The quest for permanent hair removal goes back millenia; archeologist say that men shaved as far back as 20 thousand years ago, using sharpened rocks and shells. Societies all around the world use diverse hair removal methods, from sugaring to caustic depilatory creams. However, the hair eventually grows back and the procedure must be repeated endlessly.

The oldest method of permanent hair removal is electrolysis. It works as advertised for most consumers if done correctly, but it requires training and skill by the operator. A hair-thin probe is inserted into each hair follicle, and low-voltage electricity is applied, causing localized damage to the follicle and preventing hair regrowth. Proper insertion of the probe follows the natural opening of the follicle and does not penetrate the skin.

This method of hair removal has a proven track record of more than 125 years, and most studies show 90%-93% customer satisfaction with the results. However, it can be expensive if large areas are to be treated, and waiting while a technician attends to each individual hair in turn can be tedious. It can be moderately painful. If the technician is unskilled, permanent scarring can occur, and unsterilized equipment can spread skin infections.

The treatment may have to be repeated 3-4 times, both to redo follicles which were not destroyed after one treatment, and to catch follicles which were not producing hairs at the time of treatment and thus went unnoticed. Hair follicles are not always in an active growth phase; however, after a year or so, most follicles will have been treated. Because a majority of hair follicles are in a dormant, non-growth phase at any given time, treatment must be repeated at 2-3 month intervals to catch them all.

The term "needle-free electrolysis" is sometimes used to describe hair removal devices which function by passing electric current down the hair shaft to the follicle by a tweezer or a conductive patch. These systems are completely ineffective, as hair is a poor conductor of electricity.

Battery-operated home units are sold on at department stores, the Internet and on Ebay, usually for around $20. The most popular brand is One-Touch by Babyliss, though others are offered as well. From personal experience, I can testify that these units do indeed work, but a lot of practice is necessary. Consumers who try this option should be aware that despite the detailed and quite adequate instructions accompanying the units, there is a learning curve, and many people have found that performing electrolysis on themselves is too difficult to be worth the trouble. However, if you do decide to use this option, a pair of magnifying glasses and a good set of tweezers can make the procedure much easier.

Electrolysis has a long history, and many researchers were experimenting with electrical methods of hair removal as far back as the American Civil War era. The first workable electrolysis machine was invented by St. Louis ophthalmologist Charles Michel, who in published results of permanent hair removal with treatment by a battery-powered electrified needle in 1875. He had been using his device to treat ingrown eyelashes since 1869. This DC-current powered method is referred to as electrolysis or galvanic electrolysis because a chemical reaction in the hair follicle causes formation of sodium hydroxide, which damages the follicle. The chemical reaction is as follows : NaCl (salt) + H2O (water) + direct current = NaOH (sodium hydroxide) + Cl (chlorine) + H (hydrogen).

Subsequent improvements included a machine using multiple needles, invented by Paul Kree in 1916; and the use of AC current, called diathermy, which causes direct thermal injury to the hair follicle, reported in medical literature in 1924 by Dr. Henri Bordier. The latter method is also referred to as thermolysis, short-wave, high-frequency, and radiofrequency hair removal.

Minor improvements continued through the 1930s and 1940s. In 1948, Arthur Hinkel and Henri St. Pierre received a patent in 1948 for a combination method they developed, and 20 years later published "Electrolysis, Thermolysis and the Blend", which described their experiments with different hair removal techniques. "Blend" refers to the fact that blended methods often work better than just one method alone.

Further improvements included incorporating transistors and computerized controls, as well as insulated probes and sterile disposable needles. However, despite attempts to automate electrolysis equipment, the effectiveness and safety of electrolysis is highly dependent on the skill of the operator. Electrolysis professional organizations exist and set standards for member certification, but in many states, anyone is legally permitted to offer electrolysis services. Therefor it is important for anyone seeking electrolysis to get references beforehand.

Use of this hair removal method continued into the early part of the 20th century, when it was briefly eclipsed by X-ray hair removal, which was advertised as safe and painless. It should be noted that people in this era displayed a generalized, dangerous lack of knowledge about the dangers of radiation; shoe stores even featured x-ray machines to aid in shoe fitting!

After the X-ray fad ended consumers returned to electrolysis until the advent of effective laser treatment in the 1990's. These days, most hair removal is done by laser, but electrolysis is still useful for isolated hairs, and for pale hair which responds poorly to light-based treatment.