75 questions · 75 min · 75% to pass
Question 1
How does hyaluronic acid attract and retain moisture in the skin?
Answer: Hyaluronic acid is a glycosaminoglycan capable of binding up to 1,000 times its own weight in water through hydrogen bonding with water molecules. This extraordinary hygroscopic capacity allows it to hydrate the extracellular matrix and maintain skin plumpness and elasticity.
Question 2
Which type of contact reaction requires prior sensitization to occur?
Answer: Allergic contact reaction
Question 3
What AHA concentration is used in professional peels?
Answer: 20–70%
Question 4
What advantage does zinc oxide have over titanium dioxide in terms of UV spectrum coverage?
Answer: Zinc oxide provides broader spectrum coverage than titanium dioxide, effectively blocking both UVA1 (340–400 nm) and UVA2 rays in addition to UVB. Titanium dioxide offers excellent UVB and some UVA2 protection but is less effective against longer UVA1 wavelengths.
Question 5
How do palmitoyl peptides such as palmitoyl tripeptide-1 claim to stimulate collagen production in the skin?
Answer: Palmitoyl peptides mimic fragments of collagen that are naturally produced during its breakdown, signaling fibroblasts to increase collagen synthesis as part of the wound-healing response. The palmitoyl (fatty acid) chain attached to the peptide improves its ability to penetrate the lipid-rich skin barrier.
Question 6
How many conversion steps does retinol need to become active?
Answer: Two conversion steps
Question 7
Why is avobenzone often paired with stabilizing ingredients like octocrylene in sunscreen formulations?
Answer: Avobenzone is inherently photounstable and breaks down rapidly when exposed to UV light, losing up to 50–90% of its protective efficacy within an hour of sun exposure. Octocrylene and other stabilizers absorb the energy that would otherwise degrade avobenzone, preserving broad-spectrum UVA protection.
Question 8
Why are parabens used as preservatives in cosmetics, and what is the primary safety concern associated with them?
Answer: Parabens are broad-spectrum antimicrobial preservatives that prevent bacterial and fungal growth in cosmetic formulations, extending shelf life and preventing infections. The primary safety concern is that some parabens, particularly butylparaben and propylparaben, have demonstrated weak estrogenic activity in laboratory studies, raising potential endocrine disruption concerns.
Question 9
At what concentration is salicylic acid recognized as an OTC drug by the FDA for acne treatment?
Answer: The FDA recognizes salicylic acid as an OTC acne-treatment drug at concentrations between 0.5% and 2%. Products within this range can make acne-treatment claims, while higher concentrations require professional application due to increased risk of skin damage.
Question 10
Why is salicylic acid effective for acne-prone skin?
Answer: It is oil-soluble and penetrates pores