Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceExplore soothing and barrier-repair ingredients ideal for sensitive, dehydrated skin. Understand their actions 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 main design principles for sensitive, dehydrated skin: simplicity, low irritation, and barrier support. Learn to restrict actives, cut redundancy, and balance humectants with emollients in 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 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 compatibilityLearn to aim for skin-friendly pH levels and create buffer systems that safeguard skin and formula. Tackle compatibility with actives, surfactants, and 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 managementCheck out preservative systems fit for sensitive formulas. Compare approved types, usual levels, and enhancers, and grasp risks and 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. Weigh fragrance-free, essential oils, and low-allergen mixes, follow IFRA rules, and handle EU-style allergen labelling and consumer hopes.
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 guidanceFind out how to select very mild surfactant systems for cleansers aimed at sensitive, dehydrated skin. Compare nonionic, amine oxide, and zwitterionic choices, set safe levels, and craft low-foam, low-irritation 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 that puts safety, proof, and multi-use first. Learn to read safety info, assess in vivo and in vitro data, and pick ingredients offering multiple benefits.
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 flow and feel design for simple systems. Compare O/W creams, water-serums, and gel-creams, choose thickeners, and adjust slip, application time, and afterfeel for delicate, overload-prone 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 drynessLook at how weak barriers, TEWL, and overactive nerves characterise sensitive, dehydrated skin. Identify main triggers, how dehydration differs from dryness, and implications for textures, actives, and surfactants.
Stratum corneum structure and lipid organizationTEWL, corneometry, and hydration assessmentNeurosensory hyperreactivity and stingingTriggers: surfactants, pH, fragrance, alcoholsDehydration versus true lipid dryness
