Basic terminology of cosmetic science

Active ingredients are multifunctional components usually added at the end of preparation. Appropriate combinations of active ingredients help to achieve the desirable effect of a formulation.
Examples: alpha-bisabolol, hyaluronic acid, vitamins.

Antioxidants are active ingredients that inhibit oxidation process. They prevent degradation of other cosmetic ingredients and also protect the skin.
Examples: vitamin C, vitamin E, coenzyme Q10.

Carrier (base) butters are plant-derived water-insoluble products in a solid form. Chemical nature – triglycerides.
Examples: mango butter, coconut butter.

Carrier (base) liquid oils are plant-derived water-insoluble products in a liquid form. Chemical nature – triglycerides.
Examples: olive oil, grape seed oil.

Emulsifiers are “magic” cosmetic ingredients that allow us to “mix” the oil phase and the water phase of an emulsion and prevent their separation from each other.
Examples: BMTS, polawax.

emulsifier polawax
Emulsifier polawax

Essential oils are products containing water-insoluble odorant compounds of plants.
Examples: bergamot essential oil, jasmine essential oil.

HLB value (hydrophilic-lipophilic balance) is an indicator of hydrophility (water receptivity) or lipophility (oil receptivity) of a surfactant (at the scale of 0-20) (3). If a surfactant has a HLB value above 10 it is hydrophilic (water-soluble); if a HLB value is less than 10 it is lipophilic (or water-insoluble). The HLB value is useful for predicting properties of surfactants. For example, emulsifiers with HLB value 12-16 will give O/W emulsion, emulsifiers with HLB 3-6 will give W/O emulsion.

Hydrolates (floral waters; hydrosols) are aqueous products obtained by steam distillation of plant parts. It contains water-soluble plant ingredients, organic acids and some compounds of essential oils.
Examples: lavender floral water, rose floral water.

Oil phase of emulsion is formed by all base oils and butters, waxes and emulsifier(s) (Figure).

Oil in water emulsion (O/W) is the most common type of emulsion where droplets of oil are dispersed in water

oil in water emulsion, O/W emulsion
Oil in water emulsion (O/W)
Drops of oil are evenly dispersed in water; an emulsifier prevents them from aggregation

Patch test is a routine method for identification of a substance (or substances) that cause allergic contact dermatitis. Different allergens are applied on the upper part of the back and fixed with adhesive tape. In 48-72 hours dermatologist removes the patches and examines the skin 4.

Percentage of use is the relative amount of certain cosmetic ingredients in a finished product; it indicates how much of these ingredients have to be added.
Example: percentage of use for one component is 3-5%; it means that you can add 3-5 g of this ingredient per 100 g of the final product.

pH is an indicator of acidity or basicity (at the scale of 0-14) (1). Therefore, depending on pH value substances are divided into acidic (pH<7.0), basic (pH>7.0) and neutral (pH=7.0). Acidic solutions: lemon juice, vinegar. Neutral solutions: distilled water. Basic solutions: soap, lye. pH is an important parameter in cosmetics manufacturing. Depending on the skin type, pH value of our skin can vary from 4.0 (dry skin) to 7.0 (oily skin) (2).

pH, homemade cosmetics, cosmetics making
pH indicator paper

Preservatives are ingredients or mix of ingredients that prevent growth of bacteria and fungi in a cosmetic product.
Examples: potassium sorbate, methylparaben. If you want to know more about preservatives you can read here.

Surfactants are compounds that reduce surface tension of water. They can act as detergents, emulsifiers, or foaming agents.
Example: coco-glucoside.

Thickeners are substances that increase viscosity of a liquid or an emulsion.
Example: xanthan gum.

Water phase of emulsion is formed by distilled water, hydrolate (floral water) and ingredients that are soluble in water and can sustain heating.

water phase of emulsion, oil phase of emulsion, cosmetics making, homemade cosmetics
Oil phase of emulsion               Water phase of emulsion  

Waxes are solid water-insoluble products of plant or animal origin. Chemical nature – lipid.
Examples: beeswax, soya wax.

Water in oil emulsion (W/O) is a type of emulsion where droplets of water are dispersed in oil.

water in oil emulsion, W/O emulsion, cosmetics making
Water in oil emulsion (W/O)

 

Any other cosmetic terminology that you would like to know? Mention it in the "Comments"  below!

 

References:

  1. Covington, A. K.; Bates, R. G.; Durst, R. A. (1985). "Definitions of pH scales, standard reference values, measurement of pH, and related terminology". Pure Appl. Chem. 57 (3): 531–542.
  2. Lambers H, Piessens S, Bloem A, Pronk H, Finkel P. Natural skin surface pH is on average below 5, which is beneficial for its resident flora. Int J Cosmet Sci. 2006 Oct;28(5):359-70. doi: 10.1111/j.1467-2494.2006.00344.x.
  3. Griffin, William C. (1949), Classification of Surface-Active Agents by 'HLB', Journal of the Society of Cosmetic Chemists 1 (5): 311-26.
  4. National Library of Medicine - Medical Subject Headings. Patch testing.

Comments

1
Drosofila's picture

great article! that's what I was looking for!