Lesson 1Soothing and barrier-repair actives: panthenol, niacinamide, ceramides, cholesterol, fatty acids, oat extract (Avena), and use-level guidanceDive into calming and barrier-fixing actives fit for sensitive, dry skin. Learn how they work and use amounts 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 balanceSet core design ideas for sensitive, dry skin: keeping it simple, low irritation, and barrier support. Learn to cut down actives, skip repeats, and balance moisture drawers with softeners in a smooth 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 moisture keepers, sealers, and softeners team up to hydrate sensitive, dry skin. Review glycerin, hyaluronic acid, propanediol, squalane, esters, and fatty alcohols with handy 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 levels and build buffer systems that guard both skin and formula. Tackle matches with actives, cleansers, 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 keeping systems right for sensitive formulas. Compare allowed groups, usual amounts, and helpers, and get the risks and controls for going without preservatives in 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 declarationBuild a scent and allergen plan fit for sensitive skin. Compare no-scent, essential oils, and low-allergen mixes, use IFRA limits, and handle EU-style allergen labels and buyer 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 guidanceLearn to pick super-mild cleanser systems for sensitive, dry skin. Compare nonionic, amine oxide, and zwitterionic choices, set safe levels, and make low-bubble, low-irritant 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 picking framework for ingredients that puts safety, proof, and multi-use first. Learn to read safety info, weigh live and lab support, and pick items 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 lineMaster flow and feel design for simple systems. Compare oil-in-water creams, water-serums, and gel-creams, choose thickness adjusters, and tune smoothness, play, and 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 drynessExplore how weak barriers, water loss, and overactive nerves mark sensitive, dry skin. Learn main triggers, how lack of water differs from dryness, and what it means for textures, actives, and cleansers.
Stratum corneum structure and lipid organizationTEWL, corneometry, and hydration assessmentNeurosensory hyperreactivity and stingingTriggers: surfactants, pH, fragrance, alcoholsDehydration versus true lipid dryness
