“TL;DR: In this article we explore the appropriate conductive media - gels, creams, serums, glycerol or oils - for radiofrequency (RF) and ultrasonic cavitation treatments, emphasising that the choice depends on the machine’s frequency and type. For RF, lower frequencies (300kHz–1MHz) rely on ionic currents and require high-water-content gels or creams to avoid excessive surface heating, though constant reapplication is needed as they evaporate. Creams with low fat content are preferable to oily ones, which resist RF currents and cause overheating. Serums evaporate too quickly to be practical, while glycerol or propylene glycol offer a compromise, though they can still overheat the skin. Oils or no medium at low frequencies risk burns due to electrical arcs. At higher frequencies (10MHz–5GHz), water-based products overheat the epidermis, making oils a better choice for deeper tissue treatment. Intermediate frequencies (1–10MHz) often use glycerol or glycol. For ultrasound cavitation, gels suit high frequencies (1–10MHz), while oils work at lower ones (30–300kHz). It is important to follow manufacturer guidelines to prevent burns or ineffective treatments. Overall, the treatment medium’s role is important in both safety and efficacy.”
Cream, gel, oil or serum: what is the best conductive medium for radiofrequency & ultrasound cavitation treatments?
Different frequency RF machines will require different contact media - and the same applies to ultrasonic cavitation
Radiofrequency at lower frequencies
RF treatment gels
Radiofrequency treatment creams and lotions
RF treatment serums
Glycerol and propylene glycol products for low frequency RF treatment
RF treatment oils
Radiofrequency treatment with no contact medium
Radiofrequency at higher frequencies
RF treatment gels and creams
Glycerol / glycol products for high frequency radiofrequency
RF treatment oil
RF treatment with no contact medium
Radiofrequency at higher frequencies
RF treatment gels and creams
Glycerol / glycol products for high frequency radiofrequency
RF treatment oil
RF treatment without contact medium
Radiofrequency at intermediate frequencies
Conductive gel for ultrasonic cavitation. What about oil, cream, lotion or serum?
Electro-mesotherapy effect with the combination of ultrasound/radiofrequency and a concentrated contact medium
In summary
Caution / Disclaimer
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Different frequency RF machines will require different contact media - And the same applies to ultrasonic cavitation
Many people enquire about what is the best gel, cream, lotion, oil or serum to use for both ultrasound cavitation and radiofrequency.
However, especially for radiofrequency the answer is not clear cut and depends on the type of machine used. If the wrong type is used, burns can occur, especially for radiofrequency treatment.
This article provides a guide of what type is generally needed for different RF/ultrasound frequencies and other variables, and it will also understand you how different types of RF work.
In all cases, please firstly and primarily follow your manufacturer’s instructions and do not deviate from them unless you understand the subject at depth.
Radiofrequency at lower frequencies
The lowest frequency machines (300kHz to 1MHz) are based on ionic currents creating heat in the deep tissues - and unfortunately on the skin surface too, depending on treatment medium.
In this case, gels or creams with high water content applied on the skin will pose little resistance to the electricity generated by the RF machine, so they will not heat up.
However, being composed primarily by water, gels and creams will evaporate with constant movement and heating, meaning constant gel or cream application will be needed.
RF treatment gels
Gels, being just water and thickener are generally unsuitable, as the dried up thickener will flake, creating a lot of mess.
Radiofrequency treatment creams and lotions
With creams, however, things are more complicated. Creams and lotions are an emulsification (mix) mix of water and oil, with lotions generally containing more water.
When water evaporates, due to heat and constant moving of the RF handpiece, we are left with oil, which is not absorbed nearly as fast as water by skin. This will indeed pose more resistance to RF currents and therefore it will heat up.
This means that unless we keep replenishing the cream/lotion we will have very high superficial heating. This defies the whole point of radiofrequency treatment, which is deep heating.
The solution is to use a low-fat / high-water content cream or lotion to ensure we are not left too soon during treatment with an oily cream that will create epidermal overheating. We will still have to keep replenishing a low-fat / high-water cream / lotion, to avoid epidermal overheating, but not as much.
RF treatment serums
Of course, using serums during low frequency RF treatment is unworkable as serums evaporate in no time.
Unless you provide a five-minute treatment, which is pointless, serums do not make any sense.
And contrary to popular belief, serums do not absorb deep in the skin either. They just stay on the epidermis and don’t penetrate (total waste of money - but try to explain that to “beauty experts”...)
Glycerol and propylene glycol products for low frequency RF treatment
There is also a fourth option as a contact medium for low frequency RF, comprising of glycerine, propylene glycol, hydroglycolic gels and hydroglycolic creams.
Glycerine* and propylene glycol** do not pose as much resistance to electricity as oil in these frequencies and they do not get absorbed as fast by the skin as water does, so they stand somewhere in-between, providing a good compromise.
