated hair, operating effectively around pH 6 - 7. Ammonium bisulfite and ammonium sulfite relaxers offer gentle reduction of disulfide bonds without extreme alkalinity. According to the International Hair Journal, these low-pH systems reduce scalp irritation and maintain hair integrity.

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