Lesson 1Active dosing plan: selecting an effective yet tolerable percentage range and rationaleThis part teaches setting active amounts that work but don't irritate. You'll read studies, real tests, and rules, set starting ranges, and plan step-by-step tweaks while watching total exposure in daily use.
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 covers picking solvents and helpers like water, glycols, propanediol, and oils. You'll see how their nature, drying speed, and mixing affect dissolving, staying good, skin feel, and delivery for water-loving and 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 looks at softening agents and feel changers like esters, caprylic/capric triglycerides, and squalane. You'll learn to adjust spread, richness, and leftover feel while helping skin barrier and active tolerance.
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 stabilisers for sensitive actives. You'll study vitamin E, ferulic acid, metal grabbers like EDTA, and build matching systems for your formula 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 explores water holders and moisturisers like glycerin, propanediol, sodium hyaluronate, and butylene glycol. You'll learn to mix them for good hydration, no stickiness, skin entry, 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 guides picking serum type by active needs. You'll compare water-based, emulsion, and dry serums with a choice guide weighing dissolving, staying good, feel goals, pack, and what customers expect.
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 explains how thickeners and flow changers shape feel, spread, and holding bits. You'll compare carbomers, xanthan gum, polyacrylates, and tune clear vs cloudy and sensory 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 shows picking pH changers and stabilisers to guard actives and skin. You'll choose acids, bases, buffer mixes, measure and adjust pH, and stop changes over shelf 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 explains building germ protection for gentle formulas. You'll compare preservatives, boost with metal grabbers and water holders, check fit with pH, soaps, natural claims, and safety rules.
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 skin entry boosters and delivery systems, covering solvents, short alcohols, glycols, esters, and new wrap methods to better dissolve, stabilise, target skin, and cut irritation.
Role of solvent polarity in skin permeationShort-chain alcohols: efficacy vs irritationUse of glycols and propylene glycolEster-based penetration enhancersLiposomes and solid lipid nanoparticles
