Harvey M. Fishman, Consultant
Harvey Fishman has a consulting firm located at 34 Chicasaw Drive, Oakland, NJ 07436, email@example.com, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.
All of these hairs originate in a follicle that is located about an eighth of an inch down in the layer of skin below the epidermis that contains blood and nerves. The hair follicle can be considered a tiny hair factory that operates 24 hours a day, seven days a week for several years, shuts down for a rest period and then starts producing again. The growth phase is the anagen phase, the transition phase is the catagen phase and the rest phase is the telogen phase. As many as 75 scalp hairs are lost each day, and an individual hair can last from two to six years before it is shed. It has been determined that feminine hair usually lasts about 25% longer than masculine hair, although armpit hair longevity is about equal in men and women.
A child may have short, soft hair called vellus covering his body. At puberty, the follicles stop producing vellus and begin making coarse adult hair. Eventually, with age, the follicles may degenerate to produce vellus hair again, or shut down completely. This process is responsible for ordinary balding which occurs to men about midlife, but to relatively few women.
Hair is made up almost entirely of protein called keratin, which has an outer layer of protective overlapping cells (the cuticle) that resembles roofing shingles. The middle layer, or cortex, is an elastic material that gives hair its resilience and flexibility. It is possible to stretch hair its own length, and to have an individual hair support a 3oz. weight. The cortex also contains melanin, the pigment that determines hair color. In the center of the hair is the medulla, which resembles bone marrow. It may be continuous, discontinuous, fragmented or not present in some hair shafts. Scientists are not sure of its exact function except that it contributes bulk to the hair shaft. The sebaceous gland supplies a lubricating oil (sebum) to the hair to make it look lustrous and healthy, rather than dry and brittle.
The hair above the scalp is dead. The production rate of individual follicles in the body varies. For example, follicles affecting eyebrows and eyelids rest most of the time but scalp follicles produce about half an inch of growth a month. Beard hair grows slightly faster. Although a woman has the same number of follicles as a man, the hair produced is very different. Her body and facial hair is mostly a fine, almost invisible down—the same vellus hair that a man has as a baby.
Follicles produce hair that is straight, wavy or curly. Looking at a cross-section of a hair might show it to be round, oval or flattened. Round is for straight hair, oval for wavy, and flattened is for kinky hair with degrees in between. The flatter the hair is, the curlier it is; the rounder it is, the straighter.
Hair can be affected by diseases and can be used to detect chemicals consumed, especially metals. Forensic chemists may perform analytical tests on hair to determine if a body was fed arsenic or how much lead was inhaled from industrial pollution. DNA analysis is also performed.
In our industry, the state of the cuticle and cortex, both physical and chemical, determines the condition of the hair and impacts its ability to be colored, conditioned or waved.