By Dipl.-Ing. Andreas Schachulski
Ultrasound is often mentioned in aesthetic medicine - but what does it really mean when you say "3 MHz"? In this article, I explain why this frequency in particular has a special physiological effect, how depth and heat effects interact and what cosmeticians should look out for to ensure that treatments with 3 MHz are safe, effective and long-lasting.
What does "3 MHz ultrasound" mean?
- MHz stands for megahertz, i.e. millions of oscillations per second.
- An ultrasound device with 3 MHz emits sound waves that propagate in tissue and are absorbed there - the higher the frequency, the more superficially this usually happens.
- The absorption of sound energy generates heat, mechanical effects (e.g. micro-vibration) and can trigger biological processes (e.g. blood circulation, metabolism) - without destroying the tissue.
Depth and warmth: How deep does 3 MHz really go?
A key aspect is the penetration depth - i.e. how deep the sound energy penetrates into the tissue and how much the temperature rises.
- Studies show that 3 MHz ultrasound can effectively heat superficial tissue (e.g. skin, upper dermis) at depths of around 0.8-1.6 cm [1].
- In experiments at 3 MHz, a temperature increase to 40 °C was even observed at a tissue depth of 2.5 cm [1].
- The higher the frequency, the stronger the superficial effect of ultrasound - at the same time the penetration depth decreases.
Biological effects of 3 MHz ultrasound
Why does 3 MHz not only have a physical effect (heat), but also a biological one?
- Increased circulation - heat causes blood vessels to dilate and increases the supply of oxygen and nutrients.
- Stimulation of collagen and elastin - mild heat and mechanical vibration stimulate cells to form new structural proteins [2].
- Fat cell activation (lipolysis) - Ultrasound stimulates fat cells to release stored triglycerides without destroying the cells [3].
- Inhibition of inflammation and regeneration - gentle ultrasound can have a positive influence on inflammatory processes [4].
Application in cosmetics: What is important?
| Factor | Meaning | What to pay particular attention to |
|---|---|---|
| Intensity and duration | Heat must be sufficient, but must not cause any damage. | Adjust parameters carefully, observe skin reactions. |
| Application medium (gel / oil) | Good conductivity is crucial. | Avoid air bubbles, use special ultrasonic gel. |
| Depth of the tissue | Different zones require different frequencies. | 3 MHz is ideal for skin and subcutaneous fat. |
| Repetitions / cure | Sustainability is achieved through series treatments. | Plan cures, document successes. |
| Security | Avoid overheating. | Follow the manufacturer's instructions and check the skin. |
Legal framework: The NiSV in the beauty salon
The NiSV - Non-Ionizing Radiation Protection Ordinance - has been in force in Germany since the end of 2020. It regulates the use of non-ionizing radiation in cosmetics, including ultrasound, radio frequency, laser and electrostimulation.
For beauticians, this means:
- Proof of specialist knowledge: Ultrasound treatments may only be carried out with recognized specialist knowledge.
- Documentation obligation: Each treatment and its parameters must be recorded.
- Customer safety: Skin anamnesis, information and consent are mandatory components.
More information from the Federal Office for Radiation Protection:
NiSV at the BfS
Differentiation from other ultrasound technologies
- 1 MHz vs. 3 MHz: 1 MHz has a deeper but slower effect; 3 MHz has a more superficial to medium-depth and faster effect [1].
- HIFU: focused ultrasound that destroys tissue in a targeted manner - in contrast to gentle 3 MHz applications that work in a regulatory manner [5]. Caution: High Focus Ultrasound (HIFU) may only be used by doctors
Conclusion
Ultrasound at 3 MHz is a gentle but effective method - scientifically sound and clearly regulated by law. For cosmeticians, it is a technique that delivers results without damaging tissue and can be used in accordance with the NiSV.
Author info
This article was written by Dipl.-Ing. Andreas Schachulski, Managing Director of Sana Medical Group GmbH. As an engineer with many years of experience in the development of medical technology systems, he combines technical expertise with practical application in aesthetic cosmetics. With Liposana3, he relies on a scientifically sound approach: gentle frequencies that activate cells instead of destroying them - for safe, effective and lasting aesthetic results.
Sources
[1] Hayes BT et al. Comparisons of heating using 1- and 3-MHz ultrasound. PMC522144
[2] Lee et al. Facial rejuvenation using ultrasound. SCIRP Journal
[3] Warner-Palacio et al. Noninvasive fat reduction using ultrasound therapy. MDPI
[4] Zhou et al. Therapeutic ultrasound and inflammation modulation. PMC7922048
[5] American Institute of Ultrasound in Medicine. Safety of cosmetic ultrasound. AIUM Statement