Texas Cosmetology Operator Written ExamChemistryMedium
A client presents with extremely dry, brittle hair. The cosmetologist suspects the client has been using products that are too alkaline. What is the approximate pH of human hair and skin, which is considered the 'acid mantle' and helps protect against bacteria and environmental damage?
- ApH 8.5 (Alkaline)
- BpH 2.0-3.0 (Strongly acidic)
- CpH 7.0 (Neutral)
- DpH 4.5-5.5 (Slightly acidic)
Show answer & explanationAnswer & explanation
Correct answer: D. pH 4.5-5.5 (Slightly acidic)
The natural pH of human hair and skin is slightly acidic, typically ranging from 4.5 to 5.5. This 'acid mantle' is crucial for protecting the skin and hair from bacterial growth and maintaining integrity.
Why the other options are wrong
- A. An alkaline pH like 8.5 would strip the acid mantle, causing dryness and brittleness, not represent the healthy state.
- B. A strongly acidic pH like 2.0-3.0 would be too harsh and damaging to hair and skin.
- C. A neutral pH of 7.0 is not the natural state of healthy hair and skin.
Acid Mantle
A very fine, slightly acidic film on the surface of human skin and hair, acting as a barrier to bacteria, viruses, and other potential contaminants.
- Natural pH 4.5-5.5
- Protects skin and hair
- Disrupted by alkaline products
Memory trick: Four-Five is Fine, Five-Five for Skin and Shine.