Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceDive into soothing and barrier-fixing actives good for sensitive, dehydrated skin. Learn how dem work and use levels for panthenol, niacinamide, ceramides, cholesterol, fatty acids, and oat extracts in simple formulas.
Panthenol for soothing and barrier recoveryNiacinamide at low, tolerable inclusion levelsCeramide, cholesterol, fatty acid ratiosColloidal oatmeal and oat-derived activesCombining actives without overloading skinLesson 2Design principles for sensitive-dehydrated skin: minimalism, low-irritancy, barrier-supporting, humectant-emollient balanceDefine main design principles for sensitive, dehydrated skin: keeping it simple, low irritation, and barrier support. Learn to limit actives, avoid repeats, and balance humectants with emollients in a straightforward routine.
Minimalist INCI lists and formula focusAvoiding common irritant and sensitizer groupsHumectant–emollient–occlusive balancingLayering strategy across a simple routinePatch testing and gradual introductionLesson 3Humectants, occlusives, and emollients: glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with suggested use-level rangesUnderstand how humectants, occlusives, and emollients team up to hydrate sensitive, dehydrated skin. Review glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with practical use ranges.
Water-binding humectants and optimal levelsHyaluronic acid types and molecular weightsLight emollients: squalane and estersFatty alcohols for structure and mildnessBalancing humectant load to avoid tightnessLesson 4pH targeting and buffer systems: safe pH ranges for skin, stability considerations, and ingredient compatibilityLearn to aim for skin-friendly pH ranges and make buffer systems that protect skin and formula. Address compatibility with actives, surfactants, and preservatives, and watch pH changes over time.
Physiological pH range and barrier impactpH needs of surfactants and preservativesSelecting acids, bases, and buffersManaging pH drift during stability testspH considerations for exfoliating activesLesson 5Preservative approaches suitable for sensitive skin: approved preservative families, typical levels, synergists, and preservative-free risk managementReview preservative systems good for sensitive formulas. Compare approved types, usual levels, and boosters, and understand risks and controls when going preservative-free.
Regulatory status of key preservative groupsOrganic acids and mild preservative blendsChelators and humectants as boostersChallenge testing and PET requirementsRisk of under-preservation and recallsLesson 6Fragrance and allergen strategy: fragrance-free vs masked scents, IFRA considerations, and EU/allergen declarationDevelop a fragrance and allergen plan good for sensitive skin. Compare no-fragrance, essential oils, and low-allergen mixes, apply IFRA limits, and handle EU-style allergen labeling and consumer expectations.
Fragrance-free versus low-scent approachesEssential oils and sensitization riskUsing IFRA categories and maximum levelsLabeling listed fragrance allergensMasking base odors without overloadingLesson 7Gentle surfactants and mild cleansing systems: non-ionic/amine oxide/zwitterionic options and concentration guidanceLearn to pick ultra-mild surfactant systems for cleansers targeting sensitive, dehydrated skin. Compare nonionic, amine oxide, and zwitterionic options, set safe levels, and design low-foam, low-irritancy bases.
Irritation mechanisms of common surfactantsNonionic surfactants for sensitive skinAmine oxides and zwitterionic co-surfactantsDesigning low-foam, creamy cleanser basesActive surfactant level and dilution guidanceLesson 8Ingredient selection framework: prioritizing safety, evidence, and multifunctional activesBuild an ingredient picking framework that put safety, evidence, and multi-use first. Learn to read safety data, weigh in vivo and in vitro support, and choose ingredients that give several benefits at once.
Reading safety assessments and CIR opinionsEvaluating clinical and instrumental dataChoosing multifunctional emollient-humectantsSupplier documentation and quality checksDecision trees for go or no-go ingredientsLesson 9Formulation rheology and sensorial design: emulsion types (O/W, water-serum, gel-cream), viscosity modifiers, and sensory targets for a minimalist lineMaster rheology and sensorial design for simple systems. Compare O/W creams, water-serums, and gel-creams, pick viscosity modifiers, and adjust slip, playtime, and afterfeel for fragile, easily overloaded skin.
Choosing emulsion type for skin conditionPolymeric versus natural thickenersSlip, playtime, and afterfeel optimizationLightweight gel-creams for dehydrationStability checks for low-oil systemsLesson 10Skin physiology and pathophysiology: barrier function, TEWL, sensitive skin triggers, and dehydration vs drynessExplore how weak barriers, TEWL, and nerve overreactivity define sensitive, dehydrated skin. Learn main triggers, how dehydration different from dryness, and what it mean for picking textures, actives, and surfactant systems.
Stratum corneum structure and lipid organizationTEWL, corneometry, and hydration assessmentNeurosensory hyperreactivity and stingingTriggers: surfactants, pH, fragrance, alcoholsDehydration versus true lipid dryness
