Types of Cosmetic Ingredients and Their Functions

Solvents

• Isoparaffins (liquefied gas): Isopentane, Butane, Isobutane, Propane
• Solvents used to dissolve components, provide a vehicle, or contribute to texture in lotions, body creams, nail polish, and hair spray
• Also used to stabilize the formulation, regulate evaporation rate, provide cooling effect, and aid in product application

Surfactants

• Anionic: foam building and cleaning, sometimes irritating
• Cationic: conditioning for skin and hair
• Amphoteric: cleansing, softening, foam building
• Examples: Stearic Acid, Sodium lauryl sulfate, Sulfonates, Sulfosuccinates
• Functions: cleaning/detergency, foam formation, thickening, emulsification

Sweeteners

• Artificial sweeteners: Peppermint, Strawberry, Artificial (chocolate, bubble gum)
• Add aesthetic impression due to nice smell
• Lower content in personal care products than in perfumes

Moisturizers

• Humectants: Glycerin, Sorbitol, Urea, Propylene glycol
• Emollients: Seed and nut oils, Lanolin, Synthetic esters of fatty alcohols and fatty acids
• Occlusives: Petrolatum, Mineral Oil, Paraffin, Carnauba or waxes, Stearic Acid, Cetyl Alcohol
• Functions: add moisture or help retain moisture, replenish oils and lipids, enhance skin barrier/skin rejuvenators

pH Buffers

• Citric acid, Lactic acid, Sodium hydroxide, Triethanolamine
• Match the formulation’s pH with that of the application surface

Plasticizers

• Camphor, Castor oil, Glyceryl tribenzoate in nail polishes, Mineral dimethicone and castor oil in styling products
• Added to films to soften and impart flexibility

Preservatives

• Parabens, Glutaraldehyde, Benzalkonium chloride, Benzethonium chloride, Benzyl alcohol
• Used to protect against molds, yeasts, and bacteria

Propellants

• Added to aerosol preparations to maintain pressure and help expel contents
• Examples: Cetrimonium chloride, Benzalkonium chloride, Amphoteric Coco betaine, Lauryl betaine, Non-ionic Glyceryl monostearate, Sorbitan esters, Polysorbates, Fatty alcohols, Polyxamers, Alkanolamides, Alkylglucosides

Thickening Agents

• Increase viscosity to improve stability, modify appearance and aesthetics, improve applicability, or act as suspending agents
• Water-based: Gums like xanthan guar, Cellulose derivatives, Hydrophilic clays (bentonite), PEGs, Carbomers, Sodium Chloride
• Non-water-based: Carnauba wax, Cetyl alcohol, Fumed silica, Polymers, Polyethylenes

Alpha Hydroxy Acids (AHA)

• Improves skin firmness and elasticity
• Found in nature, involved in metabolic pathways (Kreb’s cycle, glycolysis, and serine biosynthesis)
• Promotes collagen maturation, formation of glycosaminoglycan, and stimulates epidermal turnover
• Increases resistance of skin from chemical irritation

Silicones

• Dimethicone (PDMS): an organo-silicone polymer consisting of an inorganic siloxane (Si-O) backbone with pendant organic group
• Used in emulsions, adds viscosity, and provides substantivity or durability
• Examples: Cyclomethicone (Cyclosiloxanes) - volatile solvents, Dimethicones (PDMS) - used in emulsions, Silicone blends of Dimethicone Gums or Resins - increased substantivity or durability

UV Filters

• Physical absorption and blocking: PABA derivatives, Octyl dimethyl PABA
• Chemical absorption: Cinnamates, methoxycinnamate, Octyl UV-B
• Broad spectrum: provides both UV-A and UV-B protection
• Water-resistant: maintains the SPF level after 40 minutes of water immersion
• Examples: Benzophenones, Avobenzone, Octocrylene

Vitamins

• Vitamin E: non-enzymatic antioxidant, stabilizes biological membranes with large amounts of polyunsaturated fatty acids
• Vitamin A: stimulates cell proliferation and cell renewal, increases collagen content of the dermis
• Vitamin C: water-soluble, non-enzymatic antioxidant, protects from UV-B damage if combined with Vitamin E
• Panthenol: acts as a humectant, ideal in baby care products or for sensitive skin
• Biotin: good for nails and hair due to effect on keratinization