O

occlusive agents

Occlusive agents are materials (like plastic wrap and Band-Aids) that hold strongly to the surface of the skin, increasing absorption and blocking access to the air. Occlusive agents have been used for thousands of years to speed healing of wounds and as beauty treatments.

ocotea cymbarum oil

This essential oil, obtained by steam distillation from the bark of a Brazilian tree (Ocotea cymbarum), has a high safrole content, and is used as a substitute for sassafras oil.

oils

These viscous substances, which are generally insoluble in water, are obtained from animal, plant, mineral and synthetic sources.

ointment

A semisolid preparation for the skin, usually with a fatty or greasy base.

oleic acid

Thisfattv acid, a common constituent of many animals and vegetables, is also a common cosmetic ingredient. It can be isolated from vegetable oils or produced from inedible tallow. When hydrogenated, oleic acid yields stearic acid.

stearic acid.

oleoresins

These plant products consist of essential oils and resins in solution (examples are gums, turpentines and balsams). Oleoresins can occur naturally (Oregon balsam is an example) or they can be extracted by means of solvents from plants like paprika and ginger.

oleth-2 through oleth-50

These polyethylene glx’col ethers of oleic alcohol are used as surfactants. They’re synthetic chemicals and can cause allergic reactions.

oleyl alcohol

This fatty alcohol,

This fatty alcohol, an oily, unsaturated liquid found in fish oils or manufactured from esters of oleic acid, is used to make surface-active agents.

olfactory

Relating to the sense of smell.

1-na phthol and 2-na phthol

These coal tar derivatives are used as antiseptics, parasiticides and dye intermediates. They can irritate the skin and are harmful to the environment. They’re absorbed through the skin, and oral doses larger than one teaspoon can be fatal. See colors.

opacifying agent or opacifier

A substance that changes the appearance of cosmetics from clear to cloudy. An example is titanium dioxide.

0-phenyiphenol

This phenolic compound is very toxic. Its trade names are Doxicide I and Preventol 0.

oral

By mouth.

organic

Carbon is an essential part of every organic compound, and is necessary for all living things. In today’s chemistry, the term organic means that the substance described contains a carbon atom. But when the term was originally defined by the Swedish chemist Berzelius, it described any substance that is, or once was, living. In this book, I follow Berzelius’ definition.

origanum oil

This oil, related to marjoram, comes from the Thymus capitatus plant. It’s used as a fragrance in cosmetics and as a flavoring in foods. It’s a natural oil, but some people may be allergic to it.

orris

An essential oil derived from European plants of the genus Iris, especially Iris pallida, orris is used as a flaxoring and fragrance. Orris root is also powdered and used in sachets, tooth powders and as a powder base.

ouricury wax

See waxes.

Oxadine A

This toxic amine substitute is used in protein shampoos and hand creams at concentrations of .05%—O.2%.

oxidation

This common chemical reaction is caused by the combination of oxygen and another substance. Fire and rust are both examples of oxidation, as is butter (or anyfat or oil) turning rancid.

Oxidation is an important cause of cosmetics deterioration (as is the activity of microorganisms), though topical application of a product whose fats are rancid isn’t as harmful as consuming one (rancid fats in the diet can destroy certain vitamins and other essential elements, and may cause cancer). Antioxidants inhibit oxidation, and thus protect the oil phase of cosmetics from becoming rancid.

oxyquinoline

This aromatic alcohol, usually derived from coal tar, is used as an antimicrobial. It can cause allergic reactions.

ozokerite wax

See waxes.