Related Terms

• Chemical hair straightening, conditioner, Japanese hair straightening, hair coloring, Henna hair dye, highlighting, keratin, shampoo, perm, permanents, thermal hair straightening,

Background

• Hair color, texture and body vary significantly among humans and are determined primarily by genetics. Temperature, humidity, and exposure to the sun also have an affect on the texture and body of hair. Hair styling is very popular among both men and women across various cultures.

• Hair is composed of strong structural protein called keratin. This is the same kind of protein that makes up the nails and the outer layer of skin.

• Each strand of hair consists of three layers. The innermost layer or medulla is only present in large thick hairs. The middle layer known as the cortex provides strength and both the color and the texture of hair. The outermost layer is known as the cuticle, which is thin and colorless and serves as a protector of the cortex.

• Chemical hair straightening and permanents (perms): Both relaxing and permanent waving utilize fairly strong chemicals that are applied directly to the hair shaft. While a perm is designed to add curls or waves, a relaxing treatment is designed to remove them. Hair texture and curl is determined by the arrangement of sulfide bonds in each strand. The arrangement of sulfide bonds is largely a product of genetics, although environmental factors such as humidity may also affect the hair. Chemical hair straightening and perms alter the number of sulfide bonds in a strand of hair, thus rendering a look of more or less curl.

• Hair coloring: Hair colorings affect different parts of the hair. Temporary hair dyes simply coat the individual strands of hair, and wash out within a week. Semi-permanent dyes penetrate the strands of hair and bond to keratin. Permanent dyes penetrate to the core of the hair strand, and often make their way into the hair follicle on the scalp.

• Hair straightening with heat (thermal hair straightening): In this treatment, dry or semi-dry hair is held up against a heat source, normally a hair iron. The treated hair will remain straight for a period of hours or days. This procedure also dries the hair, and may result in broken or split ends. This procedure usually involves no chemicals.

• Henna hair dye: Henna is a mixture of natural dyes from plants, lemon juice, and water. The dye is rubbed into the hair. In this process, the dye molecule penetrates past the outside layer of the hair and bonds to the keratin molecules on the inside of the hair. Because this process occurs on the microscopic level, the result is an overall change in hair color. Many people prefer this process because the smell is not as adverse as commercially available products.

• Highlighting: In this method, the entire head of hair is not treated. Instead, dye is only applied to particular parts of the hair, which is separated, usually by aluminum foil.

• Japanese hair straightening: Chemical hair straightening makes fuzzy, curly, unmanageable hair appear soft and silky. This technique was originally developed in Japan for clients who wanted to smooth out their wavy, unruly hair. Japanese hair straightening uses chemicals similar to chemical hair straightening; however, this particular procedure takes extra care to apply chemicals that avoid the normal side effects of dry, brittle hair. It is a permanent treatment, which means the hair will not revert to its original texture. It will be straight until it grows out or is cut off.

• Shampoo and conditioner: These products work to remove grease residue produced by hair follicles. However, nearly every shampoo and conditioner now includes a variety of other scents and chemicals.

Safety

• The Cosmetic, Toiletry, and Fragrance Association actively investigates the safety of cosmetic products. Furthermore, the Food and Drug Administration (FDA) investigates complaints of dangerous hair care products, even though the FDA does not regulate hair products. However, consumers should exercise caution when using any hair care product.

• Consumers should not assume that an "organic" label means that the use of the product may contain no health risk. Hair care products contain many chemicals, which may pose health risks, regardless of whether they were procured from organically grown plants.

• Testing cosmetic products on animals does not necessarily guarantee that the product will interact safely with the each human individual.

• Hair straightening and permanents (perms) involve extreme heat and/or chemicals; both of these processes have been known to cause damage to the hair, hair follicles, and scalp if used frequently. The hair may burn or break. Treatments may damage the follicles themselves, and result in hair loss and premature thinning. Hair straightening involves either extreme heat or chemicals, both of which may cause damage to the hair and hair follicles. Hair straightening processes may leave an individual with burnt and thinning hair, hair follicle damage, hair breakage, and hair loss. Treatments may result in an aggravation of dandruff, or the development of a dry and flaky scalp.

• Many hair treatments are considered painful to the scalp.

• Caution is advised in children.

• Hair products may irritate open, sore, or bruised areas of the skin.

• Some hair products may cause blindness; dying one's eyelashes is not recommended. Hair products applied to the pubic hair may burn the external genital structures and skin in this area, resulting in permanent scarring.

• Studies have shown a connection between the frequent use of hair products and adverse events such as birth defects, frequent consumers of cosmetics should vigilantly monitor their health.

Author Information

• This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

1. Blackmore-Prince C, Harlow S, Gargiullo P, Lee M, Savitz D. Chemical hair treatments and adverse pregnancy outcome among black women in central North Carolina. Am J Epidemiol. 1999 Apr 15;149(8):712-6. View Abstract

2. Chemical Hair Straightening. 30 May 2006. www.hairstraightening.net

3. Cosmetic, Toiletry, and Fragrance Association. 30 May 2006. www.ctfa.org

4. Hair Straightening Process. 30 May 2006. www.clearleadinc.com

5. Henna for Hair. 30 May 2006. www.hennaforhair.com

6. The Effects of Hair Straightening. 30 May 2006. www.drpistone.com