Monopolar, bipolar or tripolar RF? What is best?

Monopolar vs bipolar RF treatment for skin tightening and cellulite removal
Skin tightening and cellulite reduction with monopolar, bipolar, tripolar, tetrapolar, octipolar and unipolar RF
What is monopolar radiofrequency treatment?
Deep treatment with monopolar RF
What is bipolar radiofrequency treatment and why is it so superficial?
Bipolar RF may feel strong, simply because it is superficial
Bipolar radio frequency with vacuum suction
Tripolar, tetrapolar, octipolar and other multipolar radio frequency
Why tripolar, tetrapolar and octipolar RF are pointless
Unipolar radio frequency treatment
Monopolar and bipolar RF options
If monopolar RF is so much better, why do bipolar machines exist?
How do I know what kind of RF treatment I am receiving, as a client?
Deep vs superficial RF treatment: important, but not the whole picture

Monopolar vs bipolar RF treatment for skin tightening and cellulite removal

There are different classifications of radio frequency treatment, depending on the different aspects of RF technology.

One important classification is based on the “active” poles (electrodes) that are used to treat the skin:

If only one electrode (electrical pole) comes in contact with the area to be treated, we have monopolar radiofrequency
If two one electrodes come in contact with the area to be treated, we have bipolar radiofrequency

On this article we examine the merits of bipolar vs monopolar RF and we also discuss the gimmicky tripolar, tetrapolar and octipolar RF treatments, as well as unipolar radiofrequency.

Book a treatment

Skin tightening and cellulite reduction with monopolar, bipolar, tripolar, tetrapolar, octipolar and unipolar RF

A very common question we are asked at the clinic is what is the difference between unipolar, monopolar, bipolar and multipolar (i.e. tripolar, tetrapolar/quadripolar, octipolar/octapolar) radiofrequency?

And which one is best for skin tightening and cellulite?

First of all, let's make it clear: there are only two poles in electricity: plus and minus. That's basic Physics from high school and everyday knowledge for anyone who does not live in a cave.

So all these names (tripolar, tetrapolar, octipolar, whatever-polar) are a misnomer and a little bit of a gimmick, especially when it comes to eight “poles”, which is overkill and unnecessary (more on that later).

But let’s first explain what is monopolar and bipolar, and then we will move to multipolar and unipolar.

As we will see below, the most important distinction regarding monopolar and bipolar is that monopolar radiofrequency treatment is generally deep while bipolar RF is generally superficial (but not always).

What is monopolar radiofrequency treatment?

In monopolar RF the (+) and (-) poles are located quite far apart from each other

As a result, the current has no other option but to traverse through ALL skin layers after entering the skin, travel through the body to the other pole, and exit there.

A split of a second later the polarity changes and the current is forced to go through all skin layers again on the opposite direction.

As the polarity changes a few hundred thousand to a few million times a second, ionic molecular vibration or water molecular rotation is produced (depending on RF frequency).

Both result in heat production.

Deep treatment with monopolar RF

The fact that the current is forced to go through all skin layers means that with monopolar RF (and depending on some other factors too) we can treat not only the skin surface (epidermis) but also the middle skin layer (dermis), the deepest skin layer (hypodermis/subdermis) and even the subcutaneous fat deposits and the fasciae below the skin itself.

In fact, radiofrequency is used in physiotherapy to heat muscles and joints. This application is specifically called shortwave diathermy, but it is still radiofrequency treatment.

As I mentioned above, how deep we treat with monopolar RF depends on some other factors too, not just on the bipolar vs monopolar arrangement.

However, in most setups monopolar RF generally allows us the opportunity to go quite deep.

Unfortunately this is not the case with bipolar RF, which is restricted to quite superficial treatment, no matter what gimmicks are used to make the current "go deeper".

This is the reason that we do not use bipolar / ”multipolar” RF at our clinic, even though our machine provides that option.

We don't even use bipolar RF for superficial treatment, e.g for acne, as we can fine-tune our machine to work superficially in a much better way than bipolar RF can ever do.

This is not to say that all monopolar radio frequency treatments are deep, but most are.

What is bipolar radiofrequency treatment and why is it so superficial?

With bipolar radiofrequency the plus (+) and minus (-) poles are located very close to each other - too close for deep treatment.

Because the (+) and (-) poles are close to each other (in some machines they are almost adjacent to each other), the current has no other choice but to briefly and superficially penetrate the skin - as little as one millimetre, i.e. the maximum depth of epidermis - and then exit the skin again from the other pole, not very far from where it entered.

Quite often the "trajectory" of the current spans just the surface of the epidermis, via the treatment product used (glycerol, cream, gel etc).

This means that if we want to properly treat the dermis, and even more so if we want to treat the hypodermis or the subcutaneous fat, we must first literally burn the epidermis, which sits in the way and absorbs almost all of the current.

Because nobody would ever want to burn their epidermis, treatment intensity is adjusted at lower levels.

This means weaker treatment, which keeps the epidermis happy but which also means that deeper skin layers receive very light, if any, treatment.

Bipolar RF may feel strong, simply because it is superficial

Epidermal heating gives the impression of a very strong treatment, with lots of redness, heat sensation, which indeed results in some superficial tightening.

However, not much collagen/elastin production is stimulated in the dermis/hypodermis below and definitely no cellulite fat (or subcutaneous fat reduction, which is located even deeper) ever occurs.

If intensity is increased, in order for the treatment to work on deeper skin layers (where collagen cells are found) and produce some skin firming/lifting, the epidermis is burned/irritated and/or severe pain is experienced. Hence some of these burn pictures and extreme pain stories in review websites.

