Somerset

2. Avoid Buying Cosmetic Ingredients With Poor Labeling
Never use cosmetic ingredients that are sold with poor or lacking labeling! Typically, vitamins and other active ingredients are sold without any information about their activity (e.g. units per weight) or concentration. Often such ingredients are not pure, are highly diluted and not of cosmetic-grade quality. In addition, ingredients are sometimes sold with only a trade name but no generic name of the substance (e.g. surfactants, emulsifiers). You should never use ingredients without knowing the composition and concentration.

3. Store Cosmetic Ingredients Properly
Most ingredients have a long shelf-life (months and years) when stored correctly. Whatever type of ingredient, always use a tightly closed container, and avoid moisture and extreme temperatures as these conditions can accelerate spoiling. Certain ingredients (e.g. vitamin C and E) should be stored at light-protected places, while others should be placed in the refrigerator (e.g. sheabutter, cocoa butter and vitamin A).

4. Use Heat-Resistant Containers
Many recipes require the ingredients to be heated up to 150oF (67oC) or more. Therefore, heat-resistant containers like glas or metal jars are recommended to prevent breaking or even melting of the container. If you like to use the microwave to heat things up, you should, of course, use microwave-proof containers.

5. Avoid Overheating Oils & Other Cosmetic Ingredients
Be careful when heating oils since they are flammable at certain temperatures, spilling can produce severe burns, and when heated too long or at too high temperatures, many ingredients lose their activity and will no longer be effective. In general, active ingredients do not like to be heated and should therefore be added only after the mixture has cooled down.

6. Avoid Overdosing Cosmetic Ingredients
While commercial cosmetic manufacturers may add active ingredients at too low a concentration, home-based producers overcompensate and tend to use ingredients at too high a concentration. With most ingredients, this does no harm. There are, however, ingredients which can induce skin irritations when added at higher-than-recommended concentrations, including surfactants, fragrances, essential oils and preservatives.

7. Avoid Extreme Acidity & Alkalinity of Your Products
Extreme acidity and alkalinity can result in poor product performance or even skin irritation. The optimal pH range for cosmetics and personal care products is between 5 to 7. We recommend using a pH indicator (e.g. paper strips) to determine the pH value of your cosmetic product. When a product becomes too acidic (pH too low) or too alkaline (pH too high), you can easily correct the pH value by adding small amounts of soda (sodium carbonate prediluted in distilled water) or lemon juice, respectively.

8. Disinfect the Containers
Avoiding spoiling and growth of bacteria and fungi is important when creating homemade cosmetics. Microorganisms can not only damage your cosmetic product, but also induce skin infections. Therefore, always disinfect all containers you intend to use for making and storing your products. Isopropyl alcohol (rubbing alcohol), 70% alcohol (ethyl alcohol) or any other commercial disinfectant are all acceptable for this purpose.

9. Use Preservatives
Another measure to prevent bacterial contamination is the use of preservatives. They are natural or synthetic substances that inhibit the growth of microorganisms including bacteria or fungi, or both (see also our special article about Preservatives). Natural preservatives are less effective than synthetic ones and are usually active only against gram-positive bacteria (except grapefruit seed extract). Synthetic preservatives that are most often used for cosmetic purposes include methylparaben, propylparaben, diazolidinyl urea, phenoxyethanol, DMDM hydantoin, sorbic acid, benzyl alcohol, formaldehyde and triclosan. We recommend methylparaben, propylparaben, diazolidinyl urea, potassium sorbate and phenoxyethanol because they have been used successfully for a long time already with extremely few adverse reactions. Thiomersal, quaterniumm-15 and formaldehyde have often been found to cause skin reactions.

10. Take Precautions When Using Lyes
Lyes used for soapmaking, such as potassium hydroxide and sodium hydroxide, are caustic and can cause chemical burns on contact. Always use goggles and gloves when handling raw flakes, lye solutions and unneutralized soaps. Store these substances away from children in well-sealed, breakproof and clearly labeled containers. In case of contact with skin or eyes, rinse for several minutes with water. Lemon juice or vinegar is also effective for instant neutralization of hydroxide on the skin.

11. Label All Your Products
When your cosmetic product is completed, remember to attach a label that provides information about the type of product, date of production and perhaps also the ingredients used. The date is particularly important to monitor shelf-life. If you consider selling your products, please check the FDA labeling regulations.

12. Avoid Unsafe Ingredients
By US law, FDA does not have the authority to approve cosmetic products or ingredients, except for color additives. There are only a few ingredients which are prohibited by the FDA (see below). To ensure safety of cosmetic ingredients the cosmetic industry in combination with government has therefore undertaken a program to establish lists of ingredients which are safe to use in cosmetics. The established regulations identify cosmetic ingredients as either safe, unsafe, or also undecided when further information is required to establish safety. Unfortunately, there are many websites publishing lists of "unsafe cosmetic ingredients" based on no scientific evidence, thereby discrediting many good and acutally completely safe ingredients. True and validated scientific evidence about the safety of both natural and chemical cosmetic ingredients can be found only at the following resources:

•  CIR Reports (Cosmetic Ingredient Review): USA-based organization consisting of toxicologists, dermatologists, and representatives from the Consumer Federation of America, CTFA, and FDA.
•  EEC Cosmetic Directives: European directives formulated by the European Union consisting of a series of principles, rules, and lists of safe and unsafe ingredients.
•  FDA Monographs: In the USA sunscreens, antiperspirants and skin protectants are treated as OTC (over the counter) "drugs" which are reviewed by expert scientists to define the safety.
•  IFRA (International Fragrance Association): Association of manufacturers of fragrances. Its Technical Advisory Committee issues recommendations about the safety of various fragrances
•  Journal of the American College of Toxicology: Scientific journal publishing reports and studies about the safety of cosmetic and other environmental substances.

