Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceDive into soothing and barrier-repair actives suited to sensitive, dehydrated skin. Learn mechanisms and use levels for panthenol, niacinamide, ceramides, cholesterol, fatty acids, and oat derivatives within minimalist 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 core design principles for sensitive, dehydrated skin: minimalism, low-irritancy, and barrier support. Learn to limit actives, avoid redundancy, and balance humectants with emollients across a streamlined 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 work together to hydrate sensitive, dehydrated skin. Review glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with practical use-level 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 target skin-friendly pH ranges and design buffer systems that protect both skin and formula. Address compatibility with actives, surfactants, and preservatives, and monitor pH drift over shelf life.
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 appropriate for sensitive formulations. Compare approved families, typical use levels, and boosters, and understand the risks and controls needed when pursuing preservative-free claims.
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 strategy suitable for sensitive skin. Compare fragrance-free, essential oils, and low-allergen blends, apply IFRA limits, and manage EU-style allergen labelling and consumer expectations.
Fragrance-free versus low-scent approachesEssential oils and sensitization riskUsing IFRA categories and maximum levelsLabelling listed fragrance allergensMasking base odors without overloadingLesson 7Gentle surfactants and mild cleansing systems: non-ionic/amine oxide/zwitterionic options and concentration guidanceLearn how to choose ultra-mild surfactant systems for cleansers targeting sensitive, dehydrated skin. Compare nonionic, amine oxide, and zwitterionic options, set safe use 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 selection framework that prioritizes safety, evidence, and multifunctionality. Learn to interpret safety data, weigh in vivo and in vitro support, and favor ingredients that deliver 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 minimalist systems. Compare O/W creams, water-serums, and gel-creams, select viscosity modifiers, and tune 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 impaired barriers, TEWL, and nerve hyperreactivity define sensitive, dehydrated skin. Learn key triggers, how dehydration differs from dryness, and what this means for selecting 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
