Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceGet into soothing and barrier-fixing actives good for sensitive, dry skin. Learn how they work and amounts for panthenol, niacinamide, ceramides, cholesterol, fatty acids, and oat parts 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 balanceSet out main design ideas for sensitive, dry skin: keeping it simple, low irritation, and barrier support. Learn to cut down actives, skip 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 rangesSee how humectants, occlusives, and emollients team up to moisten sensitive, dry skin. Check glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with useful amount 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 make buffer systems that guard skin and formula. Deal with matching actives, surfactants, and preservatives, and watch pH changes over time on the shelf.
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 preservative setups good for sensitive formulas. Compare allowed groups, usual amounts, and helpers, and know the dangers and controls for 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 declarationMake a fragrance and allergen plan good for sensitive skin. Compare no-fragrance, essential oils, and low-allergen mixes, use IFRA limits, and handle EU-style allergen labelling and what consumers expect.
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 to pick very mild surfactant setups for cleansers aimed at sensitive, dry skin. Compare nonionic, amine oxide, and zwitterionic choices, set safe amounts, and make 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: prioritizing safety, evidence, and multifunctional activesBuild a framework for picking ingredients that puts safety, proof, and multi-use first. Learn to read safety info, weigh live and lab support, and choose ingredients that give many benefits together.
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 lineGet good at rheology and feel design for simple systems. Compare O/W creams, water-serums, and gel-creams, pick viscosity helpers, and adjust slip, playtime, and afterfeel for delicate, easily overwhelmed 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 mark sensitive, dry skin. Learn main triggers, how dehydration differs from real dryness, and what that means for picking textures, actives, and surfactant setups.
Stratum corneum structure and lipid organizationTEWL, corneometry, and hydration assessmentNeurosensory hyperreactivity and stingingTriggers: surfactants, pH, fragrance, alcoholsDehydration versus true lipid dryness
