A continuation of  a list and brief definition of commonly used ingredients in cosmetic formulations. Note: allergies may occur with the use of any chemical, essential oil, herb or spice. It is advisable to test a small area of the skin prior to using the product in the shower of bath. Many of these ingredients are used in major formulations, but are becoming more available for the hobbyist and small formulator.

Neopentyl glycol dicaprylate/dicaprate: Used as a lubricant; soothing and softening to the skin. It is a compound of neopentyl glycol, which is derived synthetically, and dicaprylate/dicaprates, which are derived from coconut. Caprylates are in the glyceride family and are found in human sebum.

Neroli: Essential oil distilled from the flowers of the bitter orange tree. Used in aromatherapy to ease nervous tension and induce calm.

Nonoxynol-10: A synthetic ingredient used as a dispersing agent to solubilize essential oils. Not to be confused with the spermicide nonoxynol-9.

Oatmeal: Exfollient, healing.

Octoxynol-l: Used as an emulsifier and dispersing agent.

Octyl methoxycinnamate: Sunscreen, UVB blocker. Derived from cinnamon or cassia oil. Less irritating than PABA.

Octyl palmitate: 2-ethylhexyl alcohol reacted with palmitic acid. See Palmitic acid.

Octyl stearate: The ester of 2-ethylhexyl alcohol, a fatty alcohol. Octyl stearate may be derived from tallow or vegetable oils.

Oleic acid: A common constituent of many animal and vegetable fats and, therefore, of most normal diets.  Used in cosmetics as an emollient in creams and lotions. Can be mildly irritating.

Oleyl alcohol: Found in fish oils; has softening and lubricating qualities.

Olive oil: Natural oil used as an emollient in soaps, cleansers, and shampoos. Prevents loss of natural moisture, softens skin and attracts external moisture to the skin.  Treats rheumatism, muscle pains and inflamed skin.  Thick; dilute 10-50% with carrier oils.  Blends well with lavender and rosemary.  Long shelf life.

Oxybenzone: See Benzophenone. Ozakerite: See Ceresin wax.

PABA: See Para-aminobenzoic acid.

Padimate-O: Brand name for PABA.

Palmarosa oil: The essential oil of palmarosa grass (Cymbopogan martini). Exceptional in bringing hydration to the skin, it is also an effective cellular renewal ingredient.

Palmitate: Salt of palmitic acid. Used as an oil in many cosmetics. See Palmitic acid.

Palmitic acid: A natural fatty acid found in palm, cottonseed, peanut, ricebran, sorghum, and other natural vegetable oils. Used as an emulsifier, surfactant and texturizer.

Palm kernel oil: Oil from an African palm nut. When saponified, forms a high-sudsing cleaning agent used in soaps.

Panthenol: Part of the water-soluble vitamin B complex.

Pantothenic acid: The result of a reaction in skin enzymes to panthenol.  Acts as an healing agent.

Papain: An active proteolytic enzyme found in papaya; the most potent form comes from unripened green papaya. Used in exfoliants to dissolve dead skin cells.

Para-aminobenzoic acid (PABA): A sunscreening agent. Possibly phototoxic and photoallergenic; a common sensitizer.

Parabens: Broad-spectrum preservatives derived from plant or petroleum sources. Effective against bacteria, fungus, yeast, and mold. Parabens are some of the safest preservatives, effective over a wide pH scale.

Paraffin: Derived from petroleum. Used as a thickener for cosmetic creams.

Patchouli: Promotes cell regeneration, healing, anti-fungal, antiseptic,  anti-bacterial, insect repellent; Aromatherapy: anti-depressant.

PEG: An abbreviation for polyethylene glycol, a synthetic polymer used as a humectant, emulsifier, emollient, binder, solvent, and stabilizer; protects against oxidation and moisture loss. It is derived from natural gas. Higher numbers indicate more PEG chains are present in the molecule.

PEG-5 ceteth-10 phosphate: A compound of polyethylene glycol, ceteth (from coconut fruit), and ethylene oxide, with phosphoric acid (which is produced synthetically).  Used as an emulsifier.

