There are many approaches to temporary body hair removal including shaving, epilation/electrolysis, depilation, waxing, plucking and other therapeutic anti-androgen/enzymatic treatments. They all have general advantages and drawbacks. For instance, shaving requires continuous hair removal and can lead to skin irritation from abrasion. Epilation removes the entire hair shaft from the root for long-term hair removal but can be painful and can even cause scarring if not properly performed. Depilation is effective and provides extended hair reduction but due to its high pH, is potentially irritating. Waxing and plucking do not effectively or completely remove hair and can be painful. Finally, anti-androgen and enzymatic treatments require proper timing, i.e. within the hair cycle stage, to provide long-lasting hair removal.
There are also permanent approaches to hair removal that target and destroy the mechanisms regulating hair growth, including electro-epilation, photo-epilation and ultrasound-epilation. In addition, the thermo-laser approach heats hair follicles pretreated with a specific black-colored solution that, once heated, destroys the hair, resulting in the long-term retardation of hair growth. Although some permanent approaches to hair depilation can be effective, this column will focus on creating personal care formulations for the temporary depilation of hair.
Key Components of Hair Depilation
The key chemical necessary for hair depilation is based on an alkaline reducing agent that disintegrates the disulfide bonds (S-S) formed between cysteine units of keratin molecules in hair; this allows for the easy removal of hair by washing the skin surface. This depilatory action allows for the formation of new disulfide bonds (e.g., thioglycolic acid). This reaction is shown in Figure 1 on Page 24.