Lesson 1Active dosing plan: selecting an effective yet tolerable percentage range and rationaleSet active amounts that work without harm. Read studies, live tests, rules; start ranges; tweak step-by-step, minding daily use buildup.
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 stabilityPick carriers like water, glycols, propanediol, oils. See how their pull, dry-off, mix affect solving, holding, feel, 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 toleranceCheck smoothers like esters, caprylic/capric triglycerides, squalane. Tune spread, richness, after-touch while aiding 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 rationaleCover guards against rust and break: vitamin E, ferulic acid, EDTA chelators. 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 guidanceExplore water-holders: glycerin, propanediol, hyaluronate, butylene glycol. Mix for balance of wet, stick, sink, 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 activeChoose serum style by active needs. Compare water, emulsion, dry; use choice grid for solve, hold, feel, pack, user 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 opacityHow thickeners shape feel, spread, hold. Compare carbomers, xanthan, polyacrylates; tune clear vs 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 compatibilityPick pH tuners, buffers for active and skin safety. Choose acids, bases, pairs; measure, adjust; stop shift over time, 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 compatibilityDesign germ-fighters for gentle mixes. Compare keepers, boost with chelators, humectants; check fit with pH, cleaners, natural claims, 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)How sink-boosters, carriers work: solvents, short alcohols, glycols, esters, wraps like liposomes, lipid bits—to better solve, hold, target skin, cut sting.
Role of solvent polarity in skin permeationShort-chain alcohols: efficacy vs irritationUse of glycols and propylene glycolEster-based penetration enhancersLiposomes and solid lipid nanoparticles