What is the main active ingredient in true acid and acid-balanced waving lotions?

• A. Ammonium thioglycolate
• B. Glyceryl monothioglycolate
• C. Sodium hydroxide
• D. Hydrogen peroxide

Answer: (B)

Verified step by step guidance

1. Understand the context of the question: The problem is asking about the main active ingredient in true acid and acid-balanced waving lotions, which are used in hair treatments to break and reform disulfide bonds in keratin.
2. Recall the key chemical used in acid-balanced waving lotions: Glyceryl monothioglycolate (GMTG) is the primary active ingredient in these products. It is a derivative of thioglycolic acid and is less alkaline than ammonium thioglycolate, making it suitable for acid-balanced formulations.
3. Differentiate between the options provided: Ammonium thioglycolate is used in alkaline waving lotions, while glyceryl monothioglycolate is specific to acid-balanced waving lotions. Sodium hydroxide and hydrogen peroxide are not relevant to this specific application.
4. Understand the role of glyceryl monothioglycolate: It works by breaking the disulfide bonds in keratin, allowing the hair to be reshaped. The 'acid-balanced' nature refers to a pH closer to the natural pH of hair and skin, typically around 4.5 to 7.
5. Conclude the reasoning: Based on the chemical properties and the application, the correct answer is glyceryl monothioglycolate, as it is specifically formulated for true acid and acid-balanced waving lotions.