With clinical input from Hanan Mourad, Co-Founder and Head Educator at Aesthetic Equipment Australia and ABIC board member for the electrolysis sector.
The short answer
In thermolysis, the radio frequency a machine runs at changes how its energy spreads around the probe tip. Silhouet-Tone describes 27.12 MHz as the most concentrated of the three, suited to very fine and fine hair. It describes 13.56 MHz as carrying the most power, for very coarse and complex hair, and 6.78 MHz as spreading widest and most gently, for medium and coarse hair and for clients who feel the other two.
Most professional epilators sold in Australia run thermolysis at one fixed frequency. The Silhouet-Tone EVO XHD, distributed in Australia by Aesthetic Equipment Australia, runs all three. The operator picks the frequency to suit the hair, instead of working around the one the machine was built with.
Electrolysis is permanent hair removal. Laser and IPL are permanent reduction. That difference is why electrolysis still gets the hair other methods leave behind.
What frequency actually does in thermolysis
Thermolysis sends a high-frequency alternating current down the probe. Moisture in the tissue around the tip heats up, and that heat coagulates the cells that grow the hair. Frequency is how fast the current alternates, measured in megahertz (MHz).
All three frequencies discussed here alternate millions of times a second, so speed alone doesn't separate them. What an operator notices is where the heat goes: how tightly it gathers at the tip and how far it reaches into the follicle.
Galvanic works on a different principle. Direct current produces lye (sodium hydroxide) in the follicle, which destroys the growth cells chemically. Blend runs galvanic and thermolysis together. Frequency choice applies to thermolysis and to the RF side of Blend, and not to galvanic.
The three frequencies side by side
Each frequency has a job it does well and a trade-off that comes with it. The descriptions below are as stated by Silhouet-Tone.
| Frequency | How the energy behaves | Strongest on | Trade-off |
|---|---|---|---|
| 27.12 MHz | Concentrates closest to the probe, with the narrowest spread of the three | Very fine and fine hair, where precision matters more than power | Less power in reserve for a stubborn follicle |
| 13.56 MHz | Carries the most power of the three, with stable spread through resistant tissue | Very coarse, extra coarse and complex hair | The least forgiving of an insertion that is slightly off |
| 6.78 MHz | Spreads widest and deepest, at a slower pulse and softened intensity | Medium and coarse hair, and clients who feel the other two | Broader influence zone, so less suited to very fine work |
None of the three is the best frequency overall. A higher number doesn't mean a stronger treatment. 27.12 MHz is the most concentrated, but 13.56 MHz carries the most power.
What Australian clinics are working with
Most electrolysis machines on the Australian market run thermolysis at one frequency. That includes the widely used Sterex and Apilus units, and every Silhouet-Tone and Clareblend device except the EVO XHD.
| Device | Thermolysis frequency |
|---|---|
| Sterex SX-B | 13.56 MHz |
| Apilus Senior 3G | 13.56 MHz |
| Apilus xCell Pur and xCell Pro | 27.12 MHz |
| Clareblend Essence | 13.56 MHz |
| Silhouet-Tone ST350 Evolution | 6.78 MHz, with Vector Modulations |
| Silhouet-Tone EVO XHD | 27.12, 13.56 and 6.78 MHz, with Vector Modulations |
Silhouet-Tone launched the EVO XHD in August 2024. The manufacturer describes it as the first electrolysis device to combine all three frequencies in one machine.
Every machine in that table does good work in the right hands. On a single-frequency unit, an operator who wants a different energy profile changes the probe, the intensity, the timing or the modality. Experienced electrologists do that every day. A choice of frequency gives them one more setting to work with, and it's the one a single-frequency machine can't change.
Matching the frequency to the hair in front of you
"Whilst the machine will give you preferred presets for the treatment, it also gives you the capability to override these preset frequencies, allowing you to manipulate the device however you like."
Hanan Mourad, Head Educator, Aesthetic Equipment Australia
Fine facial hair
Fine hair on the upper lip, cheeks and chin needs precision more than power. That's where 27.12 MHz fits, because it keeps the energy close to the probe.
Coarse, deep and hormonal hair
Clients with hormonal hair growth, including those with PCOS, often arrive with coarse, deep-rooted hair on the chin, jaw and neck. Many have spent years waxing or threading, which can leave follicles distorted or curved. 13.56 MHz carries the most power of the three for this kind of hair. Galvanic and Blend remain the usual choice for a badly distorted follicle, because the lye reaches into curves that heat alone may not.
It helps to set expectations at consultation. While hormones keep driving growth, new hairs can keep appearing, and the client may need referral to their GP alongside treatment.
"With PCOS clients, the most important conversation happens before I pick up the probe. They need to know hormones can keep producing new hair, so we plan for ongoing treatment, and I'll often suggest they see their GP as well."
Hanan Mourad
Medium hair and sensitive clients
6.78 MHz spreads its energy wider and more softly. Silhouet-Tone recommends it for medium and coarse hair, and for clients who find the other two frequencies uncomfortable.
Work that arrives after laser and IPL
Laser and IPL depend on pigment in the hair, so white, grey, blond and many red hairs respond poorly. Some clients also develop paradoxical regrowth, where hair growth increases near a treated area. Those clients end up at an electrologist. The EVO XHD has named programs for IPL and laser post-treatment clean-up, paradoxical regrowth, ingrown hair and distorted follicles. A clinic running laser at volume can keep that finishing work in house instead of referring it out.
