Lesson 1Active dosing plan: selecting an effective yet tolerable percentage range and rationaleThis part teaches setting active amounts that work but don't bother skin. You'll read studies, live tests, and rules, set start ranges, and plan step tweaks while watching total use in daily care.
Reading literature and supplier dataMinimum effective vs plateau dosesSafety margins and irritation thresholdsLayering with other products in a routinePilot batches and consumer feedback loopsLesson 2Solvents and co-solvents selection: water, glycols, propanediol, oils — impact on solubility and stabilityThis part picks carriers and helpers like water, glycols, propanediol, oils. You'll see how pull, dry-off, and mix power affect dissolving, holding, skin touch, and delivery for water-loving or oil-loving actives.
Water quality and microbiological controlUsing glycols to improve solubilityPropanediol as humectant co-solventOil phase choice for lipophilic activesSolvent impact on stability and feelLesson 3Emollients and skin-feel modifiers: lightweight esters, caprylic/capric triglycerides, squalane — balancing aesthetics and skin toleranceThis part checks smoothers and feel changers like esters, caprylic/capric triglycerides, squalane. You'll tune spread, fullness, after-touch while helping skin shield and active kindness.
Lightweight esters for fast absorptionCaprylic/capric triglycerides as base emollientSqualane for barrier support and slipSilicone vs non-silicone feel strategiesComedogenicity and skin type matchingLesson 4Antioxidants and stabilizers to protect actives: vitamin E (tocopherol), ferulic acid, chelators (EDTA), and rationaleThis part covers fighters against air damage and keepers for touchy actives. You'll study vitamin E, ferulic acid, grabbers like EDTA, and build team systems for mix type and pack.
Oxidation pathways in cosmetic formulasVitamin E (tocopherol) in oil phasesFerulic acid to support vitamin C systemsChelators such as EDTA and alternativesPackaging and oxygen exposure controlLesson 5Humectants and moisturizers: role of glycerin, propanediol, sodium hyaluronate, butylene glycol and selection guidanceThis part looks at water holders and moist makers like glycerin, propanediol, sodium hyaluronate, butylene glycol. You'll mix them to balance wet feel, stick, sink-in, and active fit.
Glycerin levels and tack controlPropanediol as mild humectant solventSodium hyaluronate grades and weightsButylene glycol for slip and solvencyHumectant blends for different climatesLesson 6Designing the serum type: water-based serum, emulsion serum, anhydrous serum — selection matrix based on chosen activeThis part picks serum type from active needs. You'll match water-based, cream-like, dry serums with a choice chart weighing dissolve, hold, feel aims, pack, and buyer hopes.
Water-based serums for hydrophilic activesEmulsion serums for mixed solubility needsAnhydrous serums for unstable activesDecision matrix by active and skin typePackaging choices for each serum typeLesson 7Thickeners and texture agents: carbomers, xanthan gum, polyacrylate rheology modifiers and considerations for clarity vs opacityThis part shows how thickeners and flow changers shape feel, spread, hold bits. You'll match carbomers, xanthan gum, polyacrylates, tuning clear, cloudy, touch for formats.
Carbomer types and neutralization needsXanthan gum for natural, elastic texturesPolyacrylate rheology modifiers in gelsBalancing clarity, opacity, and viscosityPreventing syneresis and phase separationLesson 8pH adjusters and buffers: selection and how to control formula pH to protect actives and skin compatibilityThis part explains picking pH changers and holders to guard actives and skin. You'll choose acids, bases, pairs, check and tweak pH, stop shifts over time and use.
Target pH ranges for key activesCommon acids and bases for adjustmentBuffer systems and ionic strengthpH drift causes and preventionpH measurement and calibration basicsLesson 9Preservative systems and strategies for low-irritancy formulas: preservative selection, boosting with chelators, and preservative compatibilityThis part builds keeper systems for kind formulas. You'll match common keepers, boost with grabbers and water holders, check fit with pH, soaps, natural talk while hitting safety.
Regulatory limits and global preservative listsOrganic acids and pH-dependent systemsPreservative boosting with chelatorsSynergy with humectants and glycolsChallenge testing and risk assessmentLesson 10Penetration enhancers and delivery systems: role of solvents, short-chain alcohols, propylene glycol, esters, and encapsulation approaches (liposomes, solid lipid nanoparticles)This part explains sink-in helpers and delivery ways, covering carriers, short alcohols, glycols, esters, wrap systems to better active dissolve, hold, skin aim with less bother.
Role of solvent polarity in skin permeationShort-chain alcohols: efficacy vs irritationUse of glycols and propylene glycolEster-based penetration enhancersLiposomes and solid lipid nanoparticles