PEG-7 glyceryl cocoate: A combination of polyethylene glycol and glyceryl cocoate (derived from coconut oil) to form a type of sucrose (sugar) extract. It is a mild cleansing agent and emollient that breaks up fat on the skin’s surface without stripping the skin’s natural oils or causing dryness. Rinses completely from the skin with water. It may be used in place of sodium lauryl or laureth sulfate, which are both drying and stripping for the skin.

PEG-8: A polymer of ethylene oxide. Acts as an emollient, plasticizer, and softener for cosmetics creams and shampoos.

PEG-40 castor oil: A compound made from polyethylene glycol (PEG) and castor oil, an extract of the castor bean. This ingredient is used as a solvent to help disperse other ingredients in a solution.

PEG-100 stearate: Polyethylene glycol combined with stearic acid to form a water-soluble ester used as an emulsifier and emollient; has a softening effect on the skin.

Peppermint oil: An essential oil containing menthol that has a cooling effect on the skin. May be irritating to mucous membrane.   Blends well with bergamot, eucalyptus, geranium, juniper and lavender.  Avoid if pregnant.  May irritate skin – dilute to 1%.

Petrolatum: Also known as petroleum jelly, paraffin jelly, Vaseline. Forms an occlusive barrier on the skin, which limits the skin’s ability to function. Common comedogenic ingredient.

Phenyl mercuric acetate: Used as a preservative in shampoos and eye cosmetics. It is highly toxic if inhaled or swallowed and can cause skin irritation.

Phosphoric acid: Functions as a metal ion sequester and an acidifier.

Polyaminopropyl biguanide: A synthetically derived preservative. It was originally developed by Bausch and Lomb for use in eye products worn by contact lens wearers. It is one of the most gentle, yet effective, antimicrobial preservatives available.

Polysorbate 20: Derived from sorbitol. It is a water-soluble yellowish liquid used as a dispersing agent and stabilizer, and it has a soothing effect on the skin. Some allergic reactions reported.

Potassium hydroxide (caustic potash): Used in the manufacture of liquid soaps and bleaches.

Potassium sodium copper chlorophyllin: A natural colorant derived from chlorophyll.

Propylene glycol: Appears in many cosmetics as a solvent, conditioning agent, and humectant. Can be irritating if more than 5 percent is used in a formulation.

Propylene glycol stearate: Functions as an emollient, thickener, and emulsion stabilizer in creams and lotions.

Propyl gallate: Acts as an antioxidant (preservative).

Propylparaben: A preservative derived from PABA that is widely used in cosmetics. Its fungicidal and antibacterial abilities help prevent yeast and mold. Nontoxic and nonirritating at .05 of 1 percent. (It may be irritating to the skin if more than 5 percent is present in a formulation.)

PVM/MA copolymer: Has thickening, dispersing, and stabilizing properties;  highly irritating to eyes, skin, and mucous membrane.

PVP: Forms a hard, transparent, lustrous film. Used primarily in hair sprays.

Quatemium-15: A synthetic preservative and bactericide derived from ammonium chloride. May be irritating to the skin if more than 5 percent is used in a formulation.

Quatemium-18: Used as a conditioning agent in hair conditioners. It is an eye irritant and can cause contact dermatitis.

Quatemium-19: A substantive (clinging) hair conditioner.

Resorcinol: Irritating to the skin and mucous membrane. Sometimes used as an antidandruff agent because of its antiseptic properties.

Retinoic acid (Retin-A): Vitamin A acid. A chemical skin exfoliant. May irritate skin and cause sun sensitivity.

Retinyl palmitate: Vitamin A. A primary antioxidant vitamin, free-radical scavenger and cellular renewal ingredient (healer).

Rice bran oil: An ingredient rich in vitamin E derived from the bran of rice. It is very similar to wheat germ oil but not as “heavy,” because it has a smaller molecule that is able to more easily penetrate the skin.

Rosemary oil: An essential oil invigorating to the circulation as well as to the psyche.

Rosewood oil: Distilled from the bark of the Aniba rosenodora tree that grows in the Amazon rain forest.  It is high in linalool, making it balancing and healing. It also has antibacterial and analgesic abilities. Most rosewood is now protected, and the oils can only be purchased from licensed agents. It, unfortunately, is becoming like sandalwood, in that indigenous people are being murdered so poachers can get access to this rare plant.  Ethically, I believe you should avoid this oil unless your supplier can prove that it is sourced from the licensed broker.