What is the difference between thermolysis and blend and which method works best?

Posted on December 18, 2018 by Ellen Defrancq

There are 2 basic types of electrolysis hair removal that are still practiced today which we both use at 2pass Clinic. Basically, we always start with thermolysis and only switch to blend when we have no other options left.

Thermolysis hair removal

  • Thermolysis works more quickly than blend, taking less than a second per hair.

    Drawing of rabbit to illustrate that thermolysis works faster than blend

    Thermolysis hair removal works faster than blend, needing less than a second per hair.

  • Thermolysis uses alternating current that changes direction constantly. The electrons move back and forth along the conductor. You can think of the electrons of the water molecules alternately being pushed and sucked back. Friction from vibration is a phenomenon that resembles the heat generated by rubbing sticks together to start a fire. We use the best equipment on the market with 27Mh alternations. This means the current will change 27 million times of direction in a second. This will give less collateral damage and will be faster. All other machines on the market are 13Mh machines.

    Diagram of alternating current wave used for thermolysis hair removal

    Thermolysis hair removal uses Alternating Current. The Apilus machine of 2pass Clinic alternates 27 million times a second. The highest speed on the market.


  • The hair follicle is killed by heat caused by the friction that the quick alternation of current direction causes. Hence the name thermo-lysis.

    Drawing of a hair follicle where you see a man putting on a fire with sticks.

    Thermolysis hair removal kills the hair follicle by heat. Friction from vibration can be likened to the heat generated by rubbing sticks together to start a fire.


  • For reasons of speed, this technique is used most commonly for initial clearings at 2pass Clinic. In most cases we have very good results with this technique. We will switch to the blend when we clearly see distorted follicles or we feel we don’t have enough result with the thermolysis.

Blend electrolysis

  • Slower than thermolysis, needing 8 to 12 seconds per hair. This method takes five times longer – and by consequence is five times more expensive because you pay per hour.

    Drawing of a turtle to illustrate blend electrolysis hair removal is slow.

    Blend electrolysis hair removal is a very slow process needing at least 6 seconds per hair.


  • Blend electrolysis uses Direct Current that does not change direction.

    Graph showing direct current used in blend electrolysis.

    Blend electrolysis uses direct current that doesn’t change direction for hair removal.


  • The patient has to hold the positive pole, or a pad is placed under the shoulder to close the circuit.

    When the blend electrolysis method is used, the patient holds the positive pole in her hands.


  • Blend electrolysis kills the hair follicle by means of a chemical process instead of heat. Your skin contains a lot of salty water, and when a direct current is applied, a chemical reaction takes place within the skin splitting the water molecules (this is the real meaning of electro-lysis, in the strict sense of the word thermolysis is no electrolysis but people do use it for thermolysis as well). Those split water molecules will react with the salt molecules and will form a new substance (caustic soda or lye), which is highly caustic and will destroy the hair follicle. This chemical action is not instantaneous but takes time to develop in the follicle. It also does not stop when the current ceases to be applied, it continues for a very short time afterwards.

    Diagram of direct current electrolysis applied to salt water

    Blend electrolysis causes destruction by the chemical formation of NaOH (lye). The direct current splits the water molecules which will react with the salt molecules present in the body.


    Drawing of a hair with a caustic warning signal in it to indicate blend kills the hair by a chemical caustic reaction.

    Blend electrolysis hair removal kills the follicle by a chemical reaction.


  • Blend electrolysis is more effective than thermolysis on curly hairs.  This because the caustic lye is fluid and can glide into the curve.

    The caustic soda of the blend reaction is fluid and can find his way behind the curve.


  • At 2pass Clinic An initial clearing is simply impossible with blend as you would need 16 days at least. Cleaning up of stubborn hairs is what we mainly use the blend electrolysis for. We also switch to blend if we see clearly distorted follicles.

Want to see what happens inside a follicle with thermolysis vs blend electrolysis?

Which method is the best? Thermolysis or Blend electrolysis hair removal?

We often hear our patients say that blend is more effective than thermolysis. This is at present a myth. Until the 1990’s this claim was correct. It wasn’t until the 1990’s that scientist discovered the stem cells, responsible for the regeneration of the hairs, where not located at the bottom of the follicle but in the upper one third in an area called the bulge.

Drawing of a hair follicle illustrating the location of the Bulge where the stem cells are and the bulb at the bottom.

For electrolysis to be effective only one thing has to be done: kill the stem cells responsible for hair growth. These are located in an area called the Bulge in the upper part of the follicle.

The reason why blend worked better is that the chemical reaction starts simultaneously over the whole length of the probe, while thermolysis starts at the tip of the probe. The blend killed the bulge with stem cells avertedly in the process, not even knowing they existed.

Drawing of two probes with the indication of activity only at the tip and one showing activity over the whole length

Thermolysis (left) starts at the tip of the probe. Blend (right) start immediately over the whole length of the probe.


Since the discovery of the stem cells, electrologists have adjusted their technique and moved the probe in the follicle to the correct location to kill the stem cells with thermolysis as well.

Read more on electrolysis hair removal


You still have another question? Feel free to ask! We will answer your question and if generally applicable add it to the FAQ of this page.

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