Still glycerol and propylene glycol they heat up the skin perhaps more than we want to, so combining them with water, in the form of a hydroglycolic gel, or with water and oil, in the form of hydroglycolic gel-cream, is an even better compromise.
* Many low power RF machines are typically operated with pure glycerine as a contact medium, which heats up epidermis too much, creating skin redness and high temperature, and fooling the unsuspecting therapists and clients that the machine is very strong. It is not. It’s just that the glycerine overheats the epidermis, while deep inside, the dermis and hypodermis heat up very little.
** Propylene glycol is never used on its own, as it is too runny, making a mess everywhere. Propylene glycol also overheats the surface, just like glycerine.
RF treatment oils
Oil as a contact medium with a low frequency RF treatment would create electrical arcs between skin and machine, leading to burns. Definitely not recommended.
Radiofrequency treatment with no contact medium
Finally, having no contact medium with low frequency RF treatment would create electrical arcs between skin and machine, leading to burns. Definitely not recommended.
Radiofrequency at higher frequencies
The higher frequency machines (10MHz to 5GHz) are based on water molecule rotation creating heat in the deep tissues - and unfortunately on the skin surface too, depending on treatment medium.
RF treatment gels, creams and lotions
In this case, water-containing products (gels, creams, hydroalcoholic gels/creams, lotions serums) cannot be used as a treatment medium as they will be excessively heated, burning the epidermis.
So there are two options left: glycerine/propylene glycol or oil.
Glycerol / glycol products for high frequency radiofrequency
Again, in this case glycerine and propylene glycol will give the illusion of effective treatment as they will heat up on the surface of the skin making it look red, while deep in the skin (dermis/hypodermis) temperatures will remain lower.
This simply means ineffective treatment.
Water containing glycerine / propylene glycol products will heat the epidermis even faster, especially with high frequency RF, so they are not a good idea.
RF treatment oil
Oil on the other hand is completely inert at high frequencies, so it will allow the deeper tissues to be treated properly (if the machine is strong enough) without overheating of the epidermis.
RF treatment without contact medium
Non-movable (hands-free) high frequency radiofrequency applicators may be used without any contact medium, depending on the technology they use, always ensuring that sweat (water) does not accumulate.
However, RF designed to be used while gliding on the skin must always be used with a treatment medium, as described above.
Radiofrequency at intermediate frequencies
RF frequencies of 1-10MHz fall somewhere in-between. In that case some water or some oil can be the right or wrong ingredient in the contact medium formulation, depending on how the machine operates.
In most cases glycerine or propylene glycol is used, as it does not overheat like oil or water do at different frequencies.
Conductive gel for ultrasonic cavitation. What about oil, cream, lotion or serum?
With ultrasound things are not so critical as with radiofrequency, but the choice of conductive medium is still important.
Generally, high frequency ultrasound 1-10MHz would ideally require a gel, but creams or lotions can also be used.
At lower frequencies (30-300kHz) oil can also be used.
Again, serums evaporate very quickly so they do not make sense.
The electro-mesotherapy effect of RF / ultrasound
Both ultrasound and radiofrequency enhance the absorption of active ingredients, so if a quality, CONCENTRATED cream/gel/serum/oil is used, there is an extra benefit to be derived from the active ingredients in the contact medium.
The problem is that most such serums and creams are not that concentrated at all. Quite the opposite: most are in fact very diluted, especially all those “magic” serums advertised.
The other problem is that some actives may actually damage the ultrasound/radiofrequency applicator. Vitamin C (highly acidic) and essential oils are prime examples of that.
And there is yet another problem: some actives can cause irritation to the skin and using RF/ultrasound can make them even more irritating. A good example is strong exfoliating agents, such as glycolic acid. Combining RF and strong acids can be anything from tricky to dangerous - clearly not a good idea.
In summary
As we saw above, the choice of contact medium can turn a radiofrequency treatment more effective, more ineffective or even dangerous. This is because it can lead to low, medium or excessive heat on the surface (epidermis), depending on the combination of machine setup and contact medium.
Sometimes we need some heat on the epidermis (e.g. for acne treatment), while in other cases we don’t need any (e.g. for cellulite reduction, deep fat reduction).
So quite often it’s not just the machine and the operator technique, it’s also the contact medium that’s important.
Caution / Disclaimer
The analysis above is for educational purposes only, for the public to understand how contact media can affect the application of a radiofrequency / cavitation treatment.
This is NOT a professional instruction manual on the use of radiofrequency treatment contact media. Different machines, according to the technology they utilise, may require contact media IN CONTRAST to the analysis above - this is only a general article.
As a matter of safety, do NOT change your radiofrequency treatment contact medium without consulting with your machine manufacturer or distributor first. Blind experimenting can cause burns or other irritation. This article does NOT constitute professional instruction.
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