Why PureLift Uses 1.37 to 1.73 kHz for Facial EMS
Medically reviewed by
4 independent reviewers
Andrew Conrad Barile, Fisioterapeuta, Doctor en Terapia Física
Doctorado en Terapia Física (DPT), Fisioterapeuta Licenciado (PT)
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El Dr. Andrew Conrad Barile es Doctor en Terapia Física y CEO y Fundador de Xtreem Pulse LLC. Obtuvo su Doctorado en Terapia Física en Daemen College y aporta más de dos décadas de experiencia clínica y empresarial en terapia física pediátrica, terapia craneosacral e innovación en dispositivos médicos. Su profundo conocimiento de la anatomía humana, la fisiología muscular y la tecnología terapéutica ofrece un enfoque invaluable respaldado por la ciencia para la rejuvenecimiento facial y soluciones antienvejecimiento.
Bertica M. Rubio, M.D.
Director Médico, Clínica de Medicina Regenerativa y Antienvejecimiento | Médico Certificado por la Junta | Escuela de Medicina de Dartmouth
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La Dra. Bertica M. Rubio es una médica certificada y Directora Médica de la Clínica de Medicina Regenerativa y Antienvejecimiento en Redlands, California. Obtuvo su licenciatura en Ciencias en la Universidad Loyola Marymount y su título de Doctora en Medicina en la Escuela de Medicina de Dartmouth (Geisel School of Medicine). Completó su residencia en pediatría en el Centro Médico UC Irvine.
Con décadas de experiencia clínica, la Dra. Rubio se especializa en medicina para el manejo de la edad, medicina regenerativa, cicatrización de heridas y terapias con factores de crecimiento. Su práctica integra la ciencia médica basada en evidencia con tratamientos estéticos y regenerativos avanzados, ayudando a los pacientes a alcanzar una salud óptima y vitalidad juvenil.
La Dra. Rubio siente pasión por educar a los pacientes sobre la ciencia detrás del cuidado de la piel, el rejuvenecimiento facial y las tecnologías no invasivas como EMS (Estimulación Eléctrica Muscular) para el tonificado facial. Sus artículos para PureLift LAB combinan un conocimiento médico riguroso con orientación práctica para lograr resultados reales y duraderos.
Daniel Grinberg, MD, FACS
Otorrinolaringólogo y cirujano de cabeza y cuello certificado | Miembro, Colegio Americano de Cirujanos | Profesor clínico asistente, Escuela de Medicina Mount Sinai
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Daniel Grinberg, MD, FACS, es un otorrinolaringólogo certificado por la junta y cirujano de cabeza y cuello en ENT and Allergy Associates en West Nyack, NY. Obtuvo su título de médico en la Facultad de Médicos y Cirujanos de la Universidad de Columbia, completó su residencia en Otorrinolaringología en el Centro Médico de la Universidad de Nueva York y es profesor clínico asistente en la Escuela de Medicina Mount Sinai. Es miembro de la American College of Surgeons y de la American Academy of Otolaryngology.
La perspectiva quirúrgica de cabeza y cuello del Dr. Grinberg ofrece a los lectores de PureLift LAB una visión clínica más amplia, conectando la práctica de EMS en casa con la anatomía médica subyacente con el mismo rigor científico que aplicamos a cada especificación del dispositivo.
Prof. Dr. med. Ivo Buschmann
Cátedra de Angiología, Hochschule Médica de Brandeburgo | Director de Clínica, Clínica Universitaria de Angiología, Hospital Universitario de Brandeburgo | Ex Consultor Senior, Charité Universitätsmedizin Berlín
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El Prof. Dr. med. Ivo Buschmann es Catedrático de Angiología en la Medizinische Hochschule Brandenburg Theodor Fontane (MHB) y Director Clínico de la Clínica Universitaria de Angiología en el Hospital Universitario de Brandeburgo. Completó su formación médica en la Universidad de Hamburgo, fue becario de la Sociedad Max-Planck en el Instituto Max-Planck de Investigación Cardiaca y Pulmonar, y ocupó cargos de consultor senior en la Charité Universitätsmedizin Berlin Campus Virchow antes de ser nombrado Catedrático en la MHB en 2016.
El Prof. Buschmann es una de las principales autoridades europeas en arteriogénesis — el crecimiento y remodelación de los vasos sanguíneos impulsados por el flujo — con más de 150 publicaciones revisadas por pares y varias patentes en EE. UU. y la UE sobre dispositivos que estimulan el crecimiento de vasos colaterales mediante terapia controlada de tasa de cizalladura. Su investigación conecta la estimulación mecánica y eléctrica con la adaptación vascular, la microcirculación y la perfusión tisular.