Determination of toxic potential is the first step in the hazard assessment of an ingredient and consists of a series of toxicity studies, specific to distinct toxicological end points. The following tests are needed to develop specific toxicity evaluation and indicate the current methodologies used for the safety evaluation of cosmetic ingredients as suggested by the EEC Cosmetic Directives:
•  Acute toxicity
•  Percutaneous absorption
•  Skin irritancy
•  Eye irritancy
•  Skin sensitisation and photosensitisation
•  Subchronic toxicity
•  Mutagenicity & genotoxicity
•  Phototoxicity & photoirritation
•  Photomutagenicity  photogenotoxicity
•  Metabolism studies
•  Long-term toxicity studies

Thus before any safety evaluation and risk assessment of a finished product is made, the degree and route of consumer exposure must be ascertained. This has to be done on a case-by-case basis but the following may provide guidance. In calculating the exposure the following factors must be considered:
•  Class of cosmetics in which the ingredient may be used
•  Method of application: rubbed-on, sprayed, rinse-off etc.
•  Concentration of ingredients in product
•  Quantity of product used at each application
•  Frequency of application
•  Total area of skin contact
•  Site of contact (e.g., mucous membrane, sunburnt skin)
•  Duration of contact (e.g., rinse-off products)
•  Foreseeable misuse which may increase exposure
•  Nature of consumers (e.g., children, people with sensitive skin)
•  Quantity likely to enter the body
•  Application on skin areas exposed to sunlight

Prohibited or Highly Restricted Ingredients
FDA regulations specifically prohibit or restrict the use of the following ingredients in cosmetics: Hexachlorophene (preservative), mercury compounds (preservative), chlorofluorocarbon (propellant), zirconium-containing complexes, halogenated salicylanilides (di-, tri-, metabromsalan and tetrachloro-salicylanilide), bithionol, chloroform, vinyl chloride, and methylene chloride.

Ingredients that Should Not Be Used
In addition to the ingredients that are controlled by regulation, cosmetic and fragrance trade associations have recommended eliminating or limiting maximum levels of certain ingredients associated with health risks. For example, the CIR and IFRA Expert Panels have found the following ingredients unsafe: Chloroacetamide (preservative), ethoxyethanol and ethoxyethanol acetate (solvent), HC Blue No. 1 (hair coloring ingredient), p-hydroxy-anisole (antioxidant), 4-methoxy-m-phenylenediamine, 4-methoxy-m-phenylenediamine HCl, and 4-methoxy-m-phenylenediamine sulfate (hair dye ingredients), pyrocatechol (used in hair dyes and skin care preparations), acetylethyl-tetramethyl-tetralin (AETT), musk ambrette, 6-Methylcoumarin (6-MC)

Ingredients that Should be Limited in Their Use
There are many cosmetic ingredients which do not exert a toxic effect as such, but may have unwanted effects if used at too high concentrations. Thus, such ingredients can still be used and can have favorable effects if added to cosmetics at the concentration as indicated. Some of them are mentioned below. In addition, the CIR Expert Panel has published a list of recommended limits for the use of a number of other ingredients which are still being widely used. You can purchase this list at CIR.

•  Alcohol: frequently used as a solvent in cosmetics. If used at concentrations of 10 % or more, the skin can dry out.
•  Sodium chloride (table salt): frequently used as cheap but effective thickener in cleansing products including shampoos or shower gels. If used at too high concentrations it can cause eye and skin irritation
•  Alpha Hydroxy Acids (AHA): skin care products containing high amounts of AHA exfoliate the skin removing wrinkles and exposing the younger skin cells beneath. As outer skin cells are exfoliated, the skin's protective barrier is removed, thus exposing premature skin to environmental damage. Therefore, use of AHA could make skin aging faster and long-term.
•  Bentonite: This porous clay able to absorb water is commonly used in cosmetic foundations and facial masks. At high concentrations, it may scratch the skin surface, clog pores, and dry out the skin.
•  Formaldehyde: When combined with water, formaldehyde is used as a disinfectant, fixative, or preservative in many cosmetic products and nail care systems. Extended use at high concentrations is thought to be carcinogenic.
•  Lanolin: Although widely used as emollient and emulsifying agent in creams and lotions, lanolin can be irritating to the skin and can cause allergic rashes.
•  Mineral Oil: As a derivative of crude oil used industrially as a lubricating agent, mineral oil can not penetrate the skin, but instead forms an oily film over the skin to lock in moisture and dirt hindering normal skin respiration. Nevertheless, it is widely used in baby skin care products!
•  Sodium Laureth Sulfate / Ammonium Laureth Sulfate (SLES, ALES): The CIR Panel has recently stated that SLES and ALES produce eye and/or skin irritation in some human test subjects. The severity of the irritation appeared to increase directly with concentration. However, SLES and ALES have not evoked adverse responses in any other toxicologic testing. It was concluded that both surfactants are safe as presently used in cosmetic products.
•  Sodium Lauryl Sulfate / Ammonium Lauryl Sulfate (SLS, ALS): The CIR Panel has recently stated that and ALS are irritants in patch testing at concentrations of 2 % and greater. The irritation increased with ingredient concentration. In some cosmetic formulations, however, that irritant property was attenuated when SLS or ALS was combined with other surfactants. The longer SLS stayed in contact with the skin, the greater the likelihood of irritation. Thus, both SLS and ALS appear to be safe in formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with skin, concentrations should not exceed 1 %.