NIC Esthetician Written ExamScientific ConceptsMedium
A cosmetic chemist is formulating a new serum designed to improve skin hydration and reduce transepidermal water loss (TEWL). Which class of ingredients would be most effective in forming an occlusive barrier on the skin's surface to achieve these goals?
- AEmollients
- BAntioxidants
- COcclusives
- DHumectants
Show answer & explanationAnswer & explanation
Correct answer: C. Occlusives
Occlusive ingredients form a physical barrier on the skin's surface, preventing water from evaporating (reducing TEWL) and thus locking in moisture, which directly addresses the goal of improving skin hydration.
Why the other options are wrong
- A. Emollients smooth and soften the skin by filling gaps between skin cells, but their primary function is not to form an occlusive barrier.
- B. Antioxidants protect against free radical damage and inflammation but do not directly impact TEWL or hydration through barrier formation.
- D. Humectants attract water from the air or deeper skin layers, but do not primarily form a barrier to prevent water loss.
Occlusive Ingredients
Substances that form a protective layer on the skin's surface, preventing water evaporation and reducing transepidermal water loss (TEWL).
- Create a physical barrier
- Reduce TEWL
- Examples: petroleum jelly, mineral oil, silicones
Memory trick: Occlusives are like a 'lock' for moisture.