Esthetician Practice Exam Esthetician Practice Chemistry and Product Ingredients 1 — Questions and Answers
Question 1: Which of the following best describes the mechanism of action of alpha hydroxy acids (AHAs) on the skin?
- They neutralize free radicals by donating electrons to unstable molecules
- They loosen the bonds between corneocytes, promoting exfoliation of dead skin cells (Correct answer)
- They stimulate melanin production in the basal layer of the epidermis
- They cross-link collagen fibers to increase skin firmness
Correct answer: They loosen the bonds between corneocytes, promoting exfoliation of dead skin cells
AHAs such as glycolic and lactic acid work by weakening the intercellular adhesion between corneocytes (dead skin cells) in the stratum corneum, facilitating their shedding and revealing smoother, brighter skin underneath.
Question 2: What is the primary role of emollients in a skincare formulation?
- To kill bacteria on the skin surface through antimicrobial action
- To draw water from the dermis into the epidermis
- To fill gaps between skin cells and smooth the skin's surface (Correct answer)
- To lower the pH of a product to improve active ingredient penetration
Correct answer: To fill gaps between skin cells and smooth the skin's surface
Emollients such as squalane, shea butter, and fatty acids fill in the spaces between skin cells, creating a smoother surface texture and improving skin suppleness by preventing water from escaping.
Question 3: Which preservative system is most commonly used in natural or 'clean beauty' formulations as an alternative to parabens?
- Phenoxyethanol (Correct answer)
- Methylparaben
- Formaldehyde releasers
- Sodium lauryl sulfate
Correct answer: Phenoxyethanol
Phenoxyethanol is a widely accepted preservative in natural and clean beauty formulations because it is considered safer and less controversial than parabens or formaldehyde-releasing preservatives, while still providing effective broad-spectrum antimicrobial protection.
Question 4: Niacinamide (Vitamin B3) is valued in skincare primarily because it:
- Acts as a chemical exfoliant by dissolving the skin's lipid barrier
- Inhibits the transfer of melanosomes from melanocytes to keratinocytes (Correct answer)
- Increases transepidermal water loss to improve cell turnover
- Functions as a UV filter by absorbing ultraviolet radiation
Correct answer: Inhibits the transfer of melanosomes from melanocytes to keratinocytes
Niacinamide reduces hyperpigmentation and uneven skin tone by interfering with the transfer of melanin-containing melanosomes from pigment-producing melanocytes to surrounding keratinocytes, without affecting melanin synthesis itself.
Question 5: Which of the following ingredient categories functions as a humectant?
- Cetyl alcohol
- Glycerin (Correct answer)
- Dimethicone
- Titanium dioxide
Correct answer: Glycerin
Glycerin is a classic humectant — it attracts and binds water molecules from the environment and deeper skin layers to the stratum corneum, helping to maintain skin hydration. Cetyl alcohol is an emollient, dimethicone is an occlusive, and titanium dioxide is a physical sunscreen.
Question 6: A formulator wants to create an oil-in-water (O/W) emulsion. Which of the following emulsifiers would be most appropriate?
- An emulsifier with a low HLB value (3–6)
- An emulsifier with a high HLB value (8–18) (Correct answer)
- A purely hydrophobic wax such as carnauba wax
- A silicone-based occlusive agent
Correct answer: An emulsifier with a high HLB value (8–18)
HLB (Hydrophilic-Lipophilic Balance) values indicate an emulsifier's affinity for water versus oil. Emulsifiers with high HLB values (8–18) are more hydrophilic and stabilize oil-in-water emulsions, while low HLB emulsifiers (3–6) are better suited for water-in-oil emulsions.
Esthetician Practice Exam Esthetician Practice Chemistry and Product Ingredients 1
Which of the following best describes the mechanism of action of alpha hydroxy acids (AHAs) on the skin?