COSMETICS AND BATHROOM PRODUCTS:HAIR GROWTH PRODUCTS

HAIR GROWTH PRODUCTS

Hair growth products first appeared in Japan in the 1950s, but not until 1979 was the first U.S. patent issued for a treatment for male baldness. In the 1980s, the market for these products developed extensively, and demand in the United States for these types of products continues to rise among both men and women.

Hair growth on the scalp and forehead of humans develops around the second month of fetal life. In the bottom basal layer of the epidermis, the primitive hair germ is formed. As the hair germ lengthens, the base of the hair follicle, also composed of epidermal cells, extends and surrounds mesenchymal cells of the dermis to form what is called the der- mal papillae. Hair matrix cells (also epithelial cells) formed within the follicular base then proliferate and differentiate to grow into actual hair. Around the fifth month of fetal life, the follicles on the scalp continue to grow, while those follicles that supported hair growth on the forehead regress. The continual process of hair growth and loss involves a hair growth cycle that includes specific follicular stages of growth activity, intermedi- ate regression, and resting (termed the anagen, catagen, and telogen phases,

respectively). Hair that has ceased to grow during the telogen phase falls out naturally. Hair repeatedly grows and falls out in accordance with the hair cycle in a normal scalp, yielding approximately 90 percent of follicles in the anagen phase and 10 percent in the telogen phase at any given time. However, many biochemical and environmental factors may dis- rupt the normal hair cycle. If these factors shorten the anagen (growth) phase, they cause the hair to become fine and downy vellus hair resem- bling infantile hair called lanugo. This situation is typically manifested with the condition called male pattern baldness and can be exacerbated by the androgen hormone testosterone. When testosterone is converted into the more potent androgen dihydrotestosterone, it may then bind to hair follicle receptor target cells and initiate a cascade that accelerates hair loss. Should factors cause the telogen phase to lengthen, the result is the loss of a considerable amount of hair without immediate replacement. The scalp then becomes thin and noticeable balding results, as is the case with female pattern baldness (also called diffuse baldness). While de- creasing mental stress and improving one’s diet may assist in alleviating hair loss, many hair growth products often use active agents that increase cell viability, elicit antiandrogenic agents, inhibit the secretion of follicle- deteriorating sebum, and/or accelerate blood flow. A blood flow acceler- ant marketed in the United States and Europe as a hair growth agent is minoxidil. First introduced as a medicated treatment for high blood pressure (called an antihypertension drug), minoxidil acts by dilating blood vessels based on cellular potassium channel-opening action. As a secondary effect in many patients prescribed the drug, it was shown to produce a growth of hair anyplace on the skin containing hair follicles. While the specific mechanism of this hair growth promotion is unclear, minoxidil was approved by the Food and Drug Administration (FDA) in 1996 as an over-the-counter drug. Regular-strength hair regrowth treat- ment for men and separately marketed hair regrowth treatment for women each contains 2 percent minoxidil as an active ingredient. Extra- strength treatments for men contain up to 5 percent minoxidil. Inactive ingredients in these products include alcohol, propylene glycol (emulsi- fier), and purified water. While women’s treatments are designed to re- grow hair on the scalp, men’s treatments are only designed to regrow hair on the top of the scalp, not for the treatment of frontal baldness or receding hairline. Used twice daily, product results may occur for some consumers within two to four months. Hair loss is usually manifested again with discontinued use.