Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceExplore soothing and barrier-repair actives ideal for sensitive, dehydrated skin. Understand mechanisms and usage 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 balanceOutline core design principles for sensitive, dehydrated skin: minimalism, low irritation, and barrier support. Learn to restrict actives, avoid repeats, and balance humectants with emollients in a simple 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 rangesSee how humectants, occlusives, and emollients team up to hydrate sensitive, dehydrated skin. Review glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with practical usage 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 compatibilityTarget skin-friendly pH levels and create buffer systems protecting skin and formula. Handle compatibility with actives, surfactants, preservatives, and track 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 for sensitive formulas. Compare approved types, usual levels, boosters, and risks/controls for preservative-free options.
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 declarationBuild a fragrance and allergen plan for sensitive skin. Compare fragrance-free, essential oils, low-allergen mixes, apply IFRA limits, and handle allergen labelling.
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 guidanceChoose ultra-mild surfactant systems for cleansers for sensitive, dehydrated skin. Compare nonionic, amine oxide, zwitterionic types, set safe levels, and create low-foam, gentle 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: prioritising safety, evidence, and multifunctional activesCreate an ingredient selection framework prioritising safety, evidence, and multi-benefits. Interpret safety data, assess in vivo/in vitro proof, and pick multi-tasking ingredients.
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 feel for minimalist systems. Compare O/W creams, water-serums, gel-creams, pick viscosity adjusters, and fine-tune slip, playtime, afterfeel for delicate 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 drynessSee how weak barriers, TEWL, and nerve sensitivity define sensitive, dehydrated skin. Identify triggers, dehydration vs dryness differences, and implications for textures, actives, surfactants.
Stratum corneum structure and lipid organizationTEWL, corneometry, and hydration assessmentNeurosensory hyperreactivity and stingingTriggers: surfactants, pH, fragrance, alcoholsDehydration versus true lipid dryness
