Process that destroys the hair by coagulating the papilla through heat

Process that uses intense light to destroy the growth cells of the hair bulb

Excessive growth of hair where it does not normally grow

Usually a caustic alkali preparation used for temporarily removing superfluous hair

Process of removing hair from the bottom of the follicle by breaking contact between the bulb and the papilla

Infected follicles or ingrown hairs from shaving or other hair removal methods, such as waxing

Ancient method of hair removal that uses water soluble solution that is easily removed, and is an alternative for clients with sensitive skin who react to waxing

Process of removing hair by means of electricity

Growth stage during which new hair is produced

Process of removing hair at or near the level of the skin

Process that destroys the hair by coagulating the papilla through heat

Transition stage of hair growth

Thermolysis method or Shortwave diathermy method or radio-frequency method - in this technique alternating current is passed through the needle which heats up the needle inserted into the root of the hair. A fine wire probe is used to transmit radio waves to tissues near the probe.Radio Frequency Diathermy (The therapeutic generation of local heat in body tissues by high-frequency electromagnetic currents) or Short Wave Electrolysis.  Molecules within the tissue are caused to vibrate which lead to a rapid increase of the temperature, causing coagulation (to change or be changed from a liquid into a thickened mass: egg white coagulating when heated; blood clotting over the wound) of the proteins within the follicle, effectively killing the follicle. The heated needle produces bubbles of the water which loosens the root and kills the germinative cells of the hair root to produce removal of the hairs.

This method is less effective then the Galvanic method. Thermolysis was developed in the 1920s and first reported in medical literature by Henri Bordier. A thermolytic epilator is essentially a radio transmitter, usually with an output of about 0-8 watts at a frequency of 13.56 MHz. RF energy emanates from the probe tip to tissue within about a millimeter. Thermolysis works by heating the hair matrix cells to about 48°C (118.4° Degree Fahrenheit), causing electrocoagulation. In this method, passage of a high-frequency current down the needle produces destructive heat in the follicular tissues by molecular vibration. This heat then destroys the hair structure and dermal papilla. Thermolysis is much faster than galvanic electrolysis and requires only a few seconds. In high-speed “flash” thermolysis the higher energy current is applied for only a fraction of a second. The flash method is best used with insulated needles, which protect the upper hair follicle and permit higher energy directly into the lower follicle. This method is not suitable for coarse hairs and may have a slightly higher risk of skin damage.  

Thermolysis has a circle of injury due to heat around the hair follicle that has been treated. If the large number of hairs are treated which are in close proximity, it will lead to overlapping the circle of injury around the hair follicle leading to the damage to the skin and scarring. Below is the figure demonstrating the circle of injury and the overlapping injuries leading to scarring.

Diagram depicting the Circle of injury to the skin around the hair follicles,

and overlapping circle of injury leading to skin damage and scarring

if the treatment is done in close proximity to each other

 The technique of thermolysis works with direct contact with the hair root. In case the needle is not able to touch all around the hair follicle it will lead to recurrence. The diagram given below depicts the missed insertions that can take place with thermolysis technique. To overcome this some electrologists rotate the needle so that it touches all around the follicle during the thermolysis. 

The Diagram depicts the missed insertions that can occur during electrolysis leading the recurrence of the hair growth

Another concern with thermolysis is the effect of heat on the skin causing premature aging due to damage of the collagen in the skin. (References 1 to 3 given at the end of this page)

The video below depicts the mechanism of Electrolysis - All the three technqiues - Galvanic, Thermolysis and Blend

References:

1.Kligman AM, Peters L. Histologic changes of human hair follicles after electrolysis: a comparison of two methods; Cutis. 1984 Aug; 34(2):169-76.
   (Abstract: The histologic changes induced by thermolysis of hairs of the scalp and legs were studied by light microscopy. Two techniques were compared on opposite    sides: conventional thermolysis (erroneously termed electrolysis) using bare needles and a newly designed precision epilator using an insulated, bulbous-tipped probe. Thermolysis generally did not immediately eliminate the papilla and hair matrix. Thermal injury provoked an inflammatory reaction which eventually destroyed the hair bulb. The insulated probe produced greater damage to the peribulbar tissue below and less necrosis of the perifollicular dermis above, enhancing the likelihood of permanent epilation and reducing the probability of scarring. The infundibulum and associated sebaceous glands regenerated to near-normal architecture. The lower follicle was replaced by a fibrotic streamer--a scar.)

2. Cho S, Shin MH, Kim YK, Seo JE, Lee YM, Park CH, Chung JH. Effects of Infrared Radiation and Heat on Human Skin Aging in vivo. Journal of Investigative Dermatology Symposium Proceedings (2009) 14,15–19; doi:10.1038.
(Abstract: Sunlight damages human skin, resulting in a wrinkled appearance. Since natural sunlight is polychromatic, its ultimate effects on the human skin are the result of not only the action of each wavelength separately, but also interactions among the many wavelengths, including UV, visible light, and infrared (IR). In direct sunlight, the temperature of human skin rises to about 40 degrees C following the conversion of absorbed IR into heat. So far, our knowledge of the effects of IR radiation or heat on skin aging is limited. Recent work demonstrates that IR and heat exposure each induces cutaneous angiogenesis and inflammatory cellular infiltration, disrupts the dermal extracellular matrix by inducing matrix metalloproteinases, and alters dermal structural proteins, thereby adding to premature skin aging. This review provides a summary of current research on the effects of IR radiation and heat on aging in human skin in vivo.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 15-19; doi:10.1038/jidsymp.2009.7)

3. Kim DH, Lavoie A, Ratte G. et. al. Effect of 27-MHz Radiofrequency on Hair Follicles: Histological Evaluation of Skin Treated Ex Vivo. Dermatol Surg 2015;41:466–472 ·DOI: 10.1097/DSS.0000000000000324
(Abstract: BACKGROUND:A multitude of methods and treatments exist for cosmetic hair removal. Electroepilation is a commonly performed method of hair removal that is so-called "permanent"; however, there is a paucity of histological studies of the effects of radiofrequency (RF) on hair follicles. OBJECTIVE: This study aimed to observe the destruction of human hair follicles and surrounding tissue after the treatment with 27.12-MHz RF, with more attention paid to the thermal destruction of bulge and bulb/dermal papilla. METHODS: Human scalp specimens obtained during face-lift surgery were treated with 27.12-MHz RF. The probe tip was inserted into hair follicle, RF current was applied, and treated specimens were processed for histological analysis. RESULTS: Significant damages were observed on treated hair follicles. Thermal damage was lance-shaped and extended over several hundred micrometers (100-400 μm). The location of destruction areas varied, likely depending on the point of insertion of the probe. The epidermis remained intact.CONCLUSION: This study shows that the general mechanism of thermolysis is to generate damage to cells and tissues surrounding the insertion point of the filament. The results suggest that if the insertion point is close to the bulge region, there is a risk to destroy hair follicle epithelial stem cells.)

4.

Which method of hair removal destroys the hair papilla?

What is thermolysis method?

During which phase of the life cycle of hair does the hair disconnect from the papilla?

What is the process of removing hair by means of electricity?