Overview
This lecture covers the principles of cosmetic chemistry, types of mixtures and emulsions, skincare products, functional and performance ingredients, and regulatory considerations relevant to estheticians.
Cosmetic Mixtures & Classifications
- Most skincare products are mixtures of two or more substances.
- Solutions are mixtures where substances are evenly dispersed and mixable.
- A solvent dissolves another substance (solute).
- Immiscible mixtures involve molecules that cannot be mixed.
- Products requiring shaking before use are suspensions.
- Suspensions separate when left standing.
- Liquid foundation is classified as an emulsion.
- Soaps are fats and oils converted to fatty acids by heat and purification.
- Powders must be sifted until free of coarse particles.
- Ointments are mixtures of organic substances and medicinal agents.
Emulsions & Delivery
- Emulsions are two or more immiscible substances united with a binder.
- Examples of emulsions: mayonnaise, cold cream.
- Oil-in-water is a common cosmetic emulsion (e.g., moisturizing lotions).
- Most industry emulsions are oil-in-water type.
- The solute is the powder mix in Kool-Aid.
- A saturated solution cannot dissolve more solute at a given temperature.
- The non-polar end of an emulsifier is lipophilic (oil-loving, water-hating).
Skincare Products & Routines
- Cleansing removes dirt, oil, makeup, and pollutants from the skin.
- Use oil-free makeup remover for clients with false eyelashes.
- Toners cleanse further and balance skin pH; fresheners have the lowest alcohol content.
- Exfoliation removes dead skin; physical (granular scrub) or chemical (enzymes/AHAs).
- Lotions are moisturizers with high water content and light consistency.
Sun Protection
- Sun exposure is the main cause of skin cancer and premature aging.
- SPF is based on UVB rays.
- Physical sunscreens reflect UV rays (e.g., zinc oxide, titanium dioxide).
- Broad spectrum sunscreen protects against UVA and UVB.
- Chemical sunscreens include oxybenzone, avobenzone, and octinoxate.
Masks, Treatments & Special Care
- Clay masks absorb excess oil and refine pores.
- Peel-off masks lock in moisture and tighten skin.
- Paraffin masks are used for hand and face, but do not absorb oil.
- Gel masks soothe sensitive skin.
- Organically grown ingredients are free from pesticides and GMOs.
Ingredients & Labeling
- Delivery systems (liposomes, microsponges, hydrogels) control ingredient release.
- Water is typically the first ingredient on product labels due to its weight.
- Humectants hold water in the skin.
- Emulsifiers are compatible with oil and water.
- Surfactants (cleansing agents) remove oil and dirt.
- Emollients prevent moisture loss.
- Preservatives protect against bacteria and extend product life.
- Colorants enhance product appearance.
- pH adjusters alter product acidity/alkalinity.
- Fragrances mask raw ingredient odors.
- Hypoallergenic means less likely to cause allergies.
- Performance ingredients produce the intended effect.
Product Safety & Regulation
- Non-comedogenic ingredients do not clog pores.
- Over-the-counter (OTC) products are sold without a prescription.
- Antibacterial ingredients destroy acne-causing bacteria.
- Ingredients are listed on labels by descending concentration.
- FDA regulates cosmetics in the U.S.
Key Terms & Definitions
- Emulsion — a mixture of two immiscible substances held together by a binder.
- Surfactant — a cleansing agent that removes oil and dirt.
- Humectant — ingredient that retains moisture in the skin.
- Broad Spectrum — sunscreen that blocks both UVA and UVB rays.
- Hypoallergenic — less likely to cause allergic reactions.
- Non-comedogenic — does not clog pores.
Action Items / Next Steps
- Review product labels and identify functional and performance ingredients.
- Read assigned chapter on cosmetic chemistry and regulations.
- Prepare to discuss skincare routines and ingredient functions in next class.