Density: monopolar and bipolar RF, delivered in sequence

Radiofrequency is not light. It is current. A laser works because a target absorbs a particular wavelength; radiofrequency works because tissue resists the current passing through it, and that resistance generates heat inside the tissue itself. Nothing is burned at the surface to warm what lies beneath — the heat is made in the layer being treated.

Above a certain temperature collagen denatures and contracts, and the body reads that change as an injury worth repairing. Two things are therefore expected, on different clocks: immediate contraction during the pass, and remodelling over weeks to months. The first subsides quickly; the second is what lasts. This is why the face you see the morning after tells you very little.

One distinction decides whether this is the right treatment at all. Injectables and energy devices work on different layers. Injectable boosters put material into the dermis or prompt the skin to make its own; density, texture and thinning are their territory. Radiofrequency lifting applies heat to the structure below, and laxity is its. "My skin has gone thin" and "my jawline has lost its edge" are different complaints needing different tools, and patients often have both — in which case the two are sequenced rather than combined blindly. Our comparison of six collagen boosters covers the injectable side.

"It uses both" is the sentence you will see most often about this device, and on its own it explains nothing. The difference is a question of where the current goes.

Monopolar — the current travels through the body

A monopolar handpiece carries a single electrode. The tip emits current, which passes through the body to a return pad placed elsewhere on the patient. Because the current crosses tissue to get there, it reaches deep and spreads widely — layers well below the surface are heated along with those near it.

Bipolar — the current stays within the tip

A bipolar tip carries two electrodes side by side. Current never travels through the body; it takes the short path from one electrode to the other. The heated field is therefore shallower and narrower, but far more predictable in where it lands. As a general principle of the mode, depth of effect is governed largely by electrode spacing.

Why one after the other

The two modes are not substitutes. They are responsible for different depths. The deep layer requires monopolar; the superficial layer, treated within a controlled field, requires bipolar. A device offering only one leaves the other outside its range.

Density emits both in sequence within a single delivery, and the manufacturer describes this sequential heating as its patented technology. The intent is to treat different depths continuously in one pass, rather than switching handpieces or splitting the treatment into separate passes.

Any honest account of radiofrequency lifting has to put burns first. Heating tissue is the entire purpose of the device, and that purpose is also the source of the risk.

The problem is not temperature as such but where the temperature arises. Heat is wanted in the dermis and below, yet the current enters through the epidermis — and if the epidermis heats along with the target, that is a burn. Nearly every design decision in an energy device serves one problem: heat the depth, cool the surface. Density's safety hardware is its answer to that.

Gas cooling — taking the surface temperature down

Density cools the epidermis with gas cooling. Holding delivered energy constant while lowering surface temperature pushes the point of heat accumulation deeper. Cooling is adjustable across five levels, because skin thickness and sensitivity differ by site — the periorbital setting under the jaw, or the reverse, is not a sensible way to treat a face.

RIC — correcting for impedance that varies by site

Heating is not determined by output alone. Tissue impedance works alongside it, and impedance is not uniform: it shifts with skin thickness, hydration and subcutaneous fat, and differs between the forehead and the cheek of one face. Pass over all of it at a fixed setting and some areas receive too little, others too much. RIC reads that variance and adjusts output to match. The purpose is not to deliver more energy but to deliver less variance.

Real-time temperature — so nobody has to guess

Skin temperature is displayed during treatment, so the operator adjusts against a number rather than feel and experience alone. Worth stating precisely, though: what is measured is surface temperature, not the heating actually occurring at depth. A genuinely useful signal, but not a complete one.

The tip is both a consumable and the point at which energy crosses into skin. Sites differ in the area and access they require, so tips are separated by purpose. Density has four.

Rated shots is how many deliveries a tip is good for before replacement — a consumable specification, unrelated to treatment intensity or result. The Face Tip's higher count does not mean the face is treated harder; it means the area is larger.

