Electrical permanent hair removal
Dr Catherine de Goursac explores how permanent hair removal using electricity has evolved over the last 140 years
The removal of superfluous hair by the electrolytic action of galvanic current began in 1875 when Dr Charles E Michel of St Louis Missouri, reported his findings to the medical profession. Galvanic electrolysis is basically a chemical process, the substance that is formed in the follicle, is sodium hydroxide (lye). This highly caustic procedure is an effective way to destroy hair, however the needle must remain in the follicle for three to 20 seconds depending on hair thickness.
Finding this modality too slow, Paul Kree, from New York, developed the “multiple-needle technique” in 1916. However, this technique is no longer used.
During the twenties, Dr Henri Bordier from Lyon France, developed a new method of permanent epilation using RF (radio frequency). This new method promised greater speed and better results over the galvanic method. The system became popular during the 1940’s.
The evolution of electrolysis produced the “blend” technique :
Henri E St Pierre of San Francisco—a pioneer in electrolysis—uses both galvanic and radio frequency for permanent hair destruction.
For difficult cases, such as coarse hair or distorted follicles, he uses a galvanic unit and when needed, a short wave unit for work rapidly.
His desire for combining the efficiency of the galvanic, with the speed of the high frequency method led him to investigating the possibility of blending both at the same time. The “blend’’ technique was born.
It was at this time that Arthur Hinkle, a service engineer for the General Electric X-Ray Corporation in collaboration with St Pierre, began work on superimposing the two currents. Their first unit was called “Electro-Blend”.
These older techniques were efficient however very painful.
The latest innovation in the development of permanent hair removal—“vectorial’’ technology —consists of modulated sequences that vary current intensities and time while the probe is inside the follicle. These modulations increase energy sent to the follicle while decreasing pain.
This technology deceives pain receptors by sending, for a very short duration, a very high intensity burst to the follicle, followed by downward cascading modulations that eradicate all hair growing cells. These modulations can be used with Thermolysis and combined techniques.
Permanent electrical epilation
For over 20 years, hair removal, using laser and intense pulsed light (IPL) has continued to improve and satisfy both users and patients.
Laser and IPL destroy pigmented hair in the anagen phase including hair that is not yet visible.
Electrical permanent epilation destroys hair in the anagen phase regardless of its colour
• Treating hair not suited for laser IPL: (red, white, grey or very fine hair).
• Treatment when laser/IPL is contraindicated.
• Completion of laser/IPL treatments: treats stubborn regrowth.
• Treatment of light or white hairs and darker skin.
• Correction of paradoxical hair growth problems.
• Treating areas contraindicated for laser or IPL.
• Treating all body areas, skin colour, hair, hair sizes and shape, men or women.
• Reduction of post treatment problems and precautions (sun exposure).
Electrical permanent epilation consists of inserting a fine disposable needle shaped probe inside the hair canal to precisely catheterise the pilo-sebaceous follicle, without piercing it, without bleeding, and without pain. The hair guides probe insertion.
The objective is to obtain selective coagulation of the pilo-sebaceous follicle by using low frequency vectorial modulations while avoiding damaging surrounding tissues.
The treated hair is removed without any resistance by using small forceps.
This technique ensures complete destruction of the hair growing cells located in the dermal papilla and in the bulge.
Since hairs must be treated individually, this technique is preferred for treating smaller areas and stubborn regrowth.
When electrical permanent epilation is carried out using galvanic current (direct current), it is applied to tissue using 0.7 mA intensity. An electrochemical action is induced producing destructive lye.
It has long been understood that the application of direct electrical current to a solution of salt water produces a reaction causing salt and water to break into their constituent parts. These parts quickly rearrange themselves to form an entirely new substance, sodium hydroxide (lye), hydrogen and chloric gas.
The newly manufactured lye remains in the follicle a few seconds, causing a chemical decomposition of the hair growing cells in the papilla and germinative tissue in the bulge.
Used alone, this technique is very slow and time consuming (requiring about 20 seconds for a medium size hair) as well as painful. Therefore, this method is no longer used.
A galvanic current does not generate any heat.
Thermolysis or thermo-coagulation current
Thermolysis—also called thermo-coagulation method—uses a high-frequency current (13.56 MHz is the frequency mostly used by manufacturers), constantly changing polarity to generate heat and destroy the hair follicle by electrocoagulation.
During thermolysis procedures, high frequency radio energy is emitted (mostly) from the tip of the needle probe, inserted into the hair follicle. The high frequency energy vibrates hair growing cell molecules. This energy field pushes and pull electrons back and forth, creating heat through vibration, to the level of permanent tissue destruction. This destruction is referred to as electrocoagulation.
The needle probe remains cold
Tissue protein inside the follicle coagulates, dries out and is destroyed
During thermolysis, two techniques are used according to hair size:
• Slower technique- 4/10th to 2 seconds.
• Tissue temperature: 53 C
• Intensity: low to medium.
• Efficient for medium to coarse hair.
• Rapid technique—flash technique: 1/10th to 2/10th of a second—super flash technique 1/100th to 9/100th of a second.
• Tissue temperature: 100 C.
• Intensity: high to very high.
• Efficient for fine and very fine hair.
The blend technique is a combination and simultaneous use of galvanic and thermolysis techniques.