"A lot of my electrolysis clients come to me after a laser course. Usually it's the grey and blond hairs that are left, or regrowth they didn't expect. I run laser in my own clinic, and I wouldn't run it without electrolysis in the next room."
Hanan Mourad
Comfort settings: Vector Modulations and Tolerance
Vector Modulations is sometimes mistaken for a fourth frequency, but it isn't one. It changes the shape of whichever current you've already chosen, breaking it into decreasing segments a thousandth of a second long instead of holding it steady. It works on thermolysis and the RF side of Blend, and not on galvanic.
Tolerance steps the intensity back for a client who is feeling the treatment, without rebuilding the program. On a long session with a nervous client, that saves the operator from starting over every time the client flinches.
When one frequency is enough
A three-frequency machine won't suit every clinic. If most of your book is straightforward work a few hours a week, you won't use most of what the EVO XHD carries.
For everyday treatment, the Silhouet-Tone ST350 Evolution runs galvanic, thermolysis and Blend at 6.78 MHz with Vector Modulations, for considerably less. The EVO XHD makes sense once the difficult cases are already coming through the door: post-laser clean-up, paradoxical regrowth, distorted follicles, and clients across Fitzpatrick I to VI on every hair calibre. It also suits multi-therapist rooms that need presets anyone on the roster can rely on.
"I'd rather a clinic buy the machine it will actually use. If the book is mostly straightforward work, the ST350 will do that job well, and the difference in price is better spent elsewhere in the business."
Hanan Mourad
Silhouet-Tone EVO XHD at a glance
The EVO XHD sits at the top of the Silhouet-Tone range, with nothing above it.
| Feature | EVO XHD |
|---|---|
| Frequencies | 27.12, 13.56 and 6.78 MHz |
| Modalities | Galvanic (DC), thermolysis (RF), Blend |
| Thermolysis modes | Super Flash, Flash, Slow Flash, Pulsed Flash |
| Blend modes | Short, Soft, Pulsed, Uni |
| Programs | 1500+, covering 21 body and 15 facial zones across six hair calibres, all adjustable |
| Specific modes | IPL and laser post-treatment, paradoxical regrowth, ingrown hair, distorted follicles |
| Comfort | Vector Modulations and Tolerance |
| Assessment | Hydration test before treatment |
| Operation | One foot pedal, or hands-free Autosense with adjustable insertion delay |
| Phoresis | Cataphoresis (+) and anaphoresis (−) |
| Interface | 10.1 inch touch screen with stylus |
| Origin and certification | Made in Canada; CSA, FCC and CE |
| Warranty | 2 years on the device |
| Training | Included, in person |
Flash is thermolysis at high intensity, timed by the device instead of the operator. It isn't a separate modality.
Training that comes with the machine
Every EVO XHD comes with in-person device training led by Hanan Mourad. See what device training includes.
Device training teaches you the machine. It is separate from a qualification.
Frequently asked questions
Is electrolysis permanent hair removal?
Yes. Electrolysis is permanent hair removal, because it destroys the growth cells of each follicle it treats. Laser and IPL are permanent reduction.
What frequency is best for electrolysis?
No single frequency is best for every hair. By Silhouet-Tone's description, 27.12 MHz suits very fine and fine hair, 13.56 MHz suits very coarse and complex hair, and 6.78 MHz suits medium and coarse hair and sensitive clients.
Is 27.12 MHz better than 13.56 MHz?
They do different jobs. 27.12 MHz concentrates energy more tightly, while 13.56 MHz carries more power. Which one suits a treatment depends on the hair and the client.
What is a three-frequency electrolysis machine?
It's an epilator that can run thermolysis at more than one radio frequency, so the operator chooses the one that suits the hair. The Silhouet-Tone EVO XHD runs at 27.12, 13.56 and 6.78 MHz.
Can electrolysis treat hair that laser has missed?
Yes. Electrolysis doesn't rely on pigment, so it can treat white, grey, blond and red hair that laser and IPL handle poorly. It's also used for paradoxical hypertrichosis after laser.
What qualification do I need to use an electrolysis machine in Australia?
Check your state's requirements and your insurer's conditions before treating clients.
Who distributes Silhouet-Tone in Australia?
Aesthetic Equipment Australia, based in Arncliffe NSW, is the exclusive Australian distributor of Silhouet-Tone and Clareblend electrolysis devices.
About Hanan Mourad
Hanan Mourad is Co-Founder and Head Educator at Aesthetic Equipment Australia, the exclusive Australian distributor of Silhouet-Tone and Clareblend. She sits on the board of ABIC, the peak body for the Australian beauty industry, representing the electrolysis sector. She also owns and runs a dermal and laser clinic in Sydney, where she treats clients with both electrolysis and laser.
Hanan leads Aesthetic Equipment Australia's in-person device training.
Talk to us about your clinic
Tell us what your book looks like: the hair types, the post-laser work, how many operators you run. We'll tell you straight whether the EVO XHD or the ST350 Evolution suits the room, and arrange a demonstration.
Send an enquiry, book a call, email info@aestheticea.com or call sales on 0472 674 596.