How many shots a session uses depends on the area treated and the skin's condition. A larger number is not a better outcome, and passing repeatedly over the same area raises the risk of a burn rather than the quality of the result.

Worth considering if

• A softening jawline and cheeks that have dropped are your main concern
• You do not want surgery and want minimal interruption to normal life
• Injectables have addressed texture and density, but the laxity is still there

Where Density alone will not get you there, or is not appropriate

• Hollowing of the cheeks or temples — radiofrequency creates no volume
• Thin skin and broken-down texture as the main problem — injectables come first
• A large amount of genuinely excess skin — beyond what any non-surgical device does
• An implanted electrical device such as a pacemaker or defibrillator — radiofrequency passes current, so this is avoided in principle
• Metal implants at the treatment site — tell us beforehand
• Pregnancy, or infection or active skin disease at the treatment site
• Skin still recovering from recent aggressive thermal treatment in the same area

This list does not replace a consultation — medication and underlying conditions change the assessment, so please tell us about them.

Evidence for Density itself

Within the material we were able to search, no published clinical trial results specific to Density could be found. That is why this page makes no claim that the device is "clinically proven" and gives no figure for how many months a result lasts. Where evidence does not exist, the better course is not to write as though it does.

Evidence for radiofrequency lifting as a technology

Evidence for a device and evidence for the technology are different things and should not be blended. Heating the dermis with radiofrequency to provoke a collagen response is long-established and has research behind it. One recent study is worth summarising, with the caveat first: it did not use Density.

The limitations — as the authors themselves stated them

A result should be read with the limitations its authors put in print. These were theirs.

• No randomised control group. A prospective, evaluator-blinded cohort study, not a comparison against untreated controls
• A small, all-female sample. Twenty participants, no men included
• No comparison against other anti-ageing technologies. The design cannot support a conclusion that this approach is better than another

So: there is evidence that monopolar radiofrequency produced measurable change under one set of conditions. That is not evidence for Density, not evidence about any other device, and not the evidence of a large randomised trial. Conflating the three is where a clinical page becomes an advertisement.

The consultation starts by separating the problem into laxity, density or volume. Radiofrequency lifting becomes a candidate when laxity is the dominant one.

Then we take a history: implanted electrical devices, metal implants at the treatment site, pregnancy, recent treatments, current medication. Those questions are not a formality here — they determine whether treatment goes ahead at all.

On the day, skin is cleansed and topical anaesthetic applied according to site and settings. The area is mapped, and output and cooling level set region by region: forehead, cheek, jawline and neck do not share conditions, so one setting is not carried across a whole face. During delivery heat rises and recedes in waves; because the epidermis is cooled, the surface does not stay hot throughout. The operator works from the temperature readout and from what you say you are feeling.

We prefer not to stack treatments into a single day. Where injectables or fillers are also planned, separating them in order and interval is safer. If you are already being treated with another energy device such as X-ERF or Oligio Kiss, we check the interval before proceeding.

Pain depends on site and settings — generally a brief pulse of heat, felt more sharply over bone and where skin is thin. The monopolar RF study cited above reported mean pain of 0.4/10, but that figure belongs to that study's conditions and individual thresholds vary widely.

Downtime is generally short; once the flush settles most people carry on as normal. Allowing a few days before anything important is still sensible, since redness can persist through the day.

• Cleanse gently with lukewarm water on the day; avoid sauna, strenuous exercise and alcohol
• Use sun protection diligently and moisturise well
• Postpone strong peels and exfoliation until the skin has settled
• If any area blisters or stays painful, do not rub or squeeze it — come back and let us look

This reference was written and reviewed by Dr. Lee Chi-Hak, director of Miso Clinic in Daegu, South Korea. The clinic keeps both energy devices and injectables and selects between them according to what a face is actually doing: devices where the problem is laxity, injectables where it is density and texture. References for our other radiofrequency devices are at X-ERF and Oligio Kiss, and the injectable side is compared in six collagen boosters compared. The full set is in our reference library.