10/09/2025
pH Scale Quiz Q Answered
Today's Barber Theory Exam Style Question (in the Domain of Scientific Concepts – 35%)
Question:
Which of the following describes the pH level of healthy hair and scalp?
A. 2.0 to 3.0
B. 4.5 to 5.5
C. 6.5 to 7.5
D. 8.0 to 9.0
Correct answer is B, 4.5 to 5.5
⚗️ What Is pH?
pH stands for potential hydrogen, and it measures how acidic or alkaline a substance is on a scale from 0 to 14.
0–6.9 = Acidic
7 = Neutral
7.1–14 = Alkaline
💈 pH of Healthy Hair and Scalp
The ideal pH range for both hair and scalp is 4.5 to 5.5.
This slightly acidic level helps maintain the acid mantle, a natural barrier made up of sebum (oil) and sweat that:
Protects against bacteria and fungi
Keeps the cuticle layer smooth and compact
Prevents excessive dryness or oiliness
🧬 Why It Matters in Barbering
Chemical Balance – Chemical services (like relaxers, perms, or coloring) temporarily raise the hair’s pH, causing the cuticle to open. Returning it to an acidic level helps close and seal the cuticle afterward.
Product Selection – Using products formulated within the 4.5–5.5 pH range helps preserve the hair’s natural condition and scalp health.
Scalp Health – A disrupted pH can lead to dandruff, dryness, or irritation if the scalp becomes too alkaline, or excess oil production if it becomes too acidic.
🧴 Quick Barber Tip
After chemical services, acid-balanced shampoos or conditioners should be used to restore the hair and scalp back to the natural 4.5–5.5 range — this keeps hair strong, shiny, and manageable.
