This problem set is the definitive guide for those aiming to pass the Cosmetics Ingredient Certification Level 1 exam, featuring a carefully selected 200 questions. Detailed answer explanations are provided for all questions, based on evidence required in the field of raw material manufacturers and formulation development, allowing you to cultivate the skills of an "ingredient specialist" with practical application abilities. ■ Contents of this book • Chapter 1: Formulation Design and Pharmaceutics (Questions 1-40) Advanced formulation techniques such as emulsification (O/W, W/O) mechanisms, solubilization, dispersion, HLB value calculation, liquid crystal structure, and D-phase emulsification. • Chapters 2-3: Application of Oil-based Ingredients and Surfactants (Questions 41-95) Polarity and compatibility of ester oils, silicone network structure, high molecular weight surfactants, and detailed property comparisons of amino acid-based cleansing ingredients. • Chapter 4: Details of Functional Ingredients (Questions 96-130) Mechanisms of action of niacinamide and retinol, stabilization techniques for vitamin C derivatives, and penetration routes into the stratum corneum (percutaneous absorption). • Chapter 5: Formulation by Product Type (Questions 131-170) Solidification mechanism of cleansing balms, feel adjustment of non-silicone shampoos, and anti-white cast technology for sunscreens. • Chapters 6-7: Safety, Regulations, and Comprehensive Questions (Questions 171-200) Labeling rules for quasi-drugs, safety tests such as patch tests and RIPT, and analysis of product concepts by reading the full ingredient list. ■ Features of this book • Deep explanation of "formulation logic" Based on evidence from a pharmaceutics perspective, it details why this ingredient is formulated in this order, synergistic effects between ingredients, and stabilization techniques. • Addresses "difficult questions unique to Level 1" It is structured to allow efficient memorization of even the most detailed knowledge frequently tested in Level 1, such as "the two approved efficacies that niacinamide uniquely possesses," along with background knowledge. • Includes "practical case studies" It cultivates problem-solving skills that can be used directly in the field, such as ingredient proposals tailored to specific skin concerns and identifying the causes of sensory issues (stickiness, separation).