Las contribuciones del Prof. Buschmann aportan a los lectores de PureLift LAB una perspectiva de biología vascular que complementa nuestra autoría clínica, de fisioterapia y de anatomía quirúrgica existente — explicando cómo la estimulación EMS activa no solo los músculos faciales sino también la microcirculación que los abastece, y por qué la administración inteligente es tan importante a nivel del flujo sanguíneo como en la contracción muscular.
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PureLift works between 1,370 and 1,730 Hz, which is the kilohertz range, and the choice of band is about comfort at the skin rather than power.
This article explains the reasoning, such as:
- Why skin resists low-frequency current more
- The three thresholds every person has
- What the band does not decide
- How this differs from microcurrent devices
and many more!
Frequency and intensity are two different dials, and confusing them is where most spec-sheet arguments go wrong.
Key Points:
Skin resists current less at kilohertz frequencies than at very low ones, so more of it passes with less surface discomfort.
Frequency governs how comfortably current crosses the skin; intensity governs whether a muscle contracts.
Everyone has three thresholds, sensory, motor and pain, and the gap between them varies by person and by area.
The band does not decide how deep the current goes or which tissue responds.
PDM moves the signal across 361 points inside that band so the pattern never repeats.
Why skin resists low frequencies more
Skin is not a simple conductor, and its opposition to current, its impedance, depends partly on the frequency of that current.
At very low frequencies the outer layer resists strongly, so a device has to work harder at the surface to get anything through, and the surface is where your sensory nerves are.
As frequency rises into the kilohertz range that resistance falls, so more current crosses for a given amount of surface sensation.
That is the whole reason for the band, comfort at the interface, and it is a smaller and more defensible claim than the ones usually attached to frequency figures.
The three thresholds
A review of kilohertz-frequency stimulation describes three thresholds present in everyone, the point you first feel the current, the point the muscle moves and the point it becomes painful (Ward 2009).
The useful setting is the second one, and the space between the second and the third is what a comfortable session lives in.
Working in the kilohertz range widens that space, which is why the same amount of muscle work can be delivered with less sting than a low-frequency device would produce.
The gap varies with skin thickness, hydration and area, which is why one setting can feel mild on the cheek and sharp along the jaw on the same face.
Frequency and intensity are different dials
Frequency describes how many times per second the signal cycles, and intensity describes how much current is delivered.
Whether a muscle contracts is a question of intensity crossing the motor threshold, and no frequency makes a sub-threshold current contract a muscle.
On a PureLift the band stays the same across the whole dial, and what changes as you move from level 1 to level 10 is the intensity, with nanocurrent at level 1, microcurrent at level 2 and EMS from level 3 upward.
Maximum intensity is 7 mA at 500 ohms on Face and Pro, 7.7 mA on Pro Edition and 9 mA on Pro Plus and GLOW, all inside the same frequency band.
What the band does not decide
It does not set a depth, and any claim that one frequency inside the band reaches the surface while another reaches muscle is describing something the physics does not support.
It does not select a tissue, since which tissue responds is a function of intensity relative to the motor threshold rather than of frequency.
It does not by itself make one device better than another, because two devices in the same band can sit on opposite sides of the motor threshold.
How this compares with microcurrent devices
Devices sold as microcurrent operate at much lower intensities, in millionths of an amp, and stay below the motor threshold across their whole range.
FOREO BEAR 2 publishes 680 microamps, Therabody TheraFace PRO 500, ZIIP Halo 309 and NuFACE Trinity+ between 170 and 200, with the last three taken from their FDA clearance documents since none prints the figure on its own site.
That is a difference of intensity rather than of frequency, and it is the difference that decides whether a device can contract a muscle at all.
Why the signal moves inside the band
Holding one frequency for ten minutes lets your nervous system learn the pattern, and once it can predict the signal the response falls away.
PDM, Pulsed Dynamic Modulation, moves the signal across 361 distinct points between 1,370 and 1,730 Hz so the pattern never repeats.
Pooling 22 studies, researchers found stimulation which keeps changing produced more evoked force with less fatigue than a fixed pattern (Cavalcante 2026), and a randomised crossover trial found varying frequency reduced how quickly people habituated (Avendano-Coy 2019).
One study disagrees (Papaiordanidou 2014), so PDM is designed to reduce accommodation and we never claim your muscles cannot adapt.
All of that work was done on limb muscle in laboratory conditions rather than on faces, so it supports the principle rather than testing this implementation.
Two related questions come up often alongside this one, and we have answered both in full: what frequency specific microcurrent means, and which muscles a session actually reaches.