This combination method alleviates the shortcomings of each technique, while bolstering its advantages. Minimum time is required to produce reaction in the follicle.
The high frequency current increases the efficacy of the galvanic lye production. The caustic effect is increased by heating lye.
The advantages of both technologies results from the union of both currents.
With new technologies, it is not necessary to use blend technique when working on fine, very fine and medium size hair.
The blend technique is useful when working on coarse and very coarse hair as well as distorted or curved follicles, stubborn regrowth and white hair.
This technique deceives pain perception by first applying a very high intensity impulsion in an excessively short time. The following impulsions are modulated in a vectorial pattern using a decreasing current intensity to destroy germinative hair growing cells.
The current shape and strength supports the highly effective use of 6.78 megahertz.
This method is used with thermolysis techniques (thermo-coagulation and thermo-desiccation) or with combined modulated currents (blend).
Vectorial technology is very effective with blend, enabling use of stronger intensities while reducing duration and pain detection (treatment is therefore more comfortable).
The 6.78 MHz frequency optimises current stability, safety, efficiency, and ease of use.
The most used frequency for permanent hair removal is 13.56 MHz, a reasonable choice considering high frequency at high levels, experiences an altered HF signal, sacrificing stability and results.
The needle holder cable is similar to an antenna with energy waves concentrating on the needle tip (peak effect).
The cable needs to be insulated and calibrated (according to length and resistivity).
That is why lower frequencies (6.78MHz) are preferred.
Different probes (needles) with different lengths and diameters are available (from one to five—one being the smallest and five the biggest):
• Insulated (for thermolysis technique).
• Non-insulated (for blend/combined currents).
Their size and shape will influence the electrical current flow and precision of insertion.
Probes are chosen according to depth and coarseness of the hair. (length and diameter).
Non-insulated needles are used with the blend technique to ensure sufficient lye production in the follicle, along the entire probe.
Once treated, hair is removed from the follicle, without any resistance using forceps (or tweezers).
To ensure safe depilation during treatment, never treat hairs closer than 3mm to each other.
Hair growing cycles
The hair follicle has intermittent activity. It produces an abundance of keratin within a few months or years, eliminating and renewing it after a certain period (cyclic activity proper to different areas)
Histologists divide the growth cycle into three stages : anagen (period of active growth), catagen (retrograde morphogenic transformation) and telogen (period of rest).
Hair on the body renews itself through cycles.
All hairs have their own cycles, shedding and replacing regularly. Old hairs in the telogen stage are replaced by new hairs in the anagen stage. Many successive hair stages co-exist.
The hair growth cycle varies from six months (for upper lips) to six years (for the scalp).
Within a same location, mosaic in nature, several hair growth cycles co-exist. This is why several sessions, at regular intervals, are needed to treat different areas.
Electrical permanent depilation of a complete area can take up to two years (one year actual plus one year maintenance treatments)
• Patient age.
• Methods used for previous hair removal.
• Hair growth, when hair first appears (hair growth cycle activity).
• Time between sessions (regular appointments).
• Duration of each session (patient tolerance and sensitivity), number of treated hairs (between 800 to 1500 hairs per hour for experienced electrologists).
Treatments performed during the anagen stage, are more successful.
Following treatment hair regrowth varies between patients. It can reach up to 30% when using high frequency currents (thermolysis), and 20% when using combined currents (blend).
New hair, depending on the patient, is more or less rapidly, in constant development. This may leave the impression that treatment is not permanent, so explaining the causes of hair regrowth reassures the patient of professional competence.
It is necessary to treat regrowth the usual way and to schedule regular maintenance sessions.
Factors which influence treatment results include how regular the treatment schedule is, what other depilation methods are used while following treatments, and the use of certain medications.
Patient consultation is a very important step in establishing confidence between electrologist and patient.
It should be used to:
• Gather patient information (skin and pilosity evaluation).
• Obtain medical information and identify general or local contraindications.
• Establish treatment protocol according to individual pilosity.
• Explain treatment procedures.
• Plan ideal treatment outcome.
Regardless of the technique being used, the treatment procedure remains the same, with current intensity and duration (timing) parameters being the only variables.
Treatment session time will vary according to patient pilosity, skin sensitivity and tolerance threshold. Patient budget and tolerance to prolonged periods of immobility are also factors.
We prefer working on hair previously shaved or depilated (a few weeks before treatment). Treatment session can last from 10 minutes to one hour and can be repeated weekly or monthly.
Whitening of the skin around the probe and minor scabbing disappearing within 24 hours can occur.
Scabs may appear that are difficult to disappear, with a longer healing time requiring healing cream.
Hyper or hypo pigmentation is possible but is quick to disappear.
Pain is a consideration. Prior to treatment, apply a numbing cream (or use cooling device). After treatment, if there is any redness-oedema, apply soothing or healing cream. For any folliculitis, use a local antibiotic treatment.
These side effects are caused mainly by using intensities that are too strong or too long in duration. They are also caused by to shallow or deep insertions.
Dr Catherine de Goursac is an aesthetic medicine expert. She is a member of the French Association of the Board of Aesthetic Medicine, a member of the board of directors of the FSMEA, general secretary of the French Association Anti-Aging and a member of the SFME. She has authored numerous scientific publications and published numerous works for the general public. W: degoursac.com; esthetiquemedicale.com