Lesson 1Humectants: examples (glycerin, propanediol, sodium PCA), mechanism and suitability for sensitive skinThis part looks at humectants like glycerin, propanediol, and sodium PCA, explaining water-holding ways, blend teamwork, skin feel effect, and tailoring for sensitive or weak barriers.
Glycerin: benchmark humectant behaviorPropanediol and alternative glycolsSodium PCA and NMF-mimicking blendsTack reduction and sensory balancingHumectants in barrier-impaired skinLesson 2Antioxidants and chelators: examples (tocopherol, EDTA), role in oxidative stability and preservationThis part explains how antioxidants and chelators like tocopherol and EDTA guard oils and actives from oxidation, aid preservative setups, and lengthen shelf life without harming skin comfort or clearness.
Lipid-phase antioxidants for oilsWater-phase antioxidants and synergyChelators to control trace metalsImpact on color and odor stabilityDesigning antioxidant systems in O/WLesson 3Occlusives: examples (dimethicone, hydrogenated polyisobutene), balancing occlusion and light feelThis part discusses occlusives like dimethicone and hydrogenated polyisobutene, showing balance of barrier strength, water loss cut, and light, airy feel for daily sensitive skin care.
Dimethicone grades and skin feelHydrogenated polyisobutene in creamsTEWL reduction and barrier metricsAvoiding heaviness and pore occlusionOcclusive levels for day versus nightLesson 4Soothing/anti-irritant actives: examples (niacinamide, panthenol, dipotassium glycyrrhizate), evidence and typical use rangesThis part checks soothing and anti-irritant actives like niacinamide, panthenol, and dipotassium glycyrrhizate, summing ways, proof, fit, and usual ranges in sensitive skin moisturizers.
Niacinamide: barrier and redness benefitsPanthenol: hydration and repair rolesDipotassium glycyrrhizate: calming actionUse levels and pH compatibilityCombining soothing actives safelyLesson 5Core functional groups for O/W moisturizer: role of solvent, humectant, emollient, occlusive, emulsifierThis part maps main functional groups in O/W moisturizers—solvents, humectants, emollients, occlusives, emulsifiers—showing each's part in feel, hydration, stability, and tolerance for sensitive skin.
Water phase and co-solvent selectionHumectant blend design and levelsEmollient phase structure and feelOcclusive agents and barrier supportEmulsifier system and phase balanceLesson 6Preservative systems for mild formulas: examples (phenoxyethanol+ethylexylglycerin, sodium benzoate+potassium sorbate), rationale for sensitive skinThis part reviews preservative setups for mild O/W moisturizers, like phenoxyethanol with ethylhexylglycerin and acid salts, focusing on coverage, pH needs, rule limits, and sensitive skin fit.
Phenoxyethanol and boosters in blendsSodium benzoate and potassium sorbatepH windows for organic acid systemsPreservative efficacy versus mildnessMinimizing sting and sensitization riskLesson 7Emollients: examples (caprylic/capric triglyceride, C12-15 alkyl benzoate), sensory and absorption considerationsThis part explores emollient picks like caprylic/capric triglyceride and C12-15 alkyl benzoate, tying structure to spread, absorb speed, leftover, and fit for light, non-oily sensitive skin creams.
Medium-spreading esters and triglyceridesFast-absorbing versus rich emollientsPolarity and pigment or filter wettingTack, gloss, and afterfeel controlEmollient choices for acne-prone skinLesson 8Solubilizers, pH adjusters, and texture modifiers: examples and impact on performanceThis part reviews key solubilizers, pH tuners, and texture changers in O/W moisturizers, explaining effects on clearness, thickness, spread ease, and overall work while keeping sensitive skin comfort.
Nonionic solubilizers for fragrance and oilspH adjustment for skin compatibilityBuffers and pH drift controlRheology modifiers and viscosity tuningSlip, spread, and pick-up optimizationLesson 9Common incompatibilities and ingredient substitution strategiesThis part covers usual mismatches in O/W moisturizers, like pH, charge, oxidation problems, and gives real swap plans to keep stability, mildness, and work when changing suppliers or actives.
pH-driven instability and hydrolysisCationic–anionic charge conflictsOxidation-prone oils and activesPreservative and polymer conflictsDesigning robust substitution plansLesson 10Emulsifiers and co-emulsifiers: examples (polyglyceryl esters, glyceryl stearate SE), HLB considerations and mildnessThis part details emulsifiers and co-emulsifiers like polyglyceryl esters and glyceryl stearate SE, explaining HLB ideas, needed HLB of oil parts, and designing mild, stable setups for sensitive skin moisturizers.
Required HLB of the oil phaseNonionic emulsifiers for mildnessPolyglyceryl esters in O/W systemsFatty alcohols as co-emulsifiersOptimizing droplet size and stability