If we try to move the two poles apart (say 4-5cm apart), treatment is a bit deeper, but still not deep enough, as most of the current still is driven through the shortest possible way from (+) to (-), which is on the surface of the skin via the contact medium used.

Indeed, the treatment product used in those cases (glycerol, cream, gel) carries its own impedance (electrical resistance) / conductivity (electrical permittivity), which results in superficial heating.

This in some machines, but not all, is counteracted by cooling, but still treatment remains fairly superficial with most applications of bipolar RF.

It is also quite pointless to use energy to heat the surface and then use more energy to cool the surface. This makes treatment weaker and not that deep, after all.

This is not to say that all bipolar radio frequency treatments are very superficial, but most are.

Bipolar radio frequency with vacuum suction

Then there is the option of vacuum suction to force the two poles to find themselves opposite each other, with a fold of skin in-between the poles, and thereby force the current to traverse all skin layers.

However, the current will still be driven mainly through the superficial layers and the contact medium with their low impedance, rather than go through two high impedance deep tissue layers to reach the opposite pole.

(Theoretically, if a low frequency (< 500kHz, low suction, bipolar machine is used with a low impedance treatment medium and with the two electrodes apart by 5cm, a good treatment could potentially be provided. But no such machine exists. I suggested such an arrangement to a machine manufacturer, but they were way making too much money by selling laser machines to be bothered to do it…)

However, the biggest drawback of vacuum suction for bipolar RF is that vacuum suction stretches the skin as well as the superficial veins, thereby resulting in skin looseness and/or spider/thread veins in many cases.

True, when treatment is provided by a well-trained, experienced and knowledgable therapist and combined with a good machine, even bipolar treatment can be deep enough and good for many applications, usually on the face.

But in general, bipolar RF, as compared to monopolar RF, is usually too superficial, even when vacuum suction and cooling are used.

Tripolar, tetrapolar, octipolar and other multipolar radio frequency

As I mentioned earlier, there are only two poles in electricity, plus and minus.

So the obvious question is how come a tripolar radiofrequency machine exists?

The answer is simple: with tripolar radio frequency, there are three electrodes, with the two poles (the plus and the minus), always alternating between the three electrodes. At any given time one of them is a minus, the other is a plus and the other is inactive.

So we do not have tripolar RF, we still have bipolar RF with the poles being alternated between three electrodes.

With tetrapolar RF, the two poles alternate between four electrodes, with two being inactive at any given time. With octipolar RF two poles are active and six inactive. And so forth...

Why tripolar, tetrapolar and octipolar RF are pointless

In theory, this alternation of poles results to more uniform and/or deeper heating. In practice, all we would need to produce deeper heating would be to move just two poles apart - we don't need all this “multipolar” gimmick. And in any case, we would still not go anywhere nearly as deep as with monopolar RF.

In regard to heating uniformity, multipolar arrangements are also pointless. With almost all RF treatments the therapist continuously moves the handpiece, which provides plenty of uniformity, without the need of so many "poles".

All in all, I find multiple poles a marketing gimmick. Of course the manufacturers of these machines would disagree.

But Physics is Physics. Monopolar means going through all skin layers, while bipolar means largely staying on the surface.

In nature, electrical current (or any other energy potential differential) will choose the easiest/shortest possible distance to travel. Basic Physics principle.

And you don’t need many electrodes to provide uniform treatment. Just move the handpiece.

Unipolar radio frequency treatment

Unipolar RF is neither bipolar nor monopolar - it is based on an electromagnetic field created by an antenna at the tip of the handpiece, which is applied on the skin.

Unipolar can be anything from medium superficial to medium deep, depending on cooling and other settings used.

Monopolar and bipolar RF options

Luckily, the better machines on the market offer two or more choices: monopolar or bipolar (or any of the varieties mentioned above).

If you are a practitioner and bought one of those machines, my advice is to just use monopolar. Focus on it, train on it and use it well, and it will be much better than any bipolar arrangement, even if you wish to offer very superficial treatment, as in acne treatment.

If you are a client, I would definitely advise you to go for monopolar. Some bipolar machines may work well for some applications, depending on the training and skills of the therapist, but in three words, "monopolar is king".

If monopolar RF is so much better, why do bipolar machines exist?

The reason is simple: cost. Monopolar machines need to employ higher intensities, as they heat the skin deeply.

This means bulk, heavy weight, no portability for home visits and high cost: you can't find a decent monopolar machine for less than £30,000, with the most expensive ones costing up to £90,000.

On the other hand, you can make a pretty cheap, small, light and portable bipolar/”tripolar” machine which also carries the name "radiofrequency machine” for as little as £1,000, while useless "home use" bipolar/”tripolar” machines can cost as little as £300.

Since the public does not know the difference and they think all radiofrequency machines do the same thing, you get the main motivation behind bipolar/”tripolar” machines.

Due to just superficial heating, even a cheap bipolar machine may in some cases appear to be very hot and powerful and impress the client, while in reality it is not powerful at all, and does not treat the deeper skin layers, where cellulite is found.

Obviously, you should not expect much in the way of results from those, either for your clients, as a practitioner, or for yourself, as a client.

How do I know what kind of RF treatment I am receiving, as a client?

The answer is very simple:

If a metal or a self adhesive pad is used to connect you to the machine (usually applied on your back), then you are having a monopolar RF treatment
If your only contact with the machine is the operator handpiece, then you are having a bipolar-type treatment (or, more rarely, a unipolar treatment)

Deep vs superficial RF treatment: important, but not the whole picture

Of course, depth of treatment is not the only important thing in radiofrequency, neither it is only affected by the arrangement of poles (there are several other variables that control depth of treatment).

And neither too deep a treatment is good, for various reasons.

But all these are important subjects that merit to be discussed in other, dedicated articles.