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Cosmetology Practice Test

Most Missed Cosmetology Questions

These are the Cosmetology practice questions that people on Tigertest get wrong most often, from the answers of 7 people. Each one shows the share who missed it, the right answer and why.

Updated by the Tigertest team. These sets follow the NIC theory exam only: 110 items, 100 scored, 90 minutes (outline effective July 1, 2022). PSI states, including California from April 1, 2026, use a 120-minute outline. This bank is not weighted to PSI.

  1. 64% of people missed this (22 answers)

    1. The chemical process that breaks disulfide bonds during a perm is:

    • A.Neutralization
    • B.Reduction
    • C.Hydrolysis
    • D.Oxidation

    Answer: B. Thioglycolate adds hydrogen to the disulfide bond, which is a reduction reaction. The neutralizer later oxidizes the hair to rebuild the bonds.

  2. 47% of people missed this (17 answers)

    2. A shampoo for chemically treated hair should have a pH that is:

    • A.Neutral at 7
    • B.Strongly acidic
    • C.Mildly alkaline
    • D.Slightly acidic

    Answer: D. Hair and skin sit at a pH of about 4.5 to 5.5, so a slightly acidic shampoo closes the cuticle and protects color and texture services. Alkaline shampoos swell the hair and strip color.

  3. 50% of people missed this (16 answers)

    3. The most common neutralizer in permanent waving is:

    • A.Hydrogen peroxide
    • B.Ammonium hydroxide
    • C.Thioglycolic acid
    • D.Sodium hydroxide

    Answer: A. Most neutralizers are hydrogen peroxide, which removes the added hydrogen and reforms the disulfide bonds in their new position. Sodium bromate is a less common alternative.

  4. 41% of people missed this (17 answers)

    4. Red, swollen, painful tissue around the nail fold is called:

    • A.Leukonychia
    • B.Onychorrhexis
    • C.Paronychia
    • D.Onychophagy

    Answer: C. Paronychia is a bacterial infection of the skin around the nail, common in people whose hands are often wet. Onychophagy is nail biting and onychorrhexis is split, brittle nails.

  5. 38% of people missed this (16 answers)

    5. White spots in the nail plate are known as:

    • A.Onycholysis
    • B.Koilonychia
    • C.Leukonychia
    • D.Melanonychia

    Answer: C. Leukonychia spots usually come from minor injury to the matrix and grow out harmlessly. Melanonychia is a dark band and koilonychia is a spoon-shaped nail.

Tigertest tracks the 50 most-missed Cosmetology questions. These are the top 5; the full list is the Common Mistakes tab of your stats